Glasgow Coma Scale: Components, Scoring, and Clinical Implications

Structure of the Scale

• The Glasgow Coma Scale (GCS) comprises three independent assessment categories—eye opening, best motor response, and best verbal response—whose scores are summed to a total ranging from 3 (deep coma or death) to 15 (fully awake)【1】.

Scoring Details

Eye‑Opening Response (1–4 points)

These definitions are derived from the original GCS description【1】.

Best Verbal Response (1–5 points)

Based on the standard GCS verbal component criteria【1】.

Best Motor Response (1–6 points)

These motor response grades follow the conventional GCS motor scoring system【1】.

Exclusions from the GCS

• Peripheral reflexes are explicitly excluded from the GCS assessment; brainstem reflexes (e.g., pupillary light, corneal, oculovestibular) are separate clinical findings that remain essential for neurological prognostication, particularly after cardiac arrest【2】.

Clinical Predictive Value

• The motor component is the strongest predictor of neurological outcome, especially in intubated patients where verbal assessment cannot be performed【3】.
• For optimal clinical communication, the GCS should be reported by its three individual components (E‑V‑M) rather than solely as a summed total, providing more granular information for patient management【3】.

Guidelines for Glasgow Coma Scale Documentation in Motor (Broca’s) Aphasia

Documentation Practices

• Record the full Glasgow Coma Scale (GCS) using the three individual components—Eye (E), Verbal (V), and Motor (M)—and explicitly note “motor aphasia present” when the patient has a language production deficit. 4
• Score the verbal response according to the patient’s actual output: incomprehensible sounds = V2; inappropriate words = V3; confused or disoriented speech = V4. 4
• Include a separate statement in the clinical note indicating the presence of aphasia (e.g., “GCS 13 (E4 V4 M5), motor aphasia present”). 5

Monitoring Frequency and Trend Interpretation

• Perform GCS assessments every 15 minutes for the first 2 hours, then hourly for the subsequent 12 hours in patients with moderate‑to‑severe motor aphasia. 5
• A decline of ≥ 2 points in the total GCS score should prompt an immediate repeat head CT to evaluate for new or worsening intracranial pathology. 5

Prognostic Value of GCS Components

• The motor component (M) retains the highest predictive value for outcome and remains robust even when the verbal component is affected by aphasia. 5

Additional Neurological Documentation

• At each GCS assessment, document pupil size and reactivity, as these are independent prognostic indicators of neurological status. 5