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Updated: Oct 19, 2026
Utility of Dissociated Intrinsic Hand Muscle Atrophy in the Diagnosis of Amyotrophic Lateral Sclerosis
Published on: March 4, 2014
Brachial amyotrophic diplegia: a slowly progressive motor neuron disorder
J S Katz1, G I Wolfe, P B Andersson
1Department of Neurology at Palo Alto VA Medical Center and Stanford University, CA 94304, USA.
Objective:
To describe a sporadic motor neuron disorder that remains largely restricted to the upper limbs over time.
Background:
Progressive amyotrophy that is isolated to the upper limbs in an adult often suggests ALS. The fact that weakness can remain largely confined to the arms for long periods of time in individuals presenting with this phenotype has not been emphasized.
Methods:
We reviewed the records of patients who had a neurogenic "man-in-the-barrel" phenotype documented by examination at least 18 months after onset. These patients had severe bilateral upper-extremity neurogenic atrophy that spared lower-extremity, respiratory, and bulbar musculature.
Results:
Nine of 10 patients meeting these criteria had a purely lower motor neuron disorder. During follow-up periods ranging from 3 to 11 years from onset, only three patients developed lower-extremity weakness, and none developed respiratory or bulbar dysfunction or lost the ability to ambulate.
Conclusion:
Patients presenting with severe weakness that is fully isolated to the upper limbs, without pyramidal signs, may have a relatively stable variant of motor neuron disease.
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