Cortical silent period prolongation in spinocerebellar ataxia type 2 (SCA2).
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disorder mapped on chromosome 12. Different results have been reported in spinocerebellar ataxias following transcranial magnetic stimulation (TMS). TMS-induced cortical silent period (CSP) was prolonged in different cerebellar disorders. Here we evaluate the duration of the TMS-induced CSP following a single magnetic stimulus in a large homogeneous group of SCA2 patients compared with idiopathic cerebellar ataxia (IDCA) patients with similar disease duration and severity, and in 20 healthy controls. The CSP duration in both arm and leg muscles was significantly (p<0.005) longer in patients than in controls. A significant positive correlation between disease duration and CSP prolongation in both SCA2 and IDCA was found. No correlation between age, onset and CSP duration emerged in either group. This study shows a prolongation of the TMS-induced silent period in both SCA2 and IDCA indicating that the cortical inhibitory mechanism is dependent on the disease duration and severity. Thus, the cerebellum seems to exert a pliable physiological influence on the cortico-spinal system through control of inhibitory cortical interneurons.
Restivo
Domenico A
DA
Department of Neurology, Garibaldi Hospital, Catania, Italy.
Lanza
Sara
S
Giuffrida
Salvatore
S
Le Pira
Francesco
F
Drago
Maria Teresa
MT
Di Mauro
Rosario
R
Palmeri
Agostino
A
Puzzo
Daniela
D
Puzo
Daniela
D
Di Bella
Paolo
P
Sessa
Edoardo
E
Rifici
Carmela
C
D'Aleo
Giangaetano
G
Muscarà
Nunzio
N
Bramanti
Placido
P
D000328:Adult; D000368:Aged; D002524:Cerebellar Ataxia / Q000503:physiopathology*; D004056:Differential Threshold; D004558:Electric Stimulation / Q000379:methods; D004574:Electromagnetic Fields; D004576:Electromyography; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009431:Neural Conduction; D009433:Neural Inhibition; D020754:Spinocerebellar Ataxias / Q000503:physiopathology*; D013997:Time Factors