Repeated single fiber recordings do not affect the jitter and the fiber density.

The temporal variation of at least two muscle fibers of the same motor unit was recorded with the single fiber EMG technique (SFEMG) by means of special needles and filter settings. In the normal musculus extensor digitorum communis (EDC) the mean variation (jitter) is not longer than 37 microseconds, the fiber density not higher than 1.7 fibers in a 10 ms window. To determine whether these parameters are affected by repeated SFEMG recordings, we measured jitter and fiber density in 20 fiber pairs in the left extensor digitorum communis muscle on day 0, 3, 6, 9 and 30 in 5 healthy volunteers. The mean jitter and the fiber density did not change significantly from day 0 (30.1 +/- 3.6 microseconds; 1.4 +/- 0.07) to day 30 (34.5 +/- 2.7 microseconds; 1.6 +/- 0.13). We conclude that repeated SFEMG recordings do not influence jitter and fiber density.

Time course of distant effects of local injections of botulinum toxin.

Botulinum toxin A (btx) is used to treat focal dystonias. From accidental intoxications it is known that btx can cause generalized pathologic single-fiber electromyography (SFEMG) findings. We monitored the onset and course of these disturbances in eight patients who received a small dose of btx (2-22 ng) for therapy of focal dystonias in the head/neck region for the first time via repeated SFEMG investigations at days 0, 3, 6, 9, 12, 28, and 56. Recordings were performed in the extensor digitorum brevis muscle, and in two patients additionally in the tibialis anterior muscle. In six of these patients we found an increase of jitter and blocking. The onset of these changes was in the range of 3-13 days after injection. Fiber density showed a tendency to increase. There was no correlation between SFEMG findings and the dose of injected btx. Possible mechanisms for these observations may be either a very efficient local uptake and retrograde axonal transport via the spinal motor neurons or a systemic distribution via the blood circulation.

Complete bilateral internal ophthalmoplegia as sole clinical sign of botulism: confirmation of diagnosis by single fibre electromyography.

A case of complete bilateral internal ophthalmoplegia as the sole clinical sign of botulism is reported. Diagnosis was immediately confirmed by single-fibre electromyography (SFEMG), which revealed abnormally high blocking (14.3%), contrasting with moderately increased jitter (mean consecutive difference in the extensor digitorum communis muscle, 43.9 microseconds). After giving equine botulinum antitoxin and simultaneous forced emptying of the bowels, ocular symptoms completely disappeared within 2 days. Six days, 5 weeks and 6 months after the first SFEMG study, the jitter was still abnormal, even becoming more so with time. Blocking, however, was only rarely observed in the follow-up studies. It is concluded that SFEMG may serve as a useful and sensitive method for the rapid diagnosis of botulinum intoxication, even in cases where no clinical signs of general muscular weakness are apparent.

Non-invasive topographic analysis of intestinal activity in man on the basis of acustic phenomena.

In an attempt to find a non-invasive method yielding a comprehensive insight into a patient's intestinal activity, continuous multichannel registration and analysis of acustic phenomena as produced by the intestines were performed. Previous work, described by others, was further developed with respect to topographical interpretation of the data obtained, and to the possible introduction into general clinical use by installing different methods of artifact detection and reduction. To record and process bowel sounds, a device developed for this purpose (Phonoenteroanalyzer PEA-06, G-W Elektronik, Munich, FRG) was used. Five specially designed microphones were placed on the abdominal wall. After amplification and filtering, further processing of the signal was achieved by means of rectifying, peak detection, and logarithmic transformation techniques, yielding a topographically discernible pattern of intestinal activity. Noise and movement artifacts, although a basic problem of this technique, could be adequately managed, e.g., by using a control microphone as well as simultaneous registration of breathing. Ten normal subjects as well as eight patients with manifest or suspected gastrointestinal problems, had their bowel sounds registered either continuously overnight or during adequate stimulatory tests (gastrocolonic response, neostigmine test, rectal distension). Bowel sounds were registrated as short "clicks" or longer lasting, sometimes rhythmically appearing, complex acustic phenomena. Overnight registrations revealed periodical changes in general or local intestinal activity, which in turn showed remarkable interindividual variabilities. Stimulatory tests provoked an enhancement of intestinal activity, which could well be documented with this method. In conclusion, analysis of acustic phenomena provoked by the bowels should henceforth allow an objective, continuous, long-term, non-invasive, indirect, and at any time repeatable topographical registration of intestinal activity.

[Central motor conduction time in multiple sclerosis: an comparison of visual and somatosensory evoked potentials in relation to the type of disease course]. / Zentrale motorische Leitungszeit bei Multipler Sklerose: ein Vergleich mit visuell und somatosensorisch evozierten Potentialen in Abhängigkeit von Verlaufstyp.

The central motor conduction time (CMCT) was measured by electrical transcranial and spinal stimulation in 70 consecutively admitted patients with definite multiple sclerosis and 26 normal volunteers. The results of the patientgroup were compared with visual and somatosensory (median and tibial nerve) evoked potentials. The mean CMCT of the volunteers was 5.4 ms versus 11.1 ms in the patient group. In 55 of the 70 patients (79%) the CMCT was delayed (p less than 0.0001). VEP showed pathologic results in 67%, SEP of tibial nerve in 51%, SEP of median nerve in 41% of the patients. In 10 of the 70 cases (15%) only CMCT was pathologic. Especially in the first attack of the disease the CMCT (79% pathologic results) was superior in comparison to the evoked potentials (VEP and SEP together 43% pathologic findings). In our cases without clinical evidence of a pyramidal tract lesion a subclinical affection of this pathway could be determined in 69% by a pathologic CMCT. We regard this method therefore as a valuable tool in the early diagnosis of multiple sclerosis.

Autosomal dominant Emery-Dreifuss syndrome: evidence of a neurogenic variant of the disease.

The first German family with autosomal dominant Emery-Dreifuss syndrome (EDS) is described, with electrophysiologic and myopathologic results providing evidence of a primary neurogenic disease. According to classification of the scapulo peroneal syndrome without cardiomyopathy, we conclude that there are two variants of EDS: one myopathic, the other neurogenic in origin. Therefore, the term Emery-Dreifuss muscular dystrophy should be avoided. Instead, each case of EDS should be classified as myopathic or neurogenic with X chromosome recessive or autosomal dominant inheritance.