Motor cortex excitability in transient global amnesia.
OBJECTIVE
To investigate the physiology of motor cortical areas in patients with transient global amnesia (TGA).


METHODS
We performed transcranial magnetic stimulation (TMS) and single photon emission computed tomography (SPECT) in 13 patients during and after the acute phase of a typical episode of TGA. Measures of cortical excitability included motor threshold (MT) to magnetic stimulation, cortical silent period (SP) duration and intracortical inhibition (ICI) using a paired-pulse TMS technique.


RESULTS
We found thalamic hypoperfusion and an ipsilateral significantly decreased ICI during the acute phase of TGA.


CONCLUSIONS
Reduced activity in inhibitory circuits may explain why PET studies of patients with TGA showed neocortical hypometabolism. Our findings are consistent with the hypothesis that frontal cortex dysfunction probably due to damage affecting the thalamocortical circuits may play an important role in the pathogenesis of the syndrome.
Dept. of Neurology, F. Tappeiner Hospital, Via Rossini 5, 39012 Merano, BZ, Italy. raffaele.nardone@asbmeran-o.it
Raffaele
R
Nardone
Ebba C
EC
Buffone
Massimo F
MF
Matullo
Frediano
F
Tezzon
D000328:Adult; D000368:Aged; D020236:Amnesia, Transient Global / Q000503:physiopathology*; D000704:Analysis of Variance; D016022:Case-Control Studies; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology* / Q000528:radiation effects; D009431:Neural Conduction / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D009483:Neuropsychological Tests; D011930:Reaction Time; D012684:Sensory Thresholds / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods