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Biomedical subjects

F Buchthal

Publications and source records attributed to F Buchthal.

At least 55 records · Page 3Linked to original sources

Sensory conduction from digit to palm and from palm to wrist in the carpal tunnel syndrome.

In normal subjects the maximum and minimum conduction velocity along sensory nerve was the same from digit to palm and from palm to wrist. Severe slowing from palm to wrist in patients with the carpal tunnel syndrome was often associated with only slight slowing from digit to palm. The distal slowing is attributed to a reversible constriction of nerve fibres, an assumption supported by the recovery in distal conduction velocity as early as two and a half months after decompression. The sensory velocity from wrist to elbow was normal or supernormal, whereas the motor velocity was often slightly decreased. The exclusion of the normal segment of the median nerve distal to the flexor retinaculum made it possible to demonstrate abnormalities across the flexor retinaculum in patients with clinical signs of carpal tunnel syndrome in whom distal motor latency and sensory conduction from digit to wrist were normal.

Adult↗

Normal sensory conduction in the nerves of the leg in man.

For comparison with findings in neuropathy, sensory conduction was studied along distal and proximal segments of the superficial peroneal, sural, and posterior tibial nerves in 71 healthy subjects 15 to 72 years of age and normal values were established (Table 2). In the distal segments of the nerves of the leg the amplitudes of the sensory potentials were one tenth those in the nerves of the upper extremity; the potentials were split up into several components, and electronic averaging was used routinely to analyse the shape of the potentials. The maximum sensory conduction velocity was 56·5 m/sec, SD 3·4 m/sec, in proximal; and 46·1 m/sec, SD 3·7 m/sec, in distal segments of the nerves (subjects 15 to 30 years, 34 to 36°C). Slowing of conduction with increasing age was the same proximally and distally (subjects 40 to 65 years: proximally 53·1 m/sec, SD 4·6 m/sec; distally 42·5 m/sec, SD 5·5 m/sec, 34 to 36°C). The velocity in the slowest components of the sensory potentials averaged 20 m/sec. The sensory velocity was 3 to 6 m/sec faster than the motor. The error arising from measuring the conduction distance on the surface across the capitulum fibulae was evaluated.

Action Potentials↗

Electrophysiological studies in diabetic neuropathy.

In 30 patients with diabetic neuropathy sensory potentials in the median nerve, motor conduction in the lateral popliteal and median nerves, and electromyographic findings in distal and proximal muscles were compared with the severity of symptoms and signs. All patients had abnormalities in at least one of the electrophysiological parameters. The sensory potentials were the most sensitive indicator of subclinical involvement; abnormalities were found in 24 patients, 12 of whom had no sensory symptoms or signs and five of whom had no other clinical or electrophysiological evidence of neuropathy in the upper extremities. This indicates that sensory nerve fibres may be affected before motor. The next most sensitive parameter was the presence of fibrillation potentials, found in more than half the distal muscles examined. Slowing in motor conduction in the lateral popliteal nerve was the only electrophysiological change correlated to the severity of the neuropathy, and no other electrophysiological parameter was correlated to the duration or the severity of the neuropathy or the diabetes. An onset of neuropathy before or simultaneously with the manifestations of the diabetes, as well as the frequent occurrence of asymptomatic changes in sensory conduction, support the evidence at hand that the neuropathy develops concomitantly with and as an integral part of the metabolic disturbance rather than as a consequence of the vascular complications of diabetes. Of three patients with clinical signs or symptoms of a diabetic amyotrophy, two had asymptomatic electrophysiological abnormalities in distal nerves and muscles, consistent with widespread involvement of the peripheral nerves. The third patient had electromyographic changes in the medial vastus muscles suggestive of a myopathy. Motor and sensory conduction in distal and proximal nerves were normal.

Adult↗