Search

To determine whether the naturally occurring amino acid threonine, a potential precursor for glycine biosynthesis in the spinal cord, has an effect on spasticity in multiple sclerosis, 26 ambulatory patients were entered into a randomized crossover trial. Threonine administered at a total daily dose of 7.5 g reduced signs of spasticity on clinical examination, although no symptomatic improvement could be detected by the examining physician or the patient. In contrast to the side effects of sedation and increased motor weakness associated with antispasticity drugs commonly used for the treatment of multiple sclerosis, no side effects or toxic effects of threonine were identified. Levels of threonine were elevated in serum and cerebrospinal fluid during treatment, but glycine levels did not change. Enhancement by threonine of glycinergic postsynaptic inhibition of the motor reflex arc in the spinal cord may represent a non-sedating, nontoxic approach to the management of spasticity in multiple sclerosis.

We performed electrodiagnostic tests on 113 consecutive patients with acute Guillain-Barré syndrome (103 within 3 weeks of onset). The most common motor conduction abnormalities were proximal conduction block alone (27%), proximal block associated with a distal lesion (27%), and generalized slowing (22%). Other combinations of abnormalities each occurred in fewer than 10% of patients. Thirty-seven percent of patients initially had normal sensory nerve conduction study results, most often in association with proximal conduction block. The characteristic early electrodiagnostic changes in Guillain-Barré syndrome were often present when cerebrospinal fluid protein concentration was still normal. Extensive early fibrillations occurred in 10 patients, 6 of whom recovered well. Patients with early generalized slowing of motor nerve conduction velocity, combined abnormalities, or low muscle action potential amplitudes in ulnar, median, and peroneal nerves generally, but not always, had poorer outcomes than patients with conduction block in one nerve segment. There was no consistent relationship between results of electrophysiologic studies and overall clinical grade or limb power, except that none of the patients with an isolated proximal block had virtual or complete paralysis in the same limb.

The diagnostic value of two simple tests of autonomic function, the RR interval variation and the sympathetic skin response, was evaluated relative to symptoms of dysautonomia in 53 patients with peripheral neuropathy. Of 22 patients with peripheral neuropathy and clinical dysautonomia, 15 showed abnormal results on both tests, and 7 had abnormal results on one test only. In none of the patients with dysautonomia were both tests' results normal. Conversely, all 15 patients with abnormal results of both sympathetic skin response and RR interval variation had symptoms of dysautonomia, while 7 of 15 patients with abnormalities limited to one test had such symptoms. No patient with normal results on both tests had clinical dysautonomia. These data indicate that RR interval variation and sympathetic skin response, both of which can easily be performed in the electromyography laboratory, are helpful in combination in the assessment of autonomic function in peripheral neuropathies.

The clinical features of pain were prospectively analyzed in 29 consecutive patients with Guillain-Barré syndrome (GBS). Sixteen (55%) had characteristic pain early in the illness described as similar to the muscular discomfort following exercise ("charley horse"). Pain preceded weakness by one to five days in four patients. The anterior and posterior aspects of the thighs, the buttocks, and the low part of the back were most frequently affected. Pain was frequently worse at night. Specific clinical signs or electrophysiologic abnormalities were not associated with pain, but serum creatine kinase level was elevated in ten of 13 patients with pain and only one of eight without pain. A review of previously reported pathologic material in five patients with GBS failed to disclose a relation between inflammation of dorsal root ganglia and pain. These results suggest that alterations in muscle related to neurogenic changes may cause the typical pain of GBS.

A patient with Fisher's variant of Guillain-Barré syndrome had severe limb ataxia. Joint position sense was diminished proximally but normal distally. In contrast, muscle proprioceptive function, studied electrophysiologically by recording silent periods in proximal muscles, appeared to be normal. A disparity between proprioceptive information from muscle spindles and kinesthetic information from joints and other proprioceptors may be a mechanism of ataxia, based solely on abnormalities of peripheral nerve function. A CNS lesion is, therefore, not necessary to explain cerebellar ataxia in Fisher's syndrome.

We describe a case of relapsing bilateral brachial plexopathy occurring during pregnancy and the postpartum period. This condition is known to occur with a familial predilection, but it has not been previously reported on a sporadic basis. The outcome was poor and associated with several psychosocial consequences.

Late response (H reflex and F response) and sural conduction studies were used in addition to conventional motor and sensory conduction to detect peripheral neuropathy in 30 randomly selected patients with chronic renal failure (18 receiving hemodialysis), five of whom had no clinical evidence of peripheral neuropathy; 30 age-matched control subjects were also studied. Conventional motor (median, ulnar, peroneal, and tibial) and sensory (median and ulnar) nerve conduction studies showed abnormalities of motor conduction in 25 (83%) and of sensory conduction in 26 (87%) patients. Abnormalities of sural nerve conduction and of late responses were present in all 30 patients. Five patients (17%) who had normal routine motor conduction showed abnormalities of late responses in the same nerve distribution. All electrophysiologic abnormalities were significantly more evident in lower limbs. Studies of late responses and sural conduction, in addition to improving the diagnostic yield, provide a method whereby effects of dialysis and medical management can be followed quantitatively in patients whose neuropathy would otherwise be undetectable.

A study of data on 30 patients with cervical spondylosis was carried out to determine whether short-latency somatosensory-evoked responses (SEPs) to median, ulnar, radial, and peroneal nerve stimulation provided additional information to that obtained by electromyography (EMG), late responses, and peripheral conduction studies. Peripheral studies, EMG results and SEPs were within normal limits in ten patients with pain, but without objective neurological deficit. By contrast, of ten patients who had objective signs of root compression, conventional EMG results were normal in nine, but abnormalities of the SEPs from radial nerve stimulation were obtained in only five patients, and were normal from ulnar and median nerve stimulation. In ten patients with clinical features of myelopathy, seven had abnormal median SEPs and all had abnormal peroneal SEPs, whereas EMG results were abnormal in only five patients. It is suggested that SEPs and EMG are both of limited use in patients with only symptoms of root compression. In patients with signs of root compression, EMG is the most sensitive procedure; however, some additional information can be obtained from superficial radial SEPs. In patients with cervical myelopathy, SEP was the most useful procedure, especially when upper and lower limbs were studied.