SOMATOSENSORY-EVOKED POTENTIALS WITH HIGH CORTICAL AMPLITUDES - CLINICAL-DATA IN 31 CHILDREN

Between 1989 and 1993, somatosensory evoked potentials (SEP) were reco rded as part of the diagnostic work-up in 282 children with different neurologic disorders. In thirty-one children the N20/P25/N35 amplitude s were enhanced compared to our control group (highest amplitude 14.1 muV). Four children had amplitudes > 40 muV (''giant''), fifteen betwe en 20-39.9 muV (''elevated'') and twelve between 14-19.9 muV (borderli ne''). Enhanced cortical SEPs were seen in all patients with neuronal ceroid lipofuscinosis (5 late-infantile NCL > 20 muV, 1 juvenile NCL 1 4.7 muV). In addition, five of six NCL children showed bilaterally pro longed cervico-cortical conduction times, otherwise only seen in a 4-m onth-old child following hypoxia. ''Borderline'' and ''elevated'' SEPs occurred in patients with heterogeneous neurologic disorders. Follow- up recordings showed inconsistent results: seven children had amplitud es > 14 muV in all recordings, six only at the first examination, and six only at follow-up. In six children with hemiparesis enhanced SEPs were recorded over both (n = 2) or only over the unaffected hemisphere (n = 4). Myoclonic seizures were observed only m five children with N CL. Similar to other SEP parameters, enhanced amplitudes are an unspec ific indicator of an ongoing neurologic disorder. However, in neuronal ceroid lipofuscinosis, enhanced SEP amplitudes may be a useful diagno stic criterium.