Abstract
Short latency somatosensory evoked potentials (SSEPs) were recorded in 16 comatose patients 3.19 +/- 1.67 (mean +/- SD) days after the onset of a cerebrovascular accident. The SSEP, Glasgow Coma Scale (GCS) and Glasgow Outcome Score (GOS) results were compared. The SSEP, in all patients with low SSEP grades, indicated an unfavourable outcome: 43.8% dead, 8.3% vegetative state and 25% severely disabled. Patients with good SSEP grades had a favourable outcome, 23% with moderate to good recovery. The SSEP findings correlated well with GCS scores at either end of the extremes of scale (GCS score of 3-14). Patients with high GCS score of 14 had high grades of both SSEP and P14. In contrast, those with low GCS score of 3 had low SSEP and P14 grades. There was a significant correlation between SSEP grades and GCS scores (rs = 0.60; P < 0.050). We found a very high correlation between SSEP grades and GOS (rs = 0.91; P < 0.01). All patients with an unfavourable score (n = 11) had poor SSEP grades (1-3). In contrast, GCS scores had insignificant correlation with Glasgow functional outcome (rs = 0.11; P < 0.1). The P14 (lemniscus medialis potential) had a significant moderate correlation with total outcome (rs = 0.60; P < 0.05). P14 was absent in six patients whose EEG was isoelectric and fitted with the clinical criteria of brainstem death. We conclude that the SSEP grading system in comatose patients has significant quantitative and prognostic value in those with strokes. P14 is important in identifying brainstem death. Applying these criteria of electrophysiological studies, the outcome for comatose patients could be classified to strengthen clinical evaluation. (C) 1998 Chapman & Hall Ltd.