Neurophysiological correlates of senile dementia: II. The somatosensory evoked response

Abstract

SYNOPSISSpecific cortical somatosensory evoked responses were recorded in nine patients suffering from senile dementia and eight elderly depressed patients. The results were as follows. (1) The latencies of each peak were longer in the demented than in the depressed group but this difference was significant only for peak 3 (the second negative deviation). (2) The late negative deviation (peak 5) was either absent or very flat in demented patients. The ratio of the amplitude of this late wave to that of the first peak discriminated between demented and non-demented patients at the 0·5% level. (3) The value of this ratio combined with that of the latency of peak 3 could be used to classify all but one patient into the correct diagnostic group. The results are discussed in the light of the relevant literature. It is suggested that slowing of conduction in the nervous system may be a very basic disturbance associated with cognitive impairment in old age and that measurements of this kind may come to assist in the diagnosis of dementia.

Multichannel EEG Frequency Analysis and Somatosensory-Evoked Potentials in Patients with Different Types of Organic Dementia

“…Levy et al [28] recorded somatosensory-evoked re sponses with a bipolar montage and reported the negative peak around 40 ms to be delayed in senile dementia. Since then, the different components of somatosensoryevoked responses have been more properly identified with multichannel referential recordings [29].…”

Event-related potential validators in Alzheimer's disease.

“…Visser, Stam, and Van Tilburg (1976) confirmed this. Levy, Isaacs, and Behrman (1971) found latency prolongations and N1 amplitude reduction in senile dementia. Hendrickson, Levy, and Post (1979) also found some midlatency ERP prolongation in senility.…”