Afferent and efferent excitabilities of the transcortical loop in patientswith dentatorubral-pallidoluysian atrophy

Citation
T. Touge et al., Afferent and efferent excitabilities of the transcortical loop in patientswith dentatorubral-pallidoluysian atrophy, J NEUR SCI, 176(1), 2000, pp. 28-36
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences & Behavoir
Journal title
JOURNAL OF THE NEUROLOGICAL SCIENCES
ISSN journal
0022-510X → ACNP
Volume
176
Issue
1
Year of publication
2000
Pages
28 - 36
Database
ISI
SICI code
0022-510X(20000501)176:1<28:AAEEOT>2.0.ZU;2-S
Abstract
To evaluate the excitabilities of the transcortical loop in patients with d entatorubral-pallidoluysian atrophy (DRPLA), we studied somatosensory evoke d potentials (SEPs) and evoked EMG responses (V1 and V2) in 10 patients and age-matched controls. In addition, the facilitatory effects of somatosenso ry inputs on motor evoked potentials (MEPs) were studied in four patients a nd controls. We observed attenuated or prolonged cervical and subcortical p otentials and prolonged middle latency components of SEPs. The amplitudes o f V2 in patients were significantly lowered compared to those in the contro ls, while the amplitudes and latencies of V1 were similar between the two g roups. Since V2 was considered as a transcortical reflex, our results sugge st reduced excitabilities of the afferent pathway of the transcortical loop in patients with DRPLA. Median nerve stimulation (MNS) 25 to 30 ms precedi ng transcranial magnetic stimulation (TMS) facilitated MEPs in the thenar m uscle in two of the four patients and in the controls. The facilitation of MEPs by MNS tended to be independent of the reduction in V2. Such a result suggests that different neural mechanisms elicit V2 and facilitate MEPs fol lowing peripheral nerve stimulation, although further studies are needed. T he combination of SEPs, evoked EMG responses and MEPs may be a useful techn ique to detect abnormalities of input and output coordinations of the trans cortical loop. (C) 2000 Published by Elsevier Science B.V.