Subclinical sensory involvement in monomelic amyotrophy

Area of Science:

• Neurology
• Neurophysiology

Background:

• Monomelic amyotrophy (MA) is a rare neuromuscular disorder characterized by focal muscle wasting and weakness.
• Classic MA presentations involve only motor neuron deficits, with no sensory abnormalities reported.

Purpose of the Study:

• To investigate potential subclinical sensory nerve involvement in a patient with a classic presentation of monomelic amyotrophy.

Main Methods:

• Case report of an 18-year-old woman with hand weakness and atrophy.
• Clinical neurological examination to assess sensory and motor function.
• Electrophysiological studies, including nerve conduction studies, comparing affected and unaffected limbs.

Main Results:

• The patient exhibited typical motor findings consistent with monomelic amyotrophy.
• Electrophysiological studies revealed significantly reduced sensory nerve action potentials in the affected limb compared to the unaffected limb.
• No sensory deficits were detected during the clinical neurological examination.

Conclusions:

• Subclinical sensory nerve involvement may be present in patients with monomelic amyotrophy, even in the absence of overt sensory symptoms or deficits.
• These findings challenge the traditional understanding of MA as a purely motor disorder and suggest a broader spectrum of involvement.