Multifocal slowing of nerve conduction research in polyneuropathy

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Abstract from Muscle Nerve. 2004 Apr;29(4):531-6. (Mentions CMT Type X)

Multifocal slowing of nerve conduction in metachromatic leukodystrophy.

Cameron CL, Kang PB, Burns TM, Darras BT, HR Jr.

Department of Neurology, Lahey Clinic, 41 Mall Road, Burlington,

Massachusetts 01805, USA.

Polyneuropathy is invariably associated with the late-infantile form of

metachromatic leukodystrophy (MLD), and occurs frequently in the early

juvenile, juvenile, and adult variants. Uniform slowing of nerve

conduction velocity is the neurophysiologic hallmark of metachromatic

leukodystrophy and other inherited demyelinating polyneuropathies. To

evaluate the consistency of this principle, we reviewed nerve conduction

studies in 9 children with late-infantile or early-juvenile

metachromatic leukodystrophy. Each child had significant slowing of

motor nerve conduction velocity (NCV). The compound muscle action

potentials showed abnormal temporal dispersion in 3 of the 9 children,

which is usually regarded as the hallmark of acquired demyelinating

polyneuropathies. There are reports of multifocal slowing in other

hereditary processes including X-linked Charcot-Marie-Tooth disease,

hereditary neuropathy with liability to pressure palsies, and

adrenomyeloneuropathy. Although multifocal NCV slowing in a child with

polyneuropathy is seen most commonly in acquired conditions, a

hereditary process, including MLD, cannot always be excluded in this

setting.