桑原 聡

The authors reviewed the clinical features and outcome of Miller Fisher syndrome (MFS) for 50 consecutive patients with MFS including 28 patients who received no immunotherapy. Besides the characteristic clinical triad (ophthalmoplegia, ataxia, and areflexia), pupillary abnormalities! blepharoptosis, and facial palsy are frequent in MFS, whereas sensory loss is unusual despite the presence of profound ataxia. Patients with MFS usually had good recovery and no residual deficits.

Objectives-To investigate whether accommodation to depolarising and hyperpolarising currents differs for motor axons of human upper and lower limb nerves. Methods-The threshold tracking technique was used to measure threshold electrotonus for median and peroneal motor axons. The threshold current that produced a compound muscle action potential 50% of maximum was measured, and membrane potential was altered using subthreshold polarising currents of 330 ms duration but of variable intensity, from +40% (depolarising) to -100% (hyperpolarising) of the unconditioned threshold. Results-The maximal threshold changes (the peak of the S1 phase of threshold electrotonus) were significantly greater in median axons for both depolarising and hyperpolarising currents. The subsequent phases of accommodation to depolarising currents (S2) and to hyperpolarising currents (S3) were also significantly greater in median axons. These findings raised the possibility that greater accommodation (S2 and S3) in median axons resulted from greater changes in membrane potential. However, regression of S2 against S1 to depolarising currents disclosed significantly greater accommodation (27.8%) for median axons, suggesting that slow K+ conductances may be more prominent on median than peroneal axons. By contrast, the relation between S3 and S1 to hyperpolarising currents was similar for the two nerves, suggesting that the difference in inward rectification was merely because the conductance varies with the extent of hyperpolarisation. Conclusions-Slow K+ conductances are more prominent for median motor axons than for peroneal axons. It would therefore be expected that axons innervating the lower limbs have less protection from depolarising stress and could develop ectopic activity more readily.

Background Activated macrophages and T lymphocytes may play a role in the pathogenesis of chronic inflammatory demyelinating polyneuropathy (CIDP). Both cell types secrete tumor necrosis factor-alpha (TNF alpha), which has toxic effects on myelin and endothelial cells. Methods: The serum concentration of TNF alpha was measured by ELISA and compared with clinical and electrophysiological profiles in 20 patients with CIDP. Results: An increased serum level of TNF alpha was detected in 5 (25%) patients and was associated with subacute progression, severe neurologic disabilities, and symmetric weakness involving proximal as well as distal muscles. TNF alpha levels increased during the active phase in this subgroup of patients. The levels of TNF alpha correlated with the severity of demyelinating conduction abnormalities in the intermediate as well as distal nerve segments, suggesting demyelination diffusely distributed along the nerves. Conclusion: Circulating TNF alpha increases during the active phase in a subgroup of CIDP patients and may play a role in the pathogenesis of demyelination and the breakdown of the blood-nerve barrier in CIDP.

1. Voluntary contraction of a muscle causes substantial hyperpolarization of the active motor axons due to activation of the electrogenic Na+-K+ pump. The present study was undertaken to determine whether voluntary effort produces a significant impairment in impulse transmission in normal axone and whether mechanisms other than membrane hyperpolarization contribute to the changes in axonal excitability. 2. The compound muscle action potential (CMAP) was recorded after median nerve stimulation at the wrist using sub- and supramaximal stimuli, delivered singly and in pairs at conditioning-test intervals of 2-15 ms. Axonal excitability parameters (threshold, refractoriness, supernormality, and strength-duration time constant (tau (SD))) were measured using threshold tracking. Impulse transmission was assessed using supramaximal stimuli. 3. Maximal voluntary contractions of the abductor pollicis brevis for 1 min produced a substantial increase in threshold, an increase in supernormality and a decrease in tau (SD), all of which lasted similar to 10 min and indicate axonal hyperpolarization. However, immediately after the contraction there was an unexpected increase in refractoriness. The post-contraction increase in refractoriness could mot be mimicked by an imposed ramp of hyperpolarization that produced changes in the other indices to an extent that was similar to voluntary contraction. 4. The contraction had relatively little effect on the size of the unconditioned maximal CMAP. However, there was failure of transmission of supramaximal conditioned volleys when the conditioning-test interval was short. 5. The relationships between axonal excitability and supernormality and tau (SD) following voluntary contraction differed significantly from those recorded during the hyperpolarization produced by DC current. It is argued that these differences probably result from extra-axonal K+ accumulation with the voluntary contraction but not with the DC polarization. 6. It is concluded that, following maximal voluntary contraction of a normal muscle, the refractory period of transmission is impaired distal to the stimulus site sufficient to cause transmission failure of the second of a pair of closely spaced impulses. The site of transmission failure is: likely to be the terminal axon, presumably at branch points, possibly in the unmyelinated pre-terminal segment.

Motor unit number estimate (MUNE) of the abductor pollicis brevis (APB) was sequentially performed in seven patients with acute motor axonal neuropathy (AMAN). The MUNE markedly decreased (mean, 11)at the peak of the illness. Clinical recovery of APE strength began during week 4, with an increase in amplitude of distal compound muscle action potentials. The MUNE did not change significantly in this early recovery phase and increased slowly with time. The main mechanism for early recovery in AMAN may be collateral reinnervation, with nerve regeneration developing later. (C) 2001 John Wiley & Sons. Inc.

1. To determine whether accommodation to depolarizing and hyperpolarizing stimuli differs for cutaneous afferents in the median and sural nerves, studies were performed in normal human subjects using threshold electrotonus. 2. The changes in threshold for compound sensory action potentials of 50 % of maximum were recorded when the nerves were subjected to long-lasting depolarizing and hyperpolarizing DC. The premise was that the threshold changes largely mirror the underlying electrotonic changes in membrane potential. 3. The maximal threshold changes produced hyperpolarizing and hyperpolarizing currents were greater for median afferents, suggesting that the DC produced greater changes in membrane potential in these afferents. 4. Median afferents underwent greater accommodation to depolarizing currents than sural afferents and a greater threshold undershoot at the end of the currents, suggesting greater activity of a slow K+ conductance. Median afferents also underwent greater accommodation to hyperpolarizing currents, suggesting greater inward rectification. 5. These conductances are voltage dependent, and the differences in accommodation could be due to greater changes in membrane potential for the median nerve. The changes in threshold produced by long-lasting depolarizing and hyperpolarizing currents of graded intensity were therefore measured. When the threshold changes were matched for the two nerves, median afferents underwent 22.4% more accommodation to depolarizing currents and 28.7% more accommodation to hyperpolarizing currents. 6. We conclude that there is greater expression of two internodally located conductances responsible for accommodation on median afferents. The biophysical differences identified in this study might contribute to the finding that sural afferents hare a greater tendency to dysfunction than median afferents.

Voluntary activity produces activity-dependent hyperpolarization of the active motor axons. The present study investigated whether this hyperpolarization produces conduction block in chronic inflammatory demyelinating polyneuropathy (CIDP). Studies were performed in 10 healthy control subjects, 7 patients with CIDP, and 3 patients with multifocal motor neuropathy. The compound muscle action potential (CMAP) of the abductor pollicis brevis was recorded in response to supramaximal stimuli to the median nerve at the wrist, alternating with measurements of axonal excitability. After a maximal voluntary contraction for 60 seconds, the amplitude of the maximal CMAP was significantly reduced in symptomatic CIDP patients by 40%, but there were only slight changes in the CMAPs of healthy controls, asymptomatic CIDP patients, and multifocal motor neuropathy patients. In symptomatic CIDP patients, the activity-dependent conduction block paralleled the activity-dependent hyperpolarization and was presumably precipitated by it. In these patients, the safety margin for impulse conduction was estimated to be about 12%, Activity-dependent conduction block may be clinically important in chronic demyelinating diseases and can be demonstrated electrophysiologically if testing occurs across pathological sites.

In a number of clinical studies, measurement of axonal strength-duration properties has been used to provide indirect insight into conductances at the node of Ranvier, particularly persistent Na+ conductance. However, the specificity of any changes is limited because other factors can affect strength-duration behavior. The present study was undertaken to define the relationship between different strength-duration measures at rest and at different membrane potentials, and also to determine the limits within which strength-duration behavior can be used as a measure of nodal conductances. The strength-duration time constant (tau (SD)) and rheobase of 20 single motor units in the flexor carpi ulnaris were calculated from thresholds defined using threshold tracking.'True" rheobase and rheobasic latencies were measured using test stimuli of 100 -ms duration. For ten units, the technique of latent addition was used to measure threshold changes directly attributable to nodal conductances, and for six units these were compared with strength-duration properties at different membrane potentials. The data indicate that measurements of tau (SD) and rheobase can provide sensitive indicators of conductances present at the node of Ranvier when membrane potential changes. There is a reciprocal relationship between tau (SD) and rheobase for single motor units at different membrane potentials, and this relationship may allow changes in tau (SD) due to depolarization and demyelination to be differentiated. (C) 2000 John Wiley & Sons, Inc.

Threshold tracking was used to compare excitability properties (stimulus-response curves, strength-duration properties, recovery cycle, and threshold electrotonus) of median motor axons at the wrist and peroneal motor axons at the ankle in 12 healthy subjects. Stimulus-response curves and strength-duration properties were similar, though higher stimulus intensities were required for peroneal axons. However, there were significant differences in the recovery cycle of excitability following a conditioning stimulus and in threshold electrotonus. In the recovery cycle, median axons had significantly greater supernormality and late subnormality. In threshold electrotonus, the initial slow threshold changes in response to subthreshold depolarizing and hyperpolarizing currents (S1) were significantly greater in median axons, and there was also greater accommodation to depolarizing currents (S2) and greater threshold undershoot after depolarization. Similar differences in supernormality and the S1 phase of threshold electrotonus were found between peroneal axons at ankle and knee, suggesting that these properties may be dependent on nerve length. When median motor axons at the wrist were compared with peroneal motor axons at the knee, there were no differences in refractoriness and supernormality and only small differences in S1, but the late subnormality and undershoot were significantly greater in the median axons. These findings suggest that, in addition to any length-dependent differences, peroneal axons have a less prominent slow K+ conductance. We conclude that the properties of different motor axons are not identical and their responses to injury or disease may therefore differ. (C) 2000 John Wiley & Sons, Inc.

Objective: To investigate responsiveness of human cutaneous mechanoreceptor to selective tactile stimuli produced by brief air-puff stimulation. Methods: Using percutaneous microneurography, activities of single sensory units innervating glabrous skin of the hand were recorded, and air-puff stimuli with a short rise time (0.5 Ins), generated by a high-speed ail control system, were applied to the receptive field. Receptor activation time was estimated as the latency difference between electrically and air-puff evoked responses. Results: Thirty units were analyzed: all 4 kinds of mechanoreceptors of human glabrous skin (fast adapting type 1 [FA I, II = 7], fast adapting type [FA II, ii = 4], slowly adapting 1 [SA I, II = 5] and slowly adapting 2 [SA II, ii = 14]) were activated by air-puff stimulation. Estimated receptor activation times were 0.6-6.2 ms (mean 2.2 ms). FA II units occasionally responded twice or more to a single air-puff stimulus. Conclusions: Brief air-puffs can activate all 4 human cutaneous mechanoreceptors. and the receptor transduction time is estimated as approximately 2.0 ms. Properties of human mechanoreceptors can be studied using air-puff stimulation and microneurography. (C) 2000 Elsevier Science ireland Ltd. All rights reserved.

To investigate the sensory nerve responses to selective touch stimulation, sensory nerve action potentials after brief air-puffs were recorded with a microelectrode. In patients with peripheral neuropathy, those with impairment of tactile sensations had significantly smaller responses than did those without tactile impairment, suggesting receptor activation failure as well as nerve conduction failure. Brief air-puff stimulation, when combined with microneurography, could be used for evaluating the tactile receptor properties in humans.

We describe a patient who developed Guillain-Barré syndrome (GBS) following hand-foot-and-mouth disease (HFMD) which is known to be caused by enterovirus infection. A 35-year-old man developed acute paraparesis and dysesthesia in the four limbs following typical skin eruption of HFMD. Electrophysiologic studies showed peripheral nerve demyelination predominant in the distal terminals. HFMD is a rare cause of meningitis, encephalitis, and polio-like myelitis, but GBS following HFMD has never been described.

IgG anti-GQ1b antibody was present in a patient with acute ataxia and areflexia without ophthalmoplegia or elementary sensory loss. Sensory nerve conduction studies and somatosensory evoked potentials were normal, but postural body sway analysis showed dysfunction of the proprioceptive afferent system. The clinical presentation and laboratory results for this patient resemble those of Miller Fisher syndrome, except for the lack of ophthalmoplegia. This case may represent part of an IgG anti-GQ1b syndrome.

Griffin and colleagues (Griffin JW, Li CY, Ho TW, Tian M, Gao CY, Xue P, Mishu B, Cornblath DR, Macko C, McKhann GM, Asbury AK, Pathology of motor-sensory axonal Guillain-Barre syndrome. Ann Neurol 1996;39:17-28 [4]) proposed that acute motor axonal neuropathy (AMAN) and acute motor-sensory axonal neuropathy (AMSAN) are part of the spectrum of a single type of immune attack on the axon. In contrast, IgG anti-GM1 antibody is associated closely with AMAN, but whether other IgG anti-ganglioside antibodies are associated with this neuropathy is not clear. We investigated whether IgG anti-ganglioside antibodies can be used as immunological markers to differentiate AMAN from acute inflammatory demyelinating polyneuropathy (AIDP) and whether these autoantibodies are present in AMSAN. The frequencies of anti-GM1, anti-GM1b, and anti-GD1a IgG antibodies in 21 AMAN patients were significantly higher than in 19 AIDP patients. Anti-GM1b and anti-GD1a IgG, as well as anti-GM1 IgG antibodies, therefore are immunological markers for AMAN. The patients with AMSAN had anti-GM1, anti-GM1b, and anti-GD1a IgG antibodies, indicative that AMAN and AMSAN share a common immunological profile. (C) 1999 Elsevier Science B.V. All rights reserved.

Objectives-To investigate the incidence of hyperreflexia in patients with Guillain-Barre syndrome (GBS), and its relation with electrodiagnosis of acute motor axonal neuropathy (AMAN), antiganglioside GM1 antibody, and Campylobacter jejuni infection. It was reported that patients with AMAN in northern China often had hyperreflexia in the recovery phase. Methods-In 54 consecutive Japanese patients with GBS, sequential findings of tendon reflexes were reviewed. Ey electrodiagnostic criteria, patients were classified as having AMAN or acute inflammatory demyelinating polyneuropathy (AIDP). Anti-GM1 and anti-C jejuni antibodies were measured by enzyme linked immunosorbent assays. Results-Seven (13%) patients developed hyperreflexia with the spread of the myotatic reflex to other segments in the early recovery phase, one of whom already had hyperreflexia in the acute progressive phase. Of the seven patients, six had AMAN and all seven had anti-GM1 antibodies, whereas only two had anti-C jejuni antibodies. Hyperreflexia was more often found in patients with AMAN than AIDP (6/23 v 1/18, p = 0.002), and in patients with anti-GM1 antibodies than without them (7/26 v 0/28, p = 0.01). Hyperreflexic patients had milder peak disabilities than patients without hyperreflexia (p = 0.03). Increased motor neuron excitability in the hyperreflexic patients was supported by increased soleus H-reflex amplitudes and the appearance of II-reflexes in the small hand or foot muscles. Conclusions-Hyperreflexia often occurs in patients with GBS especially with AMAN, anti-GM1. antibodies, and milder disease. Increased motor neuron excitability further characterises the subgroup of patients with GBS with AMAN and anti-GM1 antibodies.

In some patients with amyotrophic lateral sclerosis (ALS), the thenar hand is more severely affected than the hypothenar hand. To quantify the dissociated involvement, we examined the motor unit number estimate (MUNE) of both the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles in 23 patients with ALS. Whereas ALS patients had significantly smaller MUNEs than normal subjects in both muscles, the extent of motor unit loss was significantly greater in the APE than ADM. Moreover, a simple comparison of the amplitude of compound muscle action potentials (CMAPs) showed that ALS patients had significantly smaller APB/ADM ratios than normal subjects and patients with cervical spondylotic amyotrophy, bulbospinal muscular atrophy, or peripheral neuropathy, The more severe involvement of the APE probably reflects the specific pathophysiology in ALS, and possible mechanisms for the dissociated involvement are discussed. (C) 1999 John Wiley & Sons, Inc.

If anti-GM1 antibody plays a role in the axonal damage in Guillain-Barre syndrome, the common entrapment sites may be preferentially involved with evidence of axonal dysfunction. To assess this hypothesis, we studied nerve conduction across the cubital tunnel in 44 patients. Abnormal amplitude reduction of compound muscle action potentials (CMAPs) was found in 45% of 20 immunoglobulin G (IgG) anti-GM1-positive and in 29% of 24 anti-GM1-negative patients. The time course and sequel were distinct between the two groups. In the former group, the amplitude reduction was prominent in weeks 1 to 2 and was followed by a decrease in distal CMAPs (axonal degeneration) or an increase in proximal CMAPs (resolution of conduction block), In contrast, anti-GM1-negative patients showed slower resolution with temporal dispersion. In anti-GM1-positive cases, amplitude reduction at the common entrapment site is frequent and may reflect wallerian degeneration or physiological conduction block at the nodes of Ranvier, both suggesting axonal involvement. (C) 1999 John Wiley & Sons, Inc.

The purpose of this study was to investigate activity-dependent excitability changes in polyneuropathy and their correlation with symptomatology. First, we recorded sensory nerve action potentials (SNAPs) with an intraneural microelectrode during impulse trains in 11 patients with chronic inflammatory demyelinating polyneuropathy, When the stimulus frequency was increased to greater than or equal to 20 Hz, all patients showed marked decreases in the amplitudes of averaged SNAPs (128 responses) associated with latency increases. The amplitude decreases were much greater than those in patients with axonal neuropathies. In single-unit recordings, responses showed latency increases, which were small but sufficient to cause decreases in the averaged responses. Clinical sensory impairment was correlated with the degree of preexisting conduction block or axonal loss, but not with the degree of rate-dependent amplitude decreases. Activity-dependent changes occur preferentially in demyelinating neuropathy and are a sensitive measure of demyelination. The mechanism responsible for the amplitude decreases could be conduction slowing or block caused by activity-dependent hyperpolarization. (C) 1999 John Wiley & Sons, Inc.

Object: To study the effects of the intravenous administration of methylcobalamin, an analogue of vitamin B-12, for uremic or uremic-diabetic polyneuropathy in patients who are receiving maintenance hemodialysis. An ultra-high dose of vitamin B-12 has been reported to promote peripheral nerve regeneration in experimental neuropathy, Methods: Nine patients received a 500 mu g methylcobalamin injection 3 times a week for 6 months. The effects were evaluated using neuropathic pain grading and a nerve conduction study. Results: Serum concentrations of vitamin B-12 were ultra-high during treatment due to the lack of urinary excretion. After 6 months of treatment, the patients' pain or paresthesia had lessened, and the ulnar motor and median sensory nerve conduction velocities showed significant improvement. There were no side effects. Conclusion: Intravenous methycobalamin treatment is a safe and potentially beneficial therapy for neuropathy in chronic hemodialysis patients.

To examine the validity of electrodiagnostic tests to help diagnosis and to evaluate disease activity of juvenile atrophy of unilateral upper limb (Hirayama's disease), we reviewed the results of nerve conduction studies, motor unit number estimates, electromyography, and somatosensory evoked potentials in consecutive 38 patients. There was selective involvement of the C8-T1 myotomes, in which motor unit loss was more prominent in the abductor digiti minimi than in the abductor pollicis brevis muscles, and F wave persistency was decreased out of proportion to the motor unit loss. These findings may help diagnosis. With respect to the disease activity and treatment, denervation potentials in the flexor carpi radialis muscle were more frequent in patients with shorter disease duration than those with longer duration. Median F wave persistency was greater in patients treated with neck brace than in patients without the treatment. These parameters can monitor the disease activity and efficacy of treatment.

To investigate whether ataxia in Miller Fisher syndrome (MFS) is caused by loss of proprioception or cerebellar dysfunction, we studied the power spectrum peak of the body sway frequency in 10 MFS patients, and compared the results with those of patients with cerebellar or sensory ataxia. The cerebellar patients had a peak at 2.4 Hz, whereas sensory ataxia patients had a 1-Hz peak. Nine of the MFS patients had a distinct 1-Hz peak. Clinical sensory loss or abnormal sensory nerve potentials were present in only 3 patients, whereas soleus H-reflexes were absent in all the MFS patients. MFS patients have dysfunction of the proprioceptive afferent system, and the special sensory ataxia may be caused by the selective involvement of muscle spindle afferents.

To assess the clinical and electrophysiological features of n-hexane neuropathy caused by addictive inhalation, 4 patients were studied in the progressive phase. The neurological manifestations were characterized by subacute predominantly motor polyneuropathy and disease progression despite discontinuance of the chemicals, which were similar to those reported in industrial exposure, although with a severer degree associated with anorexia and body weight loss. Electrophysiological studies showed that all showed multifocal conduction block and profound conduction slowing, as well as features of axonal degeneration, Sural nerve biopsy showed axonal loss, axonal swelling, and thin myelin probably due to retraction by axonal swelling. n-Hexane abuse causes severe subacute polyneuropathy. The mixed axonal and demyelinating electrophysiological features were consistent with peculiar pathological findings. Conduction block, probably due to paranodal myelin retraction or ongoing wallerian degeneration, is very frequent and could be responsible for the clinical deficits, especially in the early phase of illness.

Objective: To investigate the prognostic value of anti-GM1 antibody. Background: Whether anti-GM1 antibody is a marker of poor prognosis due to axonal degeneration in Guillain-Barre syndrome (GBS) is a matter of controversy. Methods: The clinical recovery of 41 consecutive GBS patients was analyzed. Results: The Hughes functional grading scores were similar at the peak, and 1, 3, and 6 months after onset for the groups of patients with (n = 19) and without (n = 22) immunoglobulin (Ig) G anti-GM1 antibodies. However, the anti-GM1-positive group included significantly higher proportions of patients with poor recovery (inability to walk independently at 6 months, 5 of 19 versus 0 of 22; p = 0.01) and those with a markedly rapid recovery (improvement by two or more Hughes grades within a month, 9 of 19 versus 4 of 22; p = 0.05). The positivity of IgG anti-GM1 antibody correlated well with the electrodiagnosis of the acute motor axonal neuropathy pattern but was not always associated with poor prognosis. Anti-GM1-positive patients showed two different patterns of clinical recovery-their conditions improved slower or faster than those of the anti-GM1-negative patients, most of whom had acute inflammatory demyelinating polyneuropathy. Conclusions: Anti-GM1 antibody is not always a marker of poor prognosis and, besides axonal degeneration, early reversible effects other than demyelination could be part of the pathophysiology of Guillain-Barre syndrome with IgG anti-GM1 antibody.

Beneficial treatment has not been established for chronic sensory ataxic neuropathy associated with Sjogren's syndrome (CSAN-SS). We describe two patients with CSAN-SS who clinically improved in response to D-penicillamine treatment. Their neuropathic symptoms were lessened after D-penicillamine, and the results of electrophysiologic studies support the clinical improvement. D-Penicillamine can be considered a potentially beneficial agent in the treatment of CSAN-SS.

Thirty-one cases (26 patients) of clinically definite multiple sclerosis with predominant spinal cord involvement were studied retrospectively, focusing in particular on the results of sensory testings which were compared with the findings of spinal cord magnetic resonance imaging (MRI) and somatosensory evoked potentials (SEPs). Factor analysis of the sensory impairments showed two factors corresponding to superficial (pain and light-touch) and deep (position and 'thumb/big toe localizing') sensations. Vibratory sense depended on both Factors, but more on deep sensations. Multiple regression analysis of the SEP abnormalities and sensory deficits showed that impaired deep sensations contributed to abnormal SEPs, but the results of clinical sensory testings and SEPs were dissociated in 31% of the extremities examined. The MRI sagittal images correlated well with the Levels of sensory impairments, whereas the axial images showed a poor relationship to the extent of sensory impairments. We concluded that the use of SEPs as well as MRI is not always superior to such clinical sensory tests as the 'thumb/big toe localizing tests'. (C) 1998 Elsevjer Science B.V. All rights reserved.

To investigate the pathophysiological role of anti-GM1 antibody in Guillain-Barre syndrome (GBS), we reviewed sequential nerve conduction studies of 345 nerves in 34 GBS patients. Statistically significant correlation between IgG anti-GM1 antibodies and electrodiagnoses was found. Sixteen IgG anti-GM1-positive patients were classified as having acute motor or acute motor sensory axonal neuropathy (AMAN or AMSAN) (12 patients), as having acute inflammatory demyelinating polyneuropathy (AIDP) (3 patients), or as undetermined (1 patient) by electrodiagnostic criteria Besides axonal features, there was rapid resolution of conduction slowing and block. In 3 patients initially diagnosed as having AIDP, conduction slowing was resolved within days, and 1 of them and 3 AMAN patients showed markedly rapid increases in amplitudes of distal compound muscle action potentials that were not accompanied by prolonged duration and polyphasia The time courses of conduction abnormalities were distinct from those in IgG anti-GM1-negative AIDP patients. Rapid resolution of conduction slowing and block, and the absence of remyelinating slow components, suggest that conduction failure may be caused by impaired physiological conduction at the nodes of Ranvier. Reversible conduction failure as well as axonal degeneration constitutes the pathophysiological mechanisms in IgG anti-GM1-positive GBS. In both cases, immune-mediated attack probably occurs on the axolemma of motor fibers.

Eight of 32 patients (25%) with chronic inflammatory demyelinating polyneuropathy (CIDP) had micturitional disturbance, which consisted of voiding difficulty (n = 4), urgency (n = 4), or urgency incontinence (n = 1). Urodynamic studies on four symptomatic patients showed disturbed bladder sensation in two, bladder areflexia in one, and neurogenic changes of the external sphincter in one, indicative of peripheral parasympathetic and somatic nerve dysfunctions. Cystometry also showed detrusor overactivity in two patients but no evidence of CNS involvement, evidence that bladder overactivity occurs by probable pelvic nerve irritation.

A 47-year-old man showed progressive, symmetrical weakness in the limbs for 6 months. There was muscle atrophy, fasciculations, and acute denervation without motor conduction abnormalities below the elbows or knees: and motor neuron disease had once been suspected. However, compound muscle action potentials (CMAPs) after proximal stimulation showed an amplitude reduction between axilla and Erb's point for the median and ulnar nerves on both sides. His weakness as well as the amplitude reduction improved after administration of prednisolone. Demyelinative conduction abnormalities can be limited to the proximal segments for at least several months in a conduction equivalent to chronic inflammatory demyelinating polyneuropathy (CIDP). (C) 1998 Elsevier Science B.V. All rights reserved.

Objectives-To examine the frequency and pathophysiology of micturitional disturbance in patients with Guillain-Barre syndrome. Methods-Micturitional symptoms were noted and neurological examinations made repeatedly during admission to hospital of patients with clinical and neurophysiologically definite Guillain-Barre syndrome. Urodynamic studies consisted of uroflowmetry, measurement of residual urine, urethral pressure profilometry, medium fill water cystometry, and external sphincter EMG. Results-Seven of 28 (25%) patients with Guillain-Barre syndrome showed micturitional disturbance. The symptoms included voiding difficulty in six, urinary retention in three, nocturnal urinary frequency in three, and urge incontinence in two. These micturitional symptoms appeared after weakness occurred, and improved gradually along with the neurological signs. All three patients who showed retention became able to urinate. Urodynamic studies were made on four symptomatic patients two of whom underwent repeated study. Disturbed bladder sensation was noted in one patient, bladder areflexia in one, and absence of the bulbocavernosus reflex in one. Cystometry showed decreased bladder volume in two and bladder overactivity in two, one of whom had urge urinary incontinence and the other urinary retention. Conclusions-A quarter of the patients with Guillain-Barre syndrome tend to have micturitional disturbance. The patients studied had evacuation and storage disorders, as well as bladder areflexia and disturbed bladder sensation indicative of peripheral types of parasympathetic and somatic nerve dysfunction. Decreased bladder volume with bladder overactivity but no evidence of CNS involvement was also found, evidence that bladder overactivity also occurs in peripheral nerve lesions with probable pelvic nerve irritation.

The effects of long term melphalan-prednisorone (MP) therapy was studied on 12 patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome. Sin were treated with IMP every six weeks for 16 to 52 months; three also with cyclophosphamide, and three with localised irradiation for osteoclastic lesions. Five of the six survived during the follow up period and showed various degrees of lessening of their neuropathy and other symptoms. There were no serious side effects. The other six patients received treatments that included corticosteroids, short term chemotherapy; or irradiation, but not long term chemotherapy. Five showed transient lessening of their non-neurological symptoms, and one, obvious neurological improvement. Five of these six patients died from nine to 70 months after POEMS onset. The findings suggest that long term MP therapy may be an effective treatment for the POEMS syndrome.

The virus-associated hemophagocytic syndrome (VAHS) is a lymphoproliferative disorder induced by viral infection. The peripheral nervous system is rarely involved in this syndrome and, when reported, the involvement has been axonal in nature. This paper presents a case of Guillain-Barre syndrome accompanied by VAHS subsequent to Epstein-Barr virus infection. The patient's condition improved following treatment with intravenous immunoglobulin infusion and high-dose corticosteroids.

By recording the averaged potential from a microelectrode inserted into the nerve, small late components of the sensory nerve action potential can be analyzed. We studied the thresholds of the late components in median nerves of 15 normal subjects and 37 patients with peripheral neuropathies. Under normal conditions, the late components reflected the activities of small myelinated fibers which had high thresholds. In the patients with peripheral neuropathies, a part of the late components often had abnormally low thresholds, occasionally the lowest. The presence of low-threshold, late components was related to the pathologies of the different types of neuropathy and correlated with the numbers of regenerating clusters in sural nerve biopsies. These slowly conducting, low-threshold components may originate from regenerating or remyelinating fibers, and therefore should have prognostic value. (C) 1997 John Wiley & Sons, Inc.

Using MRI, we investigated the morphology and blood-nerve barrier function of the peripheral nerve trunk in 10 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Eight patients had a focal demyelinative segment in the median or ulnar nerve trunk that was defined by conduction block or abnormal temporal dispersion over a short distance. These demyelinative foci showed nerve enlargement with high signal intensity on proton or T-2-weighted images. In four patients with progressive illness or relapse, the enlarged segment showed gadolinium enhancement that disappeared during remission induced by immune therapies. The other four were in the steady phase and showed no gadolinium enhancement of the enlarged nerves. The two patients who showed conduction slowing, but no focal demyelinative focus, had neither nerve enlargement nor gadolinium enhancement. In CIDP, focal conduction abnormalities correlate well with anatomic changes that suggest intermittent, repeated inflammation associated with the breakdown of the blood-nerve barrier.

We describe two patients with unusual associated movements as a sequel to thoracotomy. The two patients developed involuntary twitchings of the latissimus dorsi, which were induced by contractions of the adjacent muscles, the serratus anterior muscle in patient 1 and the external intercostal muscle in patient 2, after lobectomy for lung cancer. Electrophysiological and radiological studies showed that aberrant regeneration from the adjacent nerves to the denervated latissimus dorsi could be responsible for the associated movements.

Plasma and cerebrospinal fluid (CSF) levels of C4d and the circulating immune complex (CIC) to Clq were measured in 12 patients with chronic inflammatory demyelinating polyneuropathy and Guillain‐Barré syndrome. CSF C4d values more than 2 SD from the mean of 8 cervical spongylosis cases were demonstrated in the patients with proximal demyelination. The CSF C4d probably originated from both intrathecal synthesis and the systemic circulation. CSF levels of C4d may serve as a sensitive indicator for the radicular involvement in demyelinating polyneuropathy. © 1995 Munksgaard

We investigated excitability of cervical lower motoneurons in 18 patients with juvenile muscular atrophy of the distal upper limb (Hirayama's disease), by F wave analysis and electrophysiological estimation of the number of motor units in the abductor pollicis brevis muscles of the affected side. In all the 18 patients, F wave persistencies and numbers of motor units were decreased, whereas amplitudes of single motor unit potentials were increased, compared to those of age-matched normal controls. Patients in a progressive phase showed markedly decreased F wave persistencies, overwhelming the degree of decreases in numbers of motor units. In half of them, F waves were significantly increased in number during neck flexion. On the other hand, patients treated with neck brace and patients having stabilized symptoms with longer duration showed F wave persistence reduction corresponded to the degree of the motor unit loss, and no changes in F wave persistencies in a posture of neck flexion. These results suggest that the disorder is characterized by decreased excitabilities of survived cervical anterior horn cells, as well as denervation and reinnervation, presumably resulting from local compression or circulatory failure by anterior shift of the posterior dural wall during neck flexion.

We found an electromyographical proof of reconstruction of the motor nerve terminals following hyperbaric oxygen therapy. A 38-year-old man who had been partially recovered for thirty four months from acute onset paraplegia following a gastrointestinal infection developed progressive muscular atrophy and weakness of the lower limbs, and was first admitted to our hospital. Cerebrospinal fluid examination was normal and nerve conduction studies showed small compound muscle action potentials without any evidence of segmental demyelination. There were ample fibrillation potentials on electromyography. Single fiber electromyography (SFEMG) showed increased fiber density, abnormal jitter and blockings without neurogenic jitter, which were similar to findings in post-poliomyelitis syndrome. He was treated by hyperbaric oxygen consisting of two hour exposures to pressures of two atmospheres breathing 100% oxygen. These exposures continued for a month daily, and thereafter once a week for one year. Clinical improvement of the weakness and a decrease in amount of fibrillation potentials occurred on and after a month after treatment. We found significant changes on SFEMG a year later. There were increased fiber densities and decreased mean values of consecutive differences. These changes indicate diminished degeneration and enhanced regeneration of the terminal axons. We think that hyperbaric oxygen has a benificial effect on oxygen metabolism of remaining motoneurons which may not be able to maintain excessive metabolic demands of all their sprouting axons.