Effects of Anxiety on Different Aspects of Information Processing

Running head: THESIS SUMMARY
Chapter 1
Name of the Student
Name of the University
Author Note

1THESIS SUMMARY
Research aims
The primary objective of this PhD research is to evaluate the existing association between
the speed of information processing and non-clinical anxiety levels, among older and younger
adults, in relation to a plethora of brain functions that encompass attention. These functions are
generally related to visual attention, selective attention, inhibitory cognitive control, reaction
time (RT) and intra-individual reaction time variability (IIVRT). Furthermore, another aim of
this research is to determine the relationship between the aforementioned non-clinical anxiety
levels and cognitive function (both subjective and objective), quality of sleep and demographics
such as, gender, age, education attainment, handedness and vision of the participants.
A multi-methodological approach was employed for meeting the primary objective,
which in turn would enhance the process of gaining a sound understanding of the non-clinical
anxiety that is commonly found among older and younger adults. This approach also helped in
evaluating the potential effects of anxiety on different aspects of information processing.
Furthermore, it also unraveled whether influence of interactions between sleep and anxiety affect
the functionality of information processing. The approach basically focused on the use of
questionnaires and tests based on pen and paper, in addition to some electronic psychophysics
tests. This helped in investigation of reaction time or speed of information processing.
Furthermore, the approach also evaluated a wide range of aspects that were encompassed by
inhibition and visual attention. The secondary objective was to investigate the importance of
other factors such as, lifestyle that might contribute to the brain function and anxiety.

2THESIS SUMMARY
Research objective
The primary objectives of this research are given below:
1) To look at the differences between older and young adults in terms of anxiety (especially
non-clinical anxiety)
2) Further understand how anxiety levels could also influence cognitive functions.
3) To deduce how anxiety could cause subjective memory complaint and how low levels of
anxiety could cause depression.
4) To gain a deeper understanding of the correlation between anxiety (subclinical anxiety in
particular) and the higher brain faculties, such as, visual attention related information
processing, speed of information processing, and the objective measures that encompass
different cognitive functions. In addition, the objective is also to understand the
demographics of the sample population (younger and older adults) and their relation to
subjective memory complaint.
5) To investigate the association between speed of information processing and non-clinical
anxiety
6) To determine the relationship between levels of non-clinical anxiety with speed of
information processing and inhibition of cognitive control, in addition to attention
associated functioning
7) To evaluate the influence of non-clinical anxiety on IIVRT, RT and attention
8) To determine the association between sleep quality and subclinical anxiety, in regards to
information processing speed and cognitive performance
9) To evaluate the interactions between anxiety and the aforementioned factors

3THESIS SUMMARY
10) To make recommendations for evaluation, treatment and reduction of non-clinical
anxiety among older patients
Research question
 Does subclinical anxiety creates an impact on the brain functions, vision, cognitive
functions, memory, and lifestyle of older people, compared to their younger
counterparts?
 Is there any association between speed of information processing and non-clinical
anxiety, during the ageing process? Is there any difference between older and younger
adults? Does the cognitive performance vary among males and females?
 Is non-clinical anxiety capable of influencing attention-related functioning and
inhibitory cognitive control among older and younger adults?
 Does poor RT and IIVRT characterise ageing in older adults, compared to their
younger counterparts? Is it influenced by non-clinical anxiety?
 Is subclinical anxiety found to affect the sleep quality? Does that relation influence
information processing speed and attention?

4THESIS SUMMARY
Introduction
Speed of information processing is generally considered as an essential aspect of
dementia and ageing that facilitates the process of clinically diagnosing dementia. This
processing speed can therefore be defined as the cognitive ability that helps to understand
responds to particular information that is received, which might include movement, auditory and
visual. The clinical importance of information processing speed has also been illustrated by the
recently revised DSM-5 criteria that elaborate on the fact that processing speed is always
measured in regards of attention-related function that facilitates the process of diagnosing
dementia and its associated conditions (Torrens-Burton et al., 2017). Measurement of processing
speed during the diagnostic procedure is in fact related to the well-defined relationship between
the functional/structural integrity of gray and white matter with the behavioural measures of
speed. The structural integrity has been found to be detrimentally affected among AD patients,
when compared to reduced cognition during normal ageing (Phillips et al., 2013).
However, DSM-V criteria is often vague and fails to define specific information
processing speed test, in addition to MCI or dementia, that might create an influence on the
processing speed. This would bring about significant changes in clinical test results and their
interpretation. Non-clinical anxiety levels have been identified as a potential factor that
influences information processing speed. However, there is lack of supporting evidences for the
same. Several studies have been conducted that took clinical anxiety into account and
investigated its association with the speed of information processing. This provided evidence for
the association between high levels of anxiety and their subsequent impacts on brain functions
(Tobias, 2013). However, a flaw in the research studies were that low anxiety levels in older and

5THESIS SUMMARY
younger adults fail to influence brain functions that encompass processing speed, anxiety,
cognitive inhibition and vision. Although previous findings have examined the impact of
objective cognition on the essential brain functions and ageing, there is lack of adequate
evidence that took subjective memory into consideration, for the same (Brown et al., 2014).
Previous research have also proposed the role of methodological factors, such as, the kind of
tests on attention and processing speed in MCI, dementia and ageing. This forms the basis of
measuring processing speed, with the use of attention-related tests (Tales & Basoudan, 2016).
Information processing speed is an essential brain function since it refers to the cognitive
ability or the time that is required for accomplishing a mental task. In other words, it is an
essential brain function because it encompasses the duration between receiving and showing
response to a stimulus. Its importance as a brain function can also be attributed to the fact that
poor processing speed means signifies difficulty in conducting certain determined tasks such as,
problem solving, reading, taking notes, listening and or engaging in conversations. Poor speed
might also interfere with higher executive functions, and makes it difficult for such an individual
to set goals, plan, make decisions, pay attention, or begin tasks (Anderson & Hinton, 2014). It is
of relevance in dementia because research studies have established the fact that abnormal
electrical fields of event-related potentials might lead to poor information processing in dementia
patients, thereby worsening their cognitive impairment (Kriegeskorte, 2015). Attention is also an
important brain function that is needed to human behaviour. It refers to the selection process for
internal or external events that have to be maintained at specific awareness levels. Its importance
as a brain function can be related with the fact that attention helps the brain to selectively
concentrate on certain aspects of the surrounding environment, while ignoring a range of other
things (Bari & Robbins, 2013). Furthermore, the fact that in addition to progressive impairment

6THESIS SUMMARY
of memory, dementia patients often report problems in selective or focused attention, dementia
diagnosis involve attention and processing speed measurement. Thus, the research found it
necessary to consider these two aspects, in relation to ageing (Wesnes et al., 2015).
Showing consistency with the previously mentioned thesis summary, the primary
objective of this research work would be to evaluate the effects of non-clinical anxiety levels on
information processing speed and its variability, as well as attention, among older and younger
adults. The possible relationship between anxiety and subjective memory functions will also be
investigated, in regards to brain functions related to RT, IIVRT attention and inhibition. Thus,
this will be a novel research since it will take into consideration the subjective memory
functions. The study will also consider quality of sleep, in relation to non-clinical anxiety,
demographics and the aforementioned factors.
What is anxiety?
Anxiety refers to emotional manifestation that is characterized by unpleasant states of
inner turmoil that are often accompanied by display of abnormally nervous behavior. Such
behaviour commonly includes somatic complaints, pacing back and forth, and rumination. Such
anxiety symptoms might often be experienced by young and older adults that might make them
face nihilistic feelings or existential crisis. Until recently, anxiety disorders were considered to
decline with the ageing process (Lader, 2015). However, anxiety disorders have frequently been
found associated with older adults, upon encountering traumatic events related to acute illness or
falls. The immediate effects of anxiety include manifestation of unpleasant feelings over
anticipated events such as imminent death. These can result in bypassing the overall actions,
regardless of the individuals desire (Meichenbaum & Turk, 2017).

7THESIS SUMMARY
It results in an expectation of future threats and leads to feelings of worry or uneasiness
that are more commonly unfocused and generalized, as a direct response to situations that are
perceived as menacing. Its immediate effects on brain include high activity as a response to
emotional stimuli, received by the amygdala. It also results in overpotentiation of the limbic
system (nucleus accumbens and amygdala) (Qin et al., 2014). Thus, anxiety plays an important
role in understating about dementia and the ageing process. There is lack of evidence for low
anxiety levels and their possible influence on essential brain function. Thus, it is essential to
measure the levels of anxiety for gaining a deeper understanding of the aforementioned brain
functions. This will be measured by using State-Trait Anxiety Inventory (STAI) and Beck
Anxiety Inventory (BAI) tests (Livingston et al., 2013).
It is imperative to gain a sound understanding of the different types of anxiety namely,
existential, trait, test and performance, social, stranger and intergroup anxieties, for the purpose
of the research (Kesebir, 2014). According to Fazeliet al., (2014), anxiety experienced for a short
time span is explained by the term state anxiety that encompasses unpleasant emotions for
existing in complicated or threatening situations. This anxiety is not associated with the
cognition, health or social status of the affected person. It gets eliminated with removal of the
disturbing stimulus (Bryant et al., 2008; Eysenck & Derakshan, 2011; Paulus & Stein, 2006).
Trait anxiety refers to the tendency that leads to long term emotional arousal. It lasts longer,
when compared to state anxiety. Both of the above mentioned anxiety types signify unpleasant
feelings of stress, upon confrontation with unpleasant situations. Burgess et al. (2014) argued
that state anxiety is ephemeral. This is associated with specific situations that trigger stress
among patients. Furthermore, Harrington et al. (2017) opposed the view and provided evidences
for long term effects of trait anxiety. Mirza et al. (2017) also opined that state anxiety gets

8THESIS SUMMARY
resolved after a certain time period, while prolonged duration gets exhibited by trait anxiety.
Hence, there exists an association between these anxiety types. State anxiety is also dependent on
the interaction between trait anxiety and situational stress (Derakshan & Eysenck, 2009).
Unresolved state anxiety contributes to trait anxiety. In concision there are different types of
anxiety. However as a P.hD research specific types of anxiety will be covered to meet the
research objectives that can influence the life of the individual. To understand the key concepts
of the paper, the state and trait anxiety seems to provide a strong background.
Recently researchers have found that several older adults are being forced to live in
solitary confinement that results in their social withdrawal and eliminates all forms of human
contact (Arbus et al., 2014). This leads to a traumatic situation that adds to their anxiety and
worsens the overall functioning of the brain, which in turn creates an impact on the behaviour
(Meichenbaum & Turk, 2017). This is generally manifested in the form of trait anxiety, across
their lifespan where the older people face threatening situations related to their isolated existence
(Fazeli et al., 2014). Trait anxiety is further enhanced by the fact that the older people fail to
express their feelings appropriately due to changes in the cognitive faculties of the brain, in
addition to a reduction in processing speed. Hence, state anxiety often leads to trait anxiety in the
elderly. This calls for the need to control them at non-clinical levels to mitigate the direct
impacts on brain and behaviour.
Older adult patients, living in hospitals have a prevalence of 43% for anxiety disorders.
Following collection of samples from the older adults, suffering from Alzheimer’s (15-25%), 15
to 56% of them had manifested anxiety symptoms (“Mentalhealth.org.uk,” 2017). Statistical
reports suggest that 15.3% older adults suffer from anxiety disorders. Furthermore, prevalence of

9THESIS SUMMARY
anxiety is higher among patients suffering from depression (“Mentalhealth.org.uk,” 2017).
Moreover, the population percentage suffering from anxiety has shown dramatic increase since
the year 1974. Approximately 47% of older adults have been found to suffer from different
anxiety types, across the UK (“Ageuk.org.uk,” 2017). In addition, anxiety, in combination with
depression is found among 89% individuals, aged 75 years or more. 28% of females and 22% of
men also suffer from anxiety, in the nation (“Mentalhealth.org.uk,” 2017). Thus, it can be
suggested that anxiety disorders are extremely common, which in turn results in negative health
impacts on older people residing in the United Kingdom. This calls for the need to adopt
sustainable solutions for addressing the high prevalence of anxiety and its subsequent impacts on
brain function and behaviour.
Further estimates suggest that approximately 85% of older people fail to receive proper
medication or community help that can help them cope with their anxiety. Approximately 44
million people have anxiety globally, which in turn might be triggered by lack of pacification of
the risk factors and poor healthcare support (“Ageuk.org.uk,” 2017). The symptoms go unnoticed
most of the time, thereby contributing to the failure of delivering appropriate care services to the
patients that aggravates their situation (Fazeli et al., 2014). However, some patients do not
identify their anxiety conditions that are unnoticed by healthcare providers. This prevents the
former from receiving any treatment (“Mentalhealth.org.uk,” 2017). Thus, there is a need to
unravel the association between ageing and anxiety, to understand the effects created on the
cognitive function.
Subclinical anxiety have also been recognised to occur on a wider scale, when compared
to other anxiety disorders, an have a prevalence rate of 15-52% (Bryant et al., 2008; Sherbourne,

10THESIS SUMMARY
Sullivan et al., 2010; Yochimet.al., 2012). However, subclinical anxieties are generally not taken
into account, during the diagnosis of dementia or in research studies that evaluate effects of
dementia on subjective memory function, or functional integrity of attention and processing
speed in the ageing population. Most of the research studies focused on clinical anxiety,
pathophysiology and its symptoms. Studies that investigated the correlation between anxiety and
brain function, always considered high anxiety levels. Owing to the fact that subclinical anxiety
has not been taken into consideration in clinical research, and the previous researchers have
given due focus on attention and information processing speed, this novel research aims to shed
light on non-clinical and sub-clinical anxieties and their effect on vital brain functions.
Risk factors for anxiety
Three classes of risk factors that might make an individual more susceptible to
development of anxiety symptoms are restitution factors (Lindesay et al., 2012), pre-morbid
vulnerability factors, and destabilisation factors (trigger onset of particular episodes). Exposure
to these risk factors are found to differ across the lifespan of an individual (Acierno et al., 2006).
Major risk factors are also classified on the basis psychological, biological or social. The primary
biological factors that increase risks of anxiety symptoms include functional limitation, poor
self-perceived health and chronic health problems (Lindesay et al., 2012; Vink, Aartsen &
Schovers, 2008). Psychological risk factors encompass poor coping strategies, neuroticism,
psychopathology and external locus of control (Vink et al., 2008).
Some social risk factors that have been identified to cause development of anxiety
disorders, at a later stage in life involve demographic factors such as, gender and poor
educational status (Vinket al., 2008), in addition to the quality and size of social networks

11THESIS SUMMARY
(Lindesay et al., 2012). Low income, lack of social contacts, adverse life events, and
childlessness has also been significantly associated with high anxiety levels. Negligible evidence
exists on the discrepancies in anxiety prevalence rates among different ethnicities and races
(Lindesay et al., 2012). This area needs in-depth investigation and can be considered as a major
research gap.
Medical practitioners offer optimal quality healthcare services to individuals, who have
been subjected to anxiety symptoms due to a range of genetic and environmental factors. Lack of
awareness of the situation and presenting complaints usually result in a delay in taking help from
healthcare professionals. Symptoms of anxiety that go unnoticed often create huge disruption in
their daily life and prevent them from seeking help from advanced medical practitioners.
Dementia also acts as a major risk factor that aggravates the clinical condition and leads to the
onset of anxiety symptoms among the older adults. An individual suffering from dementia is
found to biologically experience profound grief or loss of ability that pertains to negotiation of
new stimulus and information. Dementia diagnosis might encompass moving to nursing home or
new residence, and changes in the arrangements of caregivers (de Bruijn et al., 2014). Dementia
diagnosis also involves several changes in the environment such as, hospitalisation, travel or
presence of houseguests. Fatigue, fear and misperceived threats might result in a confused state
of mind among the older adults, which in turn increases their anxiety. Initially, little attention
was given to anxiety symptoms, in relation to dementia (Beerens et al., 2013). However, recent
investigations have suggested that there is a high prevalence of anxiety in the older population,
where dementia is found to be a common neurological disorder (Joling et al., 2015). This results
in poor health outcomes and directly affects the quality of life and wellbeing. Anxiety, fear and
stress are most often considered as a normal and occasional part of life. However, such stressful

12THESIS SUMMARY
conditions result in an atrophy of the hippocampal areas of the brain that is involved in spatial
navigation and long-term memory. Rates of anxiety have been found to be significantly high in
patients suffering from vascular dementia (Wachinger et al., 2016). While some studies provided
evidence for the fact that anxiety is one of the symptoms manifested by a dementia patient, other
studies suggested that high anxiety levels could directly create an influence on the life of the
older adults, thereby increasing risks of dementia or other kinds of cognitive impairments
(Orgeta et al., 2015). Thus, depression, stress and anxiety are common conditions, experienced
by patients diagnosed with dementia. It can be deduced from research findings that positive or
negative thoughts that contribute to anxiety are commonly faced by all individuals, regardless of
their age, and usually vary in their severity (Desrosiers et al., 2013). However, failure to
diagnose such anxiety disorders during the early stages of life might exacerbate the condition and
lead to worsening of the mental status.
Biological basis of brain function for information processing speed
One of the major challenges encountered in cognitive neuroscience encompasses the
process of gaining a sound understanding of the correlation between structural and cognitive
changes on an ageing brain (Raz, 2004; Raz & Rodrigue, 2006). Furthermore, it also becomes
difficult to differentiate between these changes, in relation to pathological and normal ageing
process (Johnson, Storandt, Morris, & Galvin, 2009). The process of ageing is found to exert
impacts on several molecules, cells, and cognition. During ageing, there is shrinkage in the
volume of the brain, particularly in the frontal cortex. Ageing creates an effect on the body
vasculature that results in an increase in blood pressure and onset of other health complications,
such as, an increase in the likelihood of ischemia or stroke. Although changes brought about by
dementia and stress are quite significant, changes in the entire structure of human brain occurs

13THESIS SUMMARY
from the time of conception. Hence, there is a need to gain a sound understanding of the
structure and function of the brain, in addition to the pathological, normative, and cognitive
process of brain development. As this is the P.hD research not all the changes in the brain due to
ageing will be covered. The main focus would be on the IIV and RT, information processing
speed, and attention.
White matter is found in the deeper, subcortical neuronal tissues of the brain. It is
composed of nerve fibers that are surrounded by myelin sheath or covering that gives the white
colour. It also leads to the establishment of connections between regions of grey matter. Changes
in white matter have been found to contribute to a range of conditions namely, inflammation,
multiple sclerosis, damage of oligodendrocytes, and accumulation of amyloid plaques that lead
to Alzheimer’s disease. Such changes in the white matter occur at a rapid rate in older adults.
Due consideration must be given to the fact that dormant oligodendrocytes have the capability of
getting activated, while a person suffers from demyelinating disease. The entire mechanism of
activation of white matter involves its repeated activation. Some changes also occur in the white
matter in cases where memory formed networks or connections between the lateral frontal or
parietal areas of the brain (Voelker, et al., 2017).
This often contributes to a range of symptoms such as, numbness or weakness. Changes
in the grey matter also trigger the onset of various diseases such as, loss of short-term memory in
people suffering from dementia. This often makes it difficult for the individual to remember
minute details. In addition, the individual also forgets about certain basic things, and misplaces
items, such as, keys of house or vehicle. Shrinkage in tvolume of white matter, with the normal
process of ageing is generally found to be larger than that of grey matter (Harada et al., 2013;
Rogalski, Stebbins & Barnes et al., 2012). Research studies have also found reduction 16-20%

14THESIS SUMMARY
reduction in volume of white matter, among individuals, aged above 70 years, upon comparison
to their younger counterparts (Harada et al., 2013). This decline has generally been found in
areas of the precentral gyrus, corpus callosum, and gyrus rectus. The aforementioned areas are
found to constitute fewer than 6% of the grey matter areas that show a decline (Harada et al.,
2013). Integrity of white matter also reduces with an increase in age (O’Sullivan, Summers &
Jones et al., 2001). Reaction time refers to the amount of time that occurs between receiving a
stimulus and responding to it. Reaction time has been identified as an index of connectivity of
white matter (Kinnunen et al., 2010). On the other hand, intra-individual variability refers to the
within person change in behaviour manifestation of a person. It acts as an essential component of
cognitive decline that is related with anxiety and dementia, during ageing (Mazerolle et al.,
2013). Such decline with an increase in age, is most prominent in the anterior regions of the
white matter, and commonly associated with executive function, and reaction time deficits
(Harada et al., 2013).
Subjective and objective cognitive function
Subjective cognitive function (SCF) is the decline in the cognitive function perceived
when there is no deficit, observed in the objective measures (Hill et al., 2016). Mild cognitive
impairment is diagnosed by the key factor called Objective cognitive function (OCF). It may
occur with the serious changes that results in decline in the objective measures of the cognitive
function. Amongst the various causes of loss in cognitive function like dementia, Parkinson’s
disease and Alzheimer’s, the most commonly prevalent is the Alzheimer’s disease.
SCF is characterised by the forgetfulness and poor memory. Subjective decline of
memory in many people is observed to begin middle ages that is in their 40’s. However, there are

15THESIS SUMMARY
no psychometric tests identified to measure the subjective decline in the cognition related to
Subclinical anxiety at the time of aging (Takeda et al. 2008).
Measurable cognitive decline are referred to objective cognitive function. It is caused by
any chronic illness like diabetes or Alzheimer’s, or may occur as consequence of ageing, or due
to psychological impairment such as depression and anxiety. OCF has been characterised by the
hearing loss, and decline in sensory processing (Lin et al., 2011). There is little resolution in
regards to the how the subjective cognitive complaints explain then impairment in the OCF The
assessments of the SCF and OCF are no formally validated or are brief. OCF is usually measured
using instruments like MMSE (Mini Mental State Examination) or MoCA.
According to the Diagnostic and Statistical Manual of Mental Disorders fifth edition or
DSM-V criteria, the Mild Cognitive Impairment (MCI) is diagnosed formally by considering
OCF as key criterion (American Psychiatric Association, 2013). Other criteria used for diagnosis
of MCI are the absence of dementia, independent in functional abilities and informant or self
reported cognitive complaints (APA, 2013). A metaanalysis by Reijnders, van Heugten and van
Boxtel (2013) indicated the treatments for improving the MCI condition. As per the results the
patients undergoing cognitive training can show improvement in the memory performance, OCF,
information processing speed, and executive functioning. However, cognitive training does not
show any improvement in the activities of daily living (Reijnders et al., 2013). In other study by
Bondi et al. (2014) people diagnosed with MCI were categorised as three subtypes. Two methods
that focused on diagnosis of mild cognitive impairment were compared in the study. Comparing
the cluster groups, and examining them for APOE allele frequencies suggested that both the
criteria resulted in the manifestation of mild impairment in the amnestic subtype and severe
impairment in the mixed or dysexecutive subtype. MCI participants who were diagnosed with

16THESIS SUMMARY
the use of neuropsychological criteria were found to yield significant CSF AD biomarker
associations, dissociable cognitive phenotypes, and more stable diagnoses. Moreover, they also
identified higher percentage of participants progressing to dementia, upon comparison to the
conventional diagnostic criteria for MCI. However, the actuarial neuropsychological method
failed to produce any subtype that was performed within the normal limits on cognitive testing,
showing dissimilarity with the general or conventional diagnostic method. Hence, the results
identified the need of bringing bout refinements in the diagnosis of MCI for incorporating
comprehensive neuropsychological methods (Bondi et al. 2014).
The affect on information processing speed was not studied due to lack of comprehensive
neuropsychological method. It is constituted as a research gap. It also may be because there are
multiple variations of SCF and OCF depending on the impairment of the specific cognitive
functions. It may be related with electroencephalograph-based reaction time tests which are
associated with different brain functions. There may be possibility that as a part of diagnosis it is
rarely assessed. Hence there is a refinement required in the MCI diagnosis for better
understanding of this parameter. This makes the present study novel one. It will be discussed in
detail in subsequent chapters.
Attention
A response to the particular stimuli is referred as Attention. Using the immediate memory
span a slight decline in the attention has been observed in the late life. Harada et al. (2013); and
Salthouse (2009) measured through repeating the string of digits. A noticeable age affect has
been observed with Selective and divided attention, which are considered to be the tasks of
complex nature (Harada et al., 2013; Salthouse, 2012; West & Alain, 2000). In selective

17THESIS SUMMARY
attention a person focuses only on one out of many stimuli while filtering the distractions. On the
other hand the divided attention allows an individual to focus on the multiple activities such as
cooking meal while talking over phone (Harada et al., 2013).
When youngsters and the adults are subjected to the tests like holding memory while
simultaneously manipulating the information or other tasks like working memory, the
performance of the older adults was worse (Singh-Manoux, Kivimaki & Glymour et al., 2009;
West & Alain, 2000). It may be due to difficulty of older adults in calculating the simple tip on
the bill or perceive the strings of letter in right alphanumerical sequence (Harada et al., 2013;
Singh-Manoux et al., 2009). According to Havranek et al. (2016) several anxiety episodes have
also been found associated with poor attention among individuals.
Lowered attention decreases the ability of a person to execute important tasks, which in
turn lowers their potential and makes them less productive. This subsequently results in a loss of
memory that leads to their failure in retaining new information. Non clinical anxiety often makes
it difficult for older adults to pay more attention, while hearing a speech, when compared to the
younger adults (Jones et al., 2016). Lowered attention can be attributed to insignificant worries
or attention to irrelevant information. According to Cunningham et al. (2016), the aged people
have reduced self dependency for performing daily activities which may cause to affect the
attention severely. Anxiety also affects the attention. Consequently, the anxious people fail in
specific activities. In the subsequent chapter, visual attention, attention, and RT in relation to low
anxiety level will be discussed.

18THESIS SUMMARY
Reaction time and intra-individual reaction time variability
Intra-individual variability (IIV) refers to the variation in cognitive person within a
person overtime. It is measured by reaction time (RT) trial by trial when performing the given
cognitive task (Haynes et al., 2017). There is a great body of literature on decline of cognitive
function during ageing as well as slowing of the information processing speed. There is more
data emerging on the variability in older adults considering the response speed when compared
to the younger adults. It has also been proposed that IIV is the sign of the neurobiological
disturbance as also evident from the greater variability in individuals with dementia, Parkinson’s
disease and mild cognitive impairment. Based on various studies using the magnetic resonance
imaging technique, variability and structural brain measures were found to be linked. There is a
link between IIV and white matter hyperintensities (WMH) in healthy ageing people as well as
with white matter volume, diffusion tensor imaging metrics. It was considered to be attributed to
the poorer neuroanatomical integrity, and frontal lobe damage. However, in the healthy people
there was a link established between the IIV and prefrontal and frontal WMH. Further, in
individual with the mild cognitive disorder, when compared to those with the normal cognition a
stronger association was found between IIV and structural MRI measures. On the other hand the
longitudinal studies showed that there was an increasing IIV following the cognitive decline.
Some other studies established the possibility of white matter hyperinensities with greater risk of
developing Alzheimer's disease in future. The relationship between the white matter intertie and
variability as been well established based on the people on verge of and yet undiagnosed
dementia (Haynes et al., 2017).
To develop further insights the link between information processing speed and its
variability, the study by Haynes et al. (2017) investigated the relationship between IIV and

19THESIS SUMMARY
WMH in older individuals. As per results in the IIV-WMH relations frontally-supported
cognitive processes were found to be related. In the white matter structures, RT measures, the RT
measures were sensitive compromise in older people without dementia. In similar study by
Jackson et al. (2012) increased RT and IIV was observed in ageing people with Alzheimer
disease. As per the results there was a association found between the less IV and larger volumes.
In the tail of RT distribution there was less slowing. Faster modal reaction time was observed in
the inferior parietal white matter volumes. These results support the white matter integrity as its
role in IIV. As per these results there is chance of IV breakdown both in normal ad pathological
ageing.
However, previous studies does not address the impact on the other parameters such as
SCF, OCF, sleep quality or any relation of IIV and WMH with anxiety and depression.
Therefore understanding the association of IIV and RT with these parameters in older adults with
dementia as a present aim of the study is justified.
Cognitive inhibition
Cognitive inhibition is the ability of the mind to filter out stimuli that is irrelevant to the
mind’s current state or the present activity at hand. This process is either international or
unintentional (Peter, Hertwig & Hoffrage, 2004). This ability may be due to neural inhibition
where neurons can stop the elements of thoughts or regulate. When the excited neurons reduce
the activity of the neighbors to disable the spread of action potential in lateral direction, it is
called as lateral inhibition (Davidson, Dima & Loren et al., 2006).
Therefore, another aim of the study is to determine if cognitive inhibition is correlated
with the non-clinical anxiety levels, as well as determine the relationship between the cognitive

20THESIS SUMMARY
inhibition and RT, IIVRT and the other related factors. The detailed discussion would be
continued in subsequent chapters.
Sleep Quality
Age affects the sleep quality and sleep pattern. It further affects the cognitive
performance as well as information processing speed. Ageing leads to sleep deprivation that
affects the quality of sleep. Thus, older people do not sleep comfortably making their skin age
faster (Minaker, 2011). Anxiety decreases the body’s ability to calm down, which gain hampers
the sleep quality. Further, discussion in subsequent chapters would involve affect of subclinical
anxiety on sleep quality, attention and information processing speed.
Years of education
It is unclear from literature if years of education are associated with the pattern of
anxiety. Bjelland et al. (2008) examined the cross sectional link between educational level and
anxiety symptom level stratified by age. As per results there are greater association between the
low education level and high anxiety levels and depression. There was decease in coefficient
with increasing age. However, there was an exception for the age group 65-74 years. However,
there was an accumulation of protective effect of education over time. There is but an
inconclusive data if a higher educational attainment protects against anxiety in older adults. As
per McLaren et al. (2015) people with higher education perform well in a given cognitive task
despite depression symptoms. On the other hand people with low education performed worse due
to high depression symptoms. These results were obtained from healthy people without
dementia. These results were however not found to have any effect on information processing
speed. There is but inconclusive data about education protecting during elevated depression

21THESIS SUMMARY
symptoms against the verbal memory deficits, when controlling for age and sex. There is no
clear data available on the affect of education on people with dementia and their information
processing speed and attention. Further, discussion in subsequent chapters will be done on
affects of sub-clinical anxiety and education on information processing speed, attention and other
parameters.
Sex
Information processing speed in previous studies was showed to be to be faster in males
in comparison to females. The results were consistent in both younger adults (Karia et al, 2012)
and other age groups (Dykiert et al, 2012, Fozard et al, 1994). Further, evidence has been
gathered from previous research on the significant increase in IIV in females in comparison to
male counterparts (Philips et al, 2013). Based on these findings if the affect of sex on slowing
of the information processing speed is not taken into consideration as a factor, it may influence
the characterization of the way information is processed in women and men. There is a bulk of
study conducted on dementia and MCI. However, there is a staunch that there is a
misinterpretation related to what is constituted as the normal speed of information processing in
the healthy control. Therefore, it is necessary to carry a visual search paradigm where more
participants will be used than the previous research, considering the sex as potential factor to
influence attention, information processing speed and IIV.
Handedness
There has always been a controversial data on the affect of handedness on cognitive
functioning and age related decline such as SCF, OCF, and information processing speed. Left
handedness is considered to be associated with more age related decline (Van der Elst et al.,

22THESIS SUMMARY
2008). There is no particular evidence on the negative or positive effect of the handedness on sub
clinical anxiety. The aim of the research to deduce such relationship is justified and will be
discussed in subsequent chapters.
Vision
Visual information is processed through brain involving complex system of neurological
activity. Ability to visualize affects the healthy visual processing and poor ability influences
concentration and areas of processing speed and accuracy (Owsley, 2013). As a P.hD research
the aim is to identify the influence on the information processing speed using the computer based
task. It will better help understand if the vision problems could affect the results.
Measurement of cognitive functions and Anxiety
The aim of this research is to determine the relationship between non-clinical anxiety
levels and the aforementioned cognitive function. Neuropsychological assessment constitutes an
integral part of the health care practice. It is useful for diagnosis, planning, and treatment
evaluation. In older adults it is valuable for diagnosis of neuro-degenerative disorders and its
treatment (McKhann, Knopman & Chertkow, 2011; Lezak, Howieson & Loring, 2004;). Various
psychological factors influence the cognitive performance. It is important for accurately
interpreting the tests results. Anxiety is one of these factors.
Based on the literature it can be deduced that anxiety symptoms influence the cognitive
functioning, especially those common than the depressive symptoms (Bryant, Jackson, & Ames,
2009; Grenier et al., 2011; Gum, King-Kallimanis, & Kohn, 2009). These symptoms affect the
activities of daily living such as work and education, the brain and cognitive functions as well.

23THESIS SUMMARY
Owing to the fact that previous research studies failed to consider this aspect of anxiety effects,
we will evaluate or look at the effect of non-clinical anxiety symptoms in older adults impair
information processing speed, attention, semantic and episodic memory.
To fulfill the aim of the research, a methodological approach was used. It includes pen
and paper tests and questionnaires. We used Beck Anxiety Inventory (BAI) to exclude anyone
who got high levels of depression, because this research was focused on evaluating anxiety only.
I also attempted to look at the impacts of low levels of anxiety on risks of depression. To
measure the sleep quality the instrument used is PSQI (Pittsburg Sleep Quality Index).
Instruments used for Subjective memory function and OCF test PRMQ (Prospective and
Retrospective Memory Questionnaire) and MoCA (Montreal cognitive assessment) are used
respectively. Further, computer-based psychophysics-based tests such as, Simon task, Go/NoGO,
task, and Stroop task are used to measure the cognitive inhibition in relation to information
prossing speed and its variability. Also Simple and Choice reaction time are used to measure the
RT and IIVRT, as well as visual search task to evaluate the visual attention, information
processing speed and its variability.
General Implications Concerning Research related to Anxiety
A various factors are to be considered when conducting research on ageing and anxiety,
dementia as well as subjective and objective cognitive impairment. Firstly, Studies pertaining to
cognitive function especially those related to memory, information processing speed and
executive function have mostly involved participants who have fulfilled the full diagnostic
criteria for depressive disorders or comorbid anxiety or other anxiety disorders (Seignourel et al.,
2008; Yochim et al., 2013). Considering the high prevalence of subsyndromal anxiety this

24THESIS SUMMARY
approach is at odds (Potvin et al., 2011; Yochim et al., 2013). In ageing and detention cases,
appropriate and accurate assessment of the anxiety related affects in anxiety disorders and sub-
clinical levels of anxiety is needed. It will facilitate appropriate case characterization ad
treatment. Anxiety is treatable and requires pertinent strategy for intervention that can dissociate
the effects of anxiety from the effects of other neuro-degenerative disorders. Anxiety and
neurodegenerative disorders can be treated by reducing the symptoms.
Secondly, Anxiety related research has mainly focused on the young adults for exploring
the theoretical approaches. There is lack of sufficient evidence on relationship between the
subclinical anxiety and cognitive function in younger adults. The aim of this research is to
determine the relationship between the aforementioned non-clinical anxiety levels and cognitive
function (both subjective and objective), quality of sleep, and information processing speed.
There is a paucity of evidence pertaining to affect of anxiety on subjective cognitive changes and
memory in both older adults with dementia and mild cognitive impairment as well. Thus, it is
imperative to conduct research on this age group to understand the effects of anxiety and
subjective memory changes.
Thirdly, previous research fail to address the instruments needed to define and diagnose
the events associated with cognitive function in both clinical and research domains. There is no
specific criteria highlighted in previous research in this area that will help identify the non-
clinical anxiety except for scales, used for measurement. The need of assessment tool has not
been addressed that can help distinguish the symptoms specific for anxiety rather than masked
with common symptoms of dementia and anxiety (Wetherell et al., 2004; Gallagher et al., 2008;
Yochim et al., 2008; Qazi et al., 2003; Kroenke et al., 2007). The primary research gap identified
from these studies can be attributed to the fact that an overlap of dementia and anxiety symptoms

25THESIS SUMMARY
failed to mark the symptoms or behavior that are exclusive to anxiety disorders. There is also
need of procedure to detect the specific anxiety related criteria, based on which the patients and
control group of research participants can be distinguished when involved in ageing and
dementia-related research studies. Moreover, low levels of anxiety has also been found to exert
an effect on the vital functions of the brain by creating a disruption in the balance of activity,
present in emotional centers of the brain, in comparison to the cognitive centers. Researchers
have also found that people suffering from low anxiety levels often demonstrate presence of an
overactive amygdale (Wetherell et al., 2004; Gallagher et al., 2008; Ruffault et al., 2017). Low
anxiety levels have also shown effects on information processing speed and attention. As there is
insufficient evidence there is need to do more research in this area to make it clearer. Thus, this
research will measure the effects of low anxiety levels on the aforementioned brain functions, as
it was not investigated in previous studies.
Increasing awareness of anxiety, its detrimental effects and benefits of diagnosis and
treatment are necessary for improving health and well being of the older and young adults.
Understanding the potential influence of anxiety in older people is essential for clinical
assessment, and diagnosis considering its potential for treatment. Very low levels of anxiety
might influence a variety of brain functions such as attention and information processing speed
Therefore, this research is valuable as deducing the relationship between the low level of anxiety
and brain functions. It will have valuable outcomes in studies with older adults. Such in-depth
investigation is imperative for gaining picture of research related to ageing, dementia and
cognitive impairment. Considering the research gaps related to affect of anxiety on different
brain functions, the primary aim of the research is justified which is to find association between
the speed of information processing and non-clinical anxiety levels, in relation to a plethora of

26THESIS SUMMARY
brain functions that encompass attention is justified. It includes visual attention, selective
attention, inhibitory cognitive control, intra-individual reaction time variability (IIVRT), reaction
time (RT) along with depression, sleep quality, and demographic parameters in young adults and
subjective and objective cognitive affect in older adults. By studying the wide range of brain
functions our knowledge of ageing process can be enhanced. Anxiety creates an impact on
memory. There is a separate literature that focused on different response of old young people to
positive and negative information respectively. A factor to be considered here is simple
stimulation effects due to consolidated sad memories. Low level of anxiety might also impact the
memory and other brain functions. This area has not been considered in previous research and
investigating the same may add to understanding the relation between anxiety, brain function,
and information processing. Therefore, the secondary aim of the research is to focus on valence
of memory.
The overall research process is the two phase study with primary aim being gaining a
sound understanding of the non-clinical anxiety among older and younger adults and its potential
impact on different brain functions, and the secondary aim being understanding the impact of
anxiety and memory. The two-phase organization of this study will allow gain sound knowledge
of the impact of the non-clinical anxiety and subjective and objective cognitive impairment as
well as relationship between the anxiety and sleep quality, information processing speed, and
attention in target group. There are many implications with the outcomes of this research such as
development of interventions for accurate case characterization of anxiety in dementia,
specifically, Alzheimer’ disease. If there is no direct relationship found between the anxiety and
different brain functions then the future studies may consider if causal effect lies in the alternate
direction.

27THESIS SUMMARY
Conclusion
The primary objective of this PhD research is to assess the relationship between the
information processing speed and non-clinical anxiety levels, among older and younger adults,
in relation to various brain functions that encompass attention, inhibitory cognitive control,
reaction time (RT) and intra-individual reaction time variability (IIVRT). The aim of the
literature review was to detect the research carried out in the field of anxiety and
memory/cognition.
It was evident from the literature review that there is lack of understanding and
knowledge of the ageing related information processing speed. The literature review showed that
there was lack of in-depth investigation of the non-clinical anxiety and associated information
pressing speed, as well as demographic parameters, and different aspects of the brain function.
The research gap due to lack of comprehensive neuropsychological method. There was but an
inconclusive data related to the impact of the anxiety levels and cognitive inhibition on the
subjective and objective cognitive function and on depression. There was an association found
between lowered anxiety and poor attention in older adults. However, there was insufficient data
in this regards among older adults with dementia. There was correlation between ageing and
decrease in sleep quality but not strongly correlated with anxiety as per previous studies. There
is lack of clarity in literature pertaining to relation between education and anxiety levels in
individuals. A greater association between the low education level and high anxiety levels and
depression was observed but it was not attributed to age group 65-74 years. There are fewer
studies to detect this relationship in older people with dementia and the impact on their
information processing speed and attention. Affect of sex on slowing of the information
processing speed, attention and IIV is not taken into consideration as a factor in many studies.

28THESIS SUMMARY
The data related to affect of handedness and vision on cognitive functioning and age related
decline such as SCF, OCF, and information processing speed remains controversial.
Most studies mainly focused on theoretical approaches and lacked the instruments needed
to define and diagnose the events associated with cognitive function in both clinical and research
domains. Therefore, the aim of this P.hD research is to use multi-methodological approach for
meeting the primary objective. The details of the individual parameters of brain function in
association with anxiety will be discussed in details in subsequent chapter.

29THESIS SUMMARY
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