TY - JOUR
T1 - Corticomotoneuronal function in asymptomatic SOD-1 mutation carriers
AU - Vucic, Steve
AU - Winhammar, Jennica M C
AU - Rowe, Dominic B.
AU - Kiernan, Matthew C.
PY - 2010
Y1 - 2010
N2 - Objective: Diffusion tensor imaging (DTI) recently identified structural abnormalities of corticomotoneurons in asymptomatic copper/zinc superoxide-dismutase-1 (SOD-1) gene mutation carriers. The potential existence of longstanding corticomotoneuronal dysfunction would clearly have consequences for the medical management of asymptomatic SOD-1 mutation carriers. To clarify this unexpected finding, DTI techniques were combined with threshold tracking transcranial magnetic stimulation (TMS) to assess the anatomical and functional integrity of corticomotoneurons in asymptomatic SOD-1 mutation carriers. Methods: TMS studies were undertaken using a 90 mm circular coil on seven asymptomatic SOD-1 mutation carriers and results were compared to 62 healthy controls. DTI studies were carried out using a 3 T magnetic resonance device in the same asymptomatic SOD-1 mutation carriers. Results were compared to age-matched healthy controls. Results: In contrast to previous findings, there were no significant differences in fractional anisotropy (SOD-1 mutation carriers, 0.62 ± 0.01; controls, 0.61 ± 0.02, P= 0.2) and trace apparent diffusion coefficient (SOD-1 mutation carriers, 0.003 ± 0.0001; controls, 0.003 ± 0.0001) in asymptomatic SOD-1 mutation carriers. Of further relevance, there were no significant differences in short-interval intracortical inhibition (SOD-1 mutation carriers, 7.9 ± 3.4%; controls, 8.5 ± 1.1%, P= 0.26), intracortical facilitation (P= 0.5), MEP amplitude (P= 0.44), resting motor threshold (P= 0.36) and cortical silent period duration (P= 0.29). Conclusions: Combined anatomical and functional modalities established normal integrity of corticomotoneurons in asymptomatic SOD-1 mutation carrier subjects. Significance: Additional factors other than simply SOD-1 mutation expression are required to trigger cortical hyperexcitability and neurodegeneration in FALS.
AB - Objective: Diffusion tensor imaging (DTI) recently identified structural abnormalities of corticomotoneurons in asymptomatic copper/zinc superoxide-dismutase-1 (SOD-1) gene mutation carriers. The potential existence of longstanding corticomotoneuronal dysfunction would clearly have consequences for the medical management of asymptomatic SOD-1 mutation carriers. To clarify this unexpected finding, DTI techniques were combined with threshold tracking transcranial magnetic stimulation (TMS) to assess the anatomical and functional integrity of corticomotoneurons in asymptomatic SOD-1 mutation carriers. Methods: TMS studies were undertaken using a 90 mm circular coil on seven asymptomatic SOD-1 mutation carriers and results were compared to 62 healthy controls. DTI studies were carried out using a 3 T magnetic resonance device in the same asymptomatic SOD-1 mutation carriers. Results were compared to age-matched healthy controls. Results: In contrast to previous findings, there were no significant differences in fractional anisotropy (SOD-1 mutation carriers, 0.62 ± 0.01; controls, 0.61 ± 0.02, P= 0.2) and trace apparent diffusion coefficient (SOD-1 mutation carriers, 0.003 ± 0.0001; controls, 0.003 ± 0.0001) in asymptomatic SOD-1 mutation carriers. Of further relevance, there were no significant differences in short-interval intracortical inhibition (SOD-1 mutation carriers, 7.9 ± 3.4%; controls, 8.5 ± 1.1%, P= 0.26), intracortical facilitation (P= 0.5), MEP amplitude (P= 0.44), resting motor threshold (P= 0.36) and cortical silent period duration (P= 0.29). Conclusions: Combined anatomical and functional modalities established normal integrity of corticomotoneurons in asymptomatic SOD-1 mutation carrier subjects. Significance: Additional factors other than simply SOD-1 mutation expression are required to trigger cortical hyperexcitability and neurodegeneration in FALS.
UR - http://www.scopus.com/inward/record.url?scp=77956121296&partnerID=8YFLogxK
U2 - 10.1016/j.clinph.2010.02.164
DO - 10.1016/j.clinph.2010.02.164
M3 - Article
C2 - 20362497
AN - SCOPUS:77956121296
SN - 1388-2457
VL - 121
SP - 1781
EP - 1785
JO - Clinical Neurophysiology
JF - Clinical Neurophysiology
IS - 10
ER -