Biomedical subjects

A J Sumner

Publications and source records attributed to A J Sumner.

57 records · Page 4Linked to original sources

PubMed1970

Wasting of the hand associated with a cervical rib or band.

Nine patients are described with unilateral wasting of the hand muscles associated with elongated C7 transverse processes or with rudimentary cervical ribs. In three patients there was selective wasting of the lateral part of the thenar pad, accompanied by mild weakness of the other hand muscles. In four patients all the hand muscles were wasted, but this was more marked in the lateral part of the thenar pad than elsewhere. In two patients wasting was uniformly distributed throughout the hand. Weakness and wasting in the forearm was only present in four patients and was relatively mild. Sensory loss, when present, affected mainly the inner side of the forearm. Nerve conduction studies revealed no abnormality in the distal part of the median nerve, but some patients had reduced or absent sensory action potentials when the fifth finger was stimulated. In all nine patients a sharp fibrous band was found at operation, which extended from an elongated C7 transverse process or from a rudimentary cervical rib to the region of the scalene tubercle on the first rib. The fibrous band caused angulation of the C8 and T1 roots in five patients, and of the lower trunk of the brachial plexus in three. Pathological changes were frequently visible in affected nerves at the site of angulation. Division of the fibrous band relieved pain and paraesthesiae in eight patients and arrested muscle wasting and weakness in nine patients. There was, however, only slight recovery of power in affected muscles; wasting in the hand appeared to be unchanged after periods of up to eight years.

Action Potentials↗

PubMedDate not supplied

Clinical electrophysiology of infantile botulism.

Infantile botulism is a recently recognized cause of acute hypotonic paresis and respiratory failure in young infants. Electrophysiological testing has proven useful in early diagnosis in suspected cases by demonstrating abnormal neuromuscular transmission as is known to occur in botulism. Twenty-five infants with bacteriologically proven botulism were studied by uniform methods in our laboratory and characteristic electrophysiological abnormalities were found. Repetitive stimulation at 20 and 50 Hz was the most specific single test; 23 patients (92%) showed incremental responses. Stimulation at low rates was less specific. Concentric needle electromyography provided useful supplemental information. Short-duration, low-amplitude motor unit potentials were prominent in 22 patients (92%) accompanied by abnormal spontaneous activity in 13 patients (54%). Compound muscle action potential amplitudes were usually reduced, but motor and sensory conduction studies were otherwise normal. Electrodiagnostic testing demonstrated one or more characteristic abnormalities in all cases of infantile botulism. This constellation of electrophysiological abnormalities, combined with an appropriate clinical picture, was so distinctive as to allow early presumptive diagnosis of infant botulism, before the results of bacteriological testing were available.

Action Potentials↗

PubMedDate not supplied

Acquired versus familial demyelinative neuropathies in children.

The electrophysiologic differences between chronic acquired demyelinative neuropathy and the demyelinative form of Charcot-Marie-Tooth disease have recently been reported. The present report extends these observations to include the genetically determined demyelinating neuropathies seen in metachromatic leukodystrophy, Krabbe's leukodystrophy, and Cockayne's syndrome. The electrophysiologic features of metachromatic leukodystrophy (five patients), Krabbe's (four patients), and Cockayne's syndrome (three patients) were all similar. There was uniform slowing of conduction (both in different nerves and in different nerve segments), and conduction block was not seen. These findings are consistent with a uniform degree of demyelination in multiple nerves and throughout the entire length of individual axons. Thus, uniform slowing of nerve conduction constitutes strong evidence for a familial demyelinative neuropathy, as opposed to the multifocal slowing seen in acute and chronic acquired demyelinative neuropathy.

Adolescent↗