SOMATOSENSORY-EVOKED POTENTIALS AND INTRACRANIAL-PRESSURE DURING CHRONIC DILATATION OF AN ARTIFICIAL EXTRAPARENCHYMAL SPACE-OCCUPYING LESION IN CATS

Somatosensory evoked potentials (SEP) and intracranial pressure (ICP) were studied in cats, suffering from a chronic space-occupying lesion produced by enlargement of an epidural balloon over the left sensomoto ry cortex. Our study shows that latency alterations of SEP are not dep endent on the degree of ICP. Additionally, the results obtained demons trate that chronic space-occupying lesions cause continuous prolongati on of SEP latencies, probably produced by atrophy of the compressed ti ssue. Regarding the clinical importance of SEP measurements, we conclu ded that they are not suitable for estimating the degree of ICP. Howev er, they are useful to evaluate tissue damage caused by mass effects i n the acute and chronic phase of various space-occupying processes.