Prediction of secondary deterioration in comatose neurosurgical patients by serial recording of multimodality evoked potentials

In 75 comatose neurosurgical patients suffering from various types of intracranial lesions, multimodality evoked potentials (auditory, somatosensory, visual) were serially recorded at short intervals in order to evaluate their usefulness for early detection of secondary deterioration in the clinical course. The best parameter for prediction of secondary deterioration (as estimated by pupillary status) was a diminution in amplitude or disappearance of the primary cortical SEP peak. Considering these parameters, sensitivity of the prediction of pupillary behaviour was 71%, specificity 84%. Additional consideration of SEP latencies or BAEP or VEP parameters did not further increase the efficacy of prediction. In cases of correct positive prediction, deterioration of SEP occurred 4 to 144 hours before the deterioration of pupillary physiology.