55 ?s ranged from 5 0%～100 0% (mean 60 6%) The ratio of block ranged from 0 0%～90 0% (mean 29 3%) FD ranged from 1 4～4 0 (mean 2 56) There were remarkably increased jitter, block and FD in 51 patients with definite or probable ALS It was also found that there was a negative correlation between extensor digitorum communis strength grades and the ncreased jitter with or without block and FD ( P

Objective To evaluate denervation changes [fibrillation potentials (fib) and positive sharp waves (psw)] in thoracic paraspinal muscles as diagnostic aids in amyotrophic lateral sclerosis (ALS). Methods The fib and psw of thoracic paraspinal muscles,the motor unit potential of sternocleidomastoid muscle were detected in 50 patients who had been identified as having ALS.Age and sex-matched,30 normal subjects and 30 patients who suffered radicular disease in cervical or lumbosacral region were also detected in thoracic paraspinal muscles for finding fib and psw serving as controls. Results In ALS group,a vast of fib and psw were found in thoracic paraspinal muscles in 41 of 50 ALS patients (82%),they were not found with sternocleidomastoid muscle,but the motor unit potential of this muscle was shown having long-duration and high-amplitude in 48 of 50 ALS patients (96%),which were coincided with the chronic neurogenic changes.6 of 50 patients had denervation changes of tongue muscles,3 of them found fib and psw.2 of 30 patients who suffered from radicular diseases were found with a few of fib and psw changes in thoracic paraspinal muscles.None of these symptoms were found in normal subjects.Conclusion A vast of fib and psw in thoracic paraspinal muscles should represent a sensitive tool for diagnosis of ALS.

Objective To analyze the clinical characteristics of dopa-responsive dystonia (DRD). Methods The clinical characteristics and the causes of misdiagnosis in 15 patients with DRD were reviewed retrospectively.Results 4 male and 11 female patients were investigated in this study. The age at DRD onset was from 3~25 years old,the average age was 11.7 years old.The courses ranged from 2 to 29 years and the average was 12.1 years. The symptoms in female patients often aggravated during gravidity and delivery. Main clinical features included gait irregularity, postural instability and tremor, with marked diurnal fluctuation. The disease may be misdiagnosed as cerebral palsy, idiopathic torsion dystonia, essential tremor, parkinson's disease, neurosis and so on. All the patients in this study improved obviously in 2 weeks after therapy with low dose of Madopar, and recovered in 2~4 years of follow up.Conclusions Clinical diversity and diurnal fluctuation are the characteristics of DRD. Early trial treatment with low dose of Levodopa should be highly recommended for the generalized dystonia in children and untypical adults.

Objective. To study the features and mechanism of the cerebral evoked potentials by repetitive stimulation of calf muscle in Duchenne muscular dystrophy (DMD) patients with obvious muscular dystrophy and psuedohypertrophy. Methods. Cerebral evoked potentials by stimulation of calf muscles and somatosensory evoked potentials (SEPs) by the stimulation of posterior tibial nerves at ankle were measured in 10 patients with DMD and 10 normal controls matched with gender and age. The intensity of the magnetic stimulation was at 30％ of maximal output (2.1 Tesla, MagPro magnetic stimulator, Dantec) and the frequency was 1 Hz. The low intensity of magnetic stimulation was just sufficient to produce a contraction of the muscle belly underneath the coil. Recording electrode was placed at 2 cm posterior to the Cz, reference to Fpz. The latencies of N33, P38, N48 and P55 and amplitude (P38－ N48) were recorded. SEPs were recorded by routine methods. Results. In normal subjects, the amplitudes of cerebral evoked potentials by magnetic stimulation of calf muscle was 40％ lower than that by electrical stimulation of the posterior tibial nerves at ankle. The latency of P38 was 2.9± 2.1 ms longer compared with electrical stimulation of the posterior tibial nerves at ankle. In 6 patients, P38 latency from magnetic stimulation was remarkably prolonged (P<0.01), and in 4 patients, there was no remarkable response. SEPs evoked by electrical stimulation were normal in all of the patients.? Conclusion. DMD is an available model for the study of mechanism of cerebral evoked potentials by magnetic stimulating muscle. We can conclude that the responses from magnetic stimulation were produced by muscle input. The abnormal responses in patients may relate to decreased input of muscle by stimulating dystrophic and psedohypertrophic muscle.

Objective To investigate preliminarily the value of phrenic nerve conduction (PNC) and diaphragmatic motor evoked potentials (MEPs) in the evaluation of various respiratory dysfunction (RDF).Methods Thirty-four patients with various RDF, (19 patients with neurogenical diseases and 15 patients with respiratory disorders) were investigated. Fifty healthy volunteers served as controls. The phrenic nerve was cutaneously stimulated by electrical pulse current at the midpoint of the posterior border of the sternomastoid muscle, and the diaphragmatic muscle compound action potentials (DCAP) were recorded between the 7th and 8th intercostal space and xiphoid process. When the magnetic transcranial stimulation (MTS) of the cortex was given, the recordings were made under the condition of maximal deep inspiration.Results All patients with myopathies had normal PNC. The patients with Guillain Barre syndrome (GBS), hereditary motor and sensory neuropathy (HMSN) and myasthenic crisis had abnormal PNC. The findings in PNC studies remarkably correlated with RDF, while serial examinations were performed in the patients with GBS and myasthenia gravis (MG). In 7 patients with sleep apnea syndrome (SAS), 4 had abnormal PNC, and 2 of 3 patients with chronic obstructive pulmonary diseases (COPD), and 1 of 5 patients with chest tightness or breathlessness on the supine position showed decreased amplitude. When MEPs were recorded, 3 of 5 patients showed abnormal SAS (1 had no response, 2 lower amplitude). Three patients with COPD had normal MEP.Conclusions PNC studies could not only evaluate neuromuscular RDF and predict the outcome of diseases, but also supply additional information about diaphragmatic dysfunction for the RDF caused by respiratory disorders. The results of PNC and diaphragmatic MEP may differentiate the types of SAS.