Comprehensive Analysis of Glasgow Coma Scale Validity and Reliability

This report provides a detailed analysis of the Glasgow Coma Scale (GCS), a critical clinical assessment tool used to evaluate the level of consciousness in patients, particularly those with traumatic brain injuries. The report begins by outlining the context for the GCS's development, its significance in assessing patients in the Intensive Care Unit (ICU) and emergency departments, and the clinical role of registered nurses in utilizing this tool. The core of the report assesses the validity and reliability of the GCS, including inter-rater reliability, test-retest reliability, internal consistency, criterion validity, construct validity, sensitivity, and predictive value. It draws upon a range of studies to evaluate the GCS's effectiveness, discussing kappa statistics, agreement rates, and correlations. The report also addresses the limitations of the GCS, such as inconsistencies and challenges in assessing intubated patients. The discussion synthesizes the findings, emphasizing the GCS's reliability and its role in guiding early patient management and monitoring, while also acknowledging the influence of factors like alcohol intoxication or medication on GCS scores. The conclusion highlights the GCS's widespread use, its reliability as a tool for assessing the initial and subsequent levels of consciousness, and its integration into various guidelines and assessment scores used in healthcare.

Running head: CLINICAL ASSESSMENT
Analysing the Validity and reliability of the Glasgow Coma Scale
Name of the Student
Name of the University
Author Note

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Analysing the Validity and reliability of the Glasgow Coma Scale
My patient population and clinical role
As registered nurses working in the Intensive Care Unit and emergency department,
our team has to experience several cases of severe brain injuries in adults and children. Such
patients are admitted with neurological deficit, amnesia, seizure, and altered levels of
consciousness and the workers are required to assess their health with the help of an
instrument.
The assessment tool and the context for its development
An instrument used by healthcare professionals to evaluate the clinical condition of
the patient with a set of measurements is known as a clinical assessment tool (Guan &
Ghogawala, 2019). Such tools can be presented as a checklist, questionnaire, or scale. It is
essential to analyze the validity and reliability of a clinical assessment tool, as they are
critical to determining the prognosis and treatment strategies for the patient. The Glasgow
Coma Scale was designed by Graham Teasdale and Bryan J. Jennet, in 1974 to assess the
consciousness levels of the patient and can be used in traumatic brain injuries by trained
medical professionals.
The following sections of the paper will evaluate the validity and reliability of the
Glasgow Coma Scale, a neurological scale that measures the consciousness levels of the
patient and determines its overall efficiency and clinical importance (Sedain & Bhusal, 2019).
Assessing Validity and reliability of GCS
The evaluation of confused patients is a significant part of primary consideration.
Tragically, there is no target proportion or evaluation criteria of coma state like temperature
or circulatory strain. In this way, so far, the evaluation of the degree of coma state needs to
depend on clinical scores assessed by the healthcare experts. The Glasgow Coma Scale
(GCS), initially intended for patients with a head injury, has developed into the most broadly

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utilized scoring framework for patients with a changed degree of awareness in the ICU.
Significant impediments of the GCS incorporate conflicting between unwavering onlooker
qualities, worries over the prescient incentive in cerebrum injury patients experiencing
present-day neuro-concentrated consideration, the difficulty of surveying the intubated
patient’s verbal score, and the avoidance of brainstem reflexes.
Inter-rater reliability
A systematic review of literature conducted by Reith et al. (2016), reviewed 52
studies to determine the validity and reliability of the Glasgow Coma Scale. Out of this, 32
studies reported 265 individual kappa statistics. The excellent and fair-quality studies
reported kappa values of 85% and 86%, respectively, which correlates to substantial
reliability. On the other hand, the poor quality studies reported that 56 % of the kappa’s to be
≥0.6. For the studies focussed in ICU care settings, 90.5 % of kappas were ≥0.6.
Another set of researchers, Kirschen et al. (2019), conducted a prospective
observational study to determine inter-rater reliability. The overall percent agreement
between study 91% for the verbal, 89% for the eye, and 79% for the motor responses. The
Inter-rater reliability ranged from excellent (intraclass correlation coefficient = 0.96) to good
(intraclass correlation coefficient = 0.75) for testable clients. For children with developmental
disabilities, the agreement rate on motor responses were significantly lower ( ≥ 2 yr: 55% vs
91%; p = 0.0012 and < 2 yr: 59% vs 95%; p = 0.0012).
The inter-rater understanding of the nervous system specialists was rarely more
terrible and mostly altogether improved than that of the ICU staff. Nonetheless, to the extent
exactness in scoring inside the scope of ± 1 score focuses is concerned, the ICU staffs
equaled nervous system specialists. This finding demonstrates that the accuracy in
neurological scoring adequate for the clinical settings accomplished by general ICU staff,

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which cannot be altogether improved by committed pros from outside the Intensive Care
Units.
Test-retest Reliability
An interview-based study conducted by Bogner et al., (2017), aimed at reviewing the
test-retest reliability of measures of several scales, including GCS. Relatively high prevalence
indices (>0.80), which can subdue kappa, were found for psychiatric hospitalization, arrested,
residence, congestive heart failure, suicide attempt, myocardial infarction, cancer, stroke,
and liver disease before the age of 15 years. Intraclass correlation coefficient esteems
extended from 0.65 to 0.99, weighted kappa esteems went from 0.54 to 0.99, and kappa
esteems ran from 0.43 to 1.00. Four kappa/weighted kappa gauges fell beneath 0.60:
captured, mental hospitalization, total number of days not in great physical wellbeing, and
rating of general passionate wellbeing.
Internal Consistency
From the research article published by Reith et al. (2016), the six values determined
from significant quality examinations, 100 % are over 0.80, proposing remarkable interior
consistency. Comparative outcomes are found in reasonable quality examinations, yet the
low-quality investigations show somewhat less favorable outcomes (60 % >0.80).
Criterion Validity
According to Ting et al. (2010), the predictive/concurrent validity of GCS applicable
for patients in ICU was GCS score < 5= 50% mortality rate, which is considerably higher rate
than those with GCS >5 (p<0.01). GCS-Verbal scores and GCS-Eye opening of 1 had a
higher probability of death than clients with scores > 1 (p< 0.01). Furthermore, GCS-Motor
score ≤ 3 had a greater probability of death than clients with a GCS-M >3 (p< 0.01).

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However, according to Balestreri et al. (2004), the predictive validity of the GCS
scale is questionable in predicting the outcome scores, as it fluctuated between weak and
adequate correlations.
Another study conducted by revealed that the area under the curve for the GCS was
0.77 (95% CI = .64Y.87) for in-hospital mortality.
Construct Validity
A study conducted by Amirjamshidi et al. (2006) stated the construct validity of the
GCS applied for chronic subdural hematoma as adequate, as the correlations between GCS
(Glasgow Coma Scale) and the GOS (Glasgow Outcome Scale) was r = 0.557. Another study
conducted by Shanmuganathan et al. (2004) marked the construct validity of the scale when
applied for a head injury as adequate, with the correlation between coefficient histogram
values of whole-brain apparent diffusion and GCS score (r squared = .67).
Sensitivity
A research study conducted by Baratloo et al. (2016) with cross-sectional prospective
study design, measured the specificity and sensitivity of the GCS in predicting adverse
outcomes were 88.6% and 84.2% at the point of admission, 95.4% and 89.5% at the sixth
hour and 91.5% and 89.5% at the twelfth hour. The data picked up from the three parts of the
Scale differs over the range of receptiveness. Changes in reaction are the dominating element
in more seriously hindered patients, while eye and verbal are progressively valuable in lesser
degrees. The all out score imparts a helpful outline in the general file, however, with some
loss of data.
Components like liquor inebriation, medication use, or low blood oxygen can alter a
patient's degree of awareness. These elements could prompt a mistaken score on the GCS.

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Predictive Value
A cross-sectional study conducted by Nik et al. (2018), aimed at evaluating the
efficacy of the GCS scale in comparison to APACHE II (Acute Physiology and Chronic
Health Evaluation Score II). Positive predictive value (PPV) at the cut-off focuses was higher
in APACHE II (80.6%) contrasted to GCS (69.2%). Nonetheless, negative prescient worth
(NPV) of GCS was somewhat higher in comparison with APACHE II. In addition, the region
under the collector working trademark (ROC) bends for affectability and explicitness of GCS
and APACHE II demonstrated no noteworthy contrast (0.81±0.04 versus 0.83±0.04; p=0.278
individually).
Discussion
The reliability of the GCS scoring framework has been assessed in various
investigations with different outcomes relying upon sorts of patients, qualities of clinical
suppliers, and the clinical situations examined. Most investigations in grown-ups found at
least a moderate degree of between rater understanding, with enhancements dependent on
eyewitness understanding, preparing, and instruction
The reliability of the GCS Scale has experienced broad investigation. Even though its
reproducibility has been addressed in few reports, these have ended up being exceptional
cases. Thus, it is inferred that 85% of the discoveries in more excellent investigations
demonstrated generous unwavering quality as decided by the standard measure of a kappa
measurement (k) above 0.6. The reproducibility of the all-out GCS Score was likewise high,
with kappa more prominent than 0.6 in 77 % of perceptions. A reasonable advantageous
impact on unwavering quality came about because of instruction and preparation. To advance
this activity, a traditional organized way to deal with appraisal has been set out.
The discoveries from the Bogner et al. (2017) study was that to bolster the end; a
dependable self-report can be gotten from people with moderate-serious TBI utilizing the

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measures and follow-up technique utilized by the TBIMS. With barely any individual cases,
these measures used to assess results at follow-up meet regular benchmarks for "great" or
"significant" reliability quality—besides, the dependability figures acquired with this
example contrast moderately well and those of different investigations. Comparative
functional examinations were established with different investigations of a progressively
select arrangement of factors. The particular case was a lower coefficient for the DRS
(Disability Rating Scale); be that as it may, the example size for the earlier investigation was
significantly low (n = 40), and the strategy for organization contrasted (Bogner et al., 2017).
A connection between evaluations of the GCS (commonly revealed as the all-out GCS
Score) and the result was indicated by Gennarelli et al. (1994) who exhibited the presence of
a nonstop, dynamic relationship between expanding mortality after a head injury and
diminishes in Glasgow Coma Scale Score from 15 to 3. This affiliation has been seen in
numerous other consequent examinations. The discoveries for the eye, verbal and motor
reactions likewise identify with the result yet in unmistakable manners, so evaluation of each
independently yields more data than the total absolute score.
Nonetheless, even though it is one of the most remarkable clinical prognostic
highlights, neither the GCS scores nor any single component alone ought to be utilized to
foresee a single patient's result. This is because the prognostic ramifications of the score are
impacted by a few elements. These incorporate the conclusion, age and other clinical lists,
(for example, pupillary brokenness and imaging discoveries), the GCS score is a crucial
segment of multifactorial models for the expectation of results, for example, in the IMPACT
and CRASH preliminaries.
Evaluation of sensitivity with the Glasgow Coma Scale is broadly used to direct early
administration of patients with a head injury or other sort of intense cerebrum injury. Choices
in more seriously impeded patients incorporate rising administration, for example, tying

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down the aviation route and triage to decide quiet exchange. Choices in less severely disabled
patients incorporate the requirement for neuroimaging, affirmation for perception, or release.
Sequential Glasgow Coma Scale evaluations are likewise fundamental in checking the
medical course of a patient and controlling changes in the executives.
In both verbal and preverbal pediatric patients, the GCS is a precise marker for
clinically significant awful mind injury (i.e., an injury needing neurosurgical mediation,
intubation for more than 24 hours, requiring hospitalization for over two evenings, or causing
death.
The GCS has been taken into various rules and evaluation scores. These incorporate
injury rules Brain Trauma Foundation (severe TBI rules), Advanced Trauma Life Support,
Advanced Cardiac Life Support and concentrated consideration scoring frameworks
(APACHE II, SOFA).
Conclusion
The Glasgow Coma Scale (GCS) is the most well-known scoring framework used to
depict the degree of cognizance in an individual after a horrendous mind injury. Primarily, it
is utilized to help measure the seriousness of an intense cerebrum injury. The test is
straightforward, dependable, and connects well with the result following extreme mind
injury.
The GCS is a dependable and target method for recording the underlying and
consequent degree of awareness in an individual after a mind injury. It is utilized via prepared
staff at the site of a physical issue like a fender bender or sports injury, for instance, and in
the crisis office and concentrated consideration units.
The overall reliability that can be adjudged from the data in the above sections of the
paper is ‘adequate’. However, ‘adequate’ certainly refers to the issue that the scaling

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measures is not highly effective and requires modifications to get to higher standards of
clinical monitoring tools.

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