title: Cerebellar dysfunction in progressive supranuclear palsy: a transcranial magnetic stimulation study.
abstract: Progressive supranuclear palsy (PSP) rarely shows cerebellar signs and symptoms even though the cerebellar dentate nuclei are involved pathologically. This study evaluates cerebellar function using transcranial magnetic stimulation (TMS) to determine whether subclinical cerebellar involvement is present in PSP patients. We studied 11 patients with PSP, 11 patients with Parkinson's disease (PD), and 10 age-matched controls. Patients were examined with their usual medications and in their relative on state. Motor evoked potentials (MEPs) were recorded from the hand muscle. Cerebellar function was evaluated using suppressive effects of TMS over the cerebellum on MEPs elicited by TMS over the contralateral motor cortex, which we call cerebellar inhibition (CBI). Interstimulus intervals (ISIs) of 4 to 8 ms were used, and the time course of CBI was analyzed. The CBI was reduced in PSP patients. By contrast, the CBI was normal in PD patients in their on state. Although the CBI in their off state should be examined in future studies, the results described herein suggest that Purkinje cells or the dentato-thalamo-cortical pathway assessed by CBI is involved in PSP. Our results are compatible with the pathological findings showing severe dentate nucleus degeneration in PSP patients.
authors.affiliation: Department of Neurology, Division of Neuroscience, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. yshirota-tky@umin.ac.jp
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Shirota
authors.forename: Masashi
authors.initials: M
authors.lastname: Hamada
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Hanajima
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terao
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Ohminami
authors.forename: Shoji
authors.initials: S
authors.lastname: Tsuji
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D002526:Cerebellar Diseases / Q000209:etiology*; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006225:Hand / Q000294:innervation; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D011930:Reaction Time / Q000502:physiology; D012720:Severity of Illness Index; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013494:Supranuclear Palsy, Progressive / Q000150:complications*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation