Article

Dystonia in childhood has many causes. Imaging may suggest corticospinal
tract dysfunction with or without coexistent basal ganglia damage. There are very
few published neurophysiological studies on children with dystonia; one previous
study has focused on primary dystonia. We investigated central motor conduction
in 62 children (34 males, 28 females; age range 3-19y, mean age 10y 8mo, SD 4y
8mo) with severe dystonia to evaluate corticospinal tract integrity before
consideration for deep brain stimulation. METHOD: Distal motor and F-wave
latencies were measured in the ulnar and/or posterior tibial nerves. Transcranial
magnetic stimulation was applied over the motor cortex and motor-evoked
potentials were recorded in the activated abductor digiti minimi and/or abductor
hallucis muscles. Central motor conduction time (CMCT) was calculated using the
F-wave method. RESULTS: CMCT was normal in 50 out of 62 patients; 12 patients
showed prolonged CMCT to upper and/or lower limbs. Most children with severe
primary and secondary dystonia had normal CMCT, indicating corticospinal tract
integrity despite abnormal imaging in 42 out of 50 patients. Abnormal CMCT was
found in two out of 12 patients with normal imaging. INTERPRETATION: This study
provides new CMCT data for children with severe primary and secondary dystonia.
Over 50% of children with evidence of periventricular white-matter damage from
magnetic resonance imaging had normal CMCT, challenging traditional
pathophysiological models. This is consistent with recent diffusion tensor
imaging in children with periventricular white-matter damage, showing disruption
of sensory connections rather than corticospinal tract damage. CMCT helps refine
our understanding of imaging changes in complex motor disorders of childhood.
CI - (c) The Authors. Developmental Medicine & Child Neurology (c) 2011 Mac Keith
Press.

Langue : ANGLAIS