Motor evoked potential studies in Creutzfeldt-Jakob disease

Objectives: Motor evoked potentials (MEPs) were recorded in 7 cases of Creu tzfeldt-Jakob disease (CJD) to asses the involvement of pyramidal motor pat hways in these cases. The diagnosis of CJD was confirmed by autopsy in 5 ca ses and based on clinical data in two cases. Methods: Transcranial (MEP-cortex), root magnetic (MEP-root) and electrical stimulation of peripheral nerves (F-wave, direct M-response) were performe d. The cortical excitability threshold, F-wave frequency, MEP amplitudes, p eripheral motor conduction velocity, standardized distal latencies and cent ral, loot, and F-wave conduction times were evaluated. Results: The results of MEP testing were markedly abnormal. Cortical excita bility thresholds were elevated, MEP amplitudes were reduced while the cond uction function was rather preserved. The features of functional disturbanc es and/or loss of upper and lower motor neurons were revealed. They correla ted with the advancement of key clinical CJD symptoms (progressive dementia , extrapyramidal and cerebellar signs, myoclonic jerks, mutism and typical periodic EEG changes), while motor lesion signs might only be slight or abs ent. Conclusions: Conduction slowing, if present, seemed to be secondary to axon al lesion. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.