Biomedical subjects
Publications and source records attributed to C P Panayiotopoulos.
A case of self-induced pattern-sensitive epilepsy was observed in a 13-year-old girl. This case resembles those of patients who induce seizures in themselves by light stimulation. The close relationship between photosensitive and pattern-sensitive epilepsy is emphasized.
Two Greek female patients with Aicardi's syndrome are presented. The clinical picture, electroencephalogram, computer axial tomography scan, and the ophthalmological findings in these patients are described. The ocular features are emphasised because they can establish the diagnosis of this rare syndrome.
A 13-year-old girl had had two grand mal attacks induced by viewing television when she was aged 10 and 11 years, and again a year later. Clinical and electroencephalographic (EEG) findings were typical of photosensitive television epilepsy. However, a further grand mal seizure when the patient was age 13 years occurred in darkness. Two additional EEG studies showed continuous paroxysmal activity during darkness. The epileptiform discharges were abolished by light and eye opening.
Reports on clinical, electrophysiological and histological studies in dystrophia myotonica have shown that the peripheral nerves are usually not intact. In a few patients the neuropathy exceeds the myopathy. On the basis of these findings some authors believe that muscle changes in dystrophia myotonica are entirely due to the nerve lesions. However, despite the commonly found evidence of neuropathy, electromyographic and muscle biopsy findings are reported usually as "myopathic". Furthermore, clinical and laboratory findings indicate that the degree of muscle atrophy and peripheral nerve changes are unrelated. This report attempts to explain the discrepancies by suggesting that the "myopathic" and "neuropathic" changes in the muscle fibres in dystrophia myotonica are independent processes.
An electrophysiological method is described for estimating the conduction velocity in the proximal segments (anterior horn cells to the knee) of the motor fibres of the deep peroneal nerve. The method utilizes large numbers of F-waves which are late muscle responses due to antidromically activated motoneurones. The results in 58 healthy subjects are presented. A detailed literature review concerning the nature of F-wave is presented.
The F-wave has been used for estimations of motor nerve conduction velocity (MNCV) along the proximal segment (anterior horn cells to the knee) of the axons of the deep peroneal nerve in patients with renal failure and limb-girdle muscular dystrophy. MNCV and terminal latencies with conventional methods have also been estimated. Patients with chronic renal failure show marked F-chronodispersion (i.e. F-wave temporal dispersion) and impaired conduction along proximal and distal segments of the deep peroneal nerve. There is no evidence of motor nerve impairment, with conventional and F-wave methods, in patients with limb-girdle muscular dystrophy. It is shown that F-wave measurements are useful in electrophysiological studies of patients and may be more sensitive than conventional MNCV methods.
The development of the extensor digitorium brevis (EDB) muscle was studied in 39 healthy subjects, 27 patients with progressive proximal spinal muscular atrophy, 20 patients with limb-girdle muscular dystrophy and three with facioscapulohumeral muscular dystrophy. The EDB muscle is spared and usually hypertrophic in patients with muscular dystrophy, whereas it is often atrophic and weak in patients with spinal muscular atrophy. It is proposed that the degree of development of the EDB muscle can be used as a clinical sign in the differential diagnosis of progressive muscular atrophies.
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Electrophysiologic investigations were carried out in 15 patients with limb-girdle muscular dystrophy, two patients with Becker's muscular dystrophy, and 22 patients with dystrophia myotonica. The results were compared with those obtained in 18 patients who had chronic progressive motoneuron disease and in 39 control subjects. These results were within normal limits in muscular dystrophies, with the exception of dystrophia myotonica, in which a neural disturbance is evident in the majority of patients. The results in motoneuron diseases were as expected for neurogenic disorders, loss of motor axons and compensatory increase of the amplitude of muscle potentials. There is no evidence of motoneuron dysfunction in muscular dystrophies, but in dystrophia myotonica, the muscles and nerves are affected independently by the pleiotropic gene of the disease.
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The clinical, electrophysiological and muscle biopsy findings of 7 cases with a peculiar form of X-linked hereditary degenerative motor neuron disease are presented. It is suggested that the disease might be a separate clinical entity with the following characteristics: (1) sex-linked recessive inheritance, (2) unusual but not invariable late onset, (3) slow progression, (4) facial-bulbar and proximal spinal muscle involvement, (5) consistent fasciculations, sometimes massive and more pronounced about the lips, chin and tongue, (6) fine tremor of the hands, (7) muscle cramps usually preceding the other symptoms, and (8) gynaecomastia as a frequent but not a constant feature.
The F-wave has been used to estimate the motor nerve conduction velocity (MNCV) along the proximal segment (spinal cord to knee) of the axons of the deep peroneal nerve in patients with Charcot-Marie-Tooth disease and those with dystrophia myotonica. A new, modified method has been applied to estimate proximal MNCV in patients in whom F-waves or M-responses cannot be obtained from the small muscles of the foot. Terminal latencies and MNCV along the distal nerve segment (knee to ankle) have also been estimated using conventional techniques. The results have been compared with those obtained for control subjects. Proximal MNCV was severely slowed in every patient with Charcot-Marie-Tooth disease; the degrees of proximal and distal MNCV decreases were related. In patients with dystrophia myotonica, distal and proximal MNCVs were significantly reduced in comparison with control subjects, the MNCV slowing was not related to the degree of muscle atrophy. This is consistent with the hypothesis that the nerves and muscles are independently affected in dystrophia myotonica. It is concluded that the F-wave MNCV technique is as useful as, and may be more sensitive than, the conventional MNCV method.
The F-wave was used to estimate the fastest motor nerve conduction velocity (MNCV) along the proximal segment (spinal cord to knee) of the axons of the tibial nerve in 65 control subjects, 8 patients with diabetic polyneuropathy, and 4 patients with Charcot-Marie-Tooth disease. Terminal latencies and MNCV along the distal segment (knee to ankle) of the nerve were also estimated with the conventional M-response technique. This article describes another method for estimating sensory nerve conduction velocity (SNCV) along 1a fibers of the tibial nerve for the spinal cord-to-knee segment. Proximal and distal MNCV showed moderate slowing in patients with diabetic polyneuropathy and severe slowing in those with Charcot-Marie-Tooth disease. In 17 control subjects, proximal MNCV for the axons supplying the abductor hallucis muscle was compared to that estimated for the axons to the gastrocnemius muscle. MNCV for the proximal is faster than that for the distal small muscle. In 2 patients, M- and F-responses were not obtained from the abductor hallucis; in these patients, effective estimation of the proximal MNCV was made from the gastrocnemius muscle and showed marked reduction.
The F-wave was used to estimate motor nerve conduction velocity (MNCV) along the proximal segment of the fastest axons of the deep peroneal nerve (anterior-horn cells to knee) in 13 patients with amyotrophic lateral sclerosis (ALS) and in 21 age- and sex-matched control subjects. Measurements were based on the shortest latency of 100 F-waves obtained after supramaximal stimulation at the ankle and knee. The MNCV was estimated with the F-wave and conventional M-response methods in the distal segment (knee to ankle) of the nerve. Our results showed that proximal-nerve conduction is faster than distal conduction both in control subjects and in ALS patients. In ALS, there was a moderate reduction of MNCV, which was of equal degree in both the proximal and distal segments of the deep peroneal nerve. In control subjects and in ALS patients, no statistically significant difference was found between the MNCV estimated for the knee-to-ankle segment by conventional means and that obtained by the F-wave method. This indicates that the F-wave of shortest latency is conducted by the fastest surviving motor fibers, as in the initial components of the M-response--demonstrating that it is legitimate to make direct comparison of F- and M-latencies in estimating the proximal MNCV.
We have introduced the term F chronodispersion to denote the scatter or dispersion of the relative latencies of statistically significant numbers of consecutively recorded F waves. Five patients with chronic renal failure and five control subjects were studied. The two groups were matched for age, sex, proximal and distal motor conduction velocity, and latency of fast F waves plotted against distance traveled. We found that the extent of F chronodispersion of the deep peroneal nerve did not exceed 7.5 mscec in control subjects, while it was longer than this value in all uremic patients studied. Measurements of this type may prove to be a useful diagnostic tool for cases in which traditional electrophysiologic measurements are normal.
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