Pp. Urban et al., IMPAIRED CORTICO-BULBAR TRACT FUNCTION IN DYSARTHRIA DUE TO HEMISPHERIC STROKE - FUNCTIONAL TESTING USING TRANSCRANIAL MAGNETIC STIMULATION, Brain, 120, 1997, pp. 1077-1084
We investigated cortico-lingual and cortico-orofacial tract function u
tilizing transcranial magnetic stimulation in 18 consecutive patients
with dysarthria due to hemispheric stroke. Delayed responses (conducti
on time > mean + 2.5 SD of that of 43 controls) or absent responses we
re considered abnormal. In all patients, motor-cortex stimulation of t
he lesion side demonstrated absent (13 patients) or delayed (five pati
ents) responses to the tongue bilaterally (17 patients) or unilaterall
y (one patient). In 14 patients the contralateral orofacial responses
were either absent (13 patients) or delayed (one patient). According t
o the electrophysiological findings, all lesions revealed by CT or MRI
, were located within the pyramidal tract at the lower motor cortex (n
= 4), the corona radiata (n = 7), and the genu of the internal capsul
e (n = 3) or its posterior limb (n = 4). We conclude that interruption
of the cortico-bulbar tract fibres to muscles involved in articulatio
n is a frequent cause of dysarthria in hemispheric stroke.