Sustained response to subcutaneous immunoglobulins in chronic ataxic neuropathy with anti-disialosyl IgM antibodies (CANDA): report of two cases and review of the literature.

INTRODUCTION: Chronic ataxic neuropathy with anti-disialosyl IgM antibodies (CANDA) is a rare disorder for which the pathological, neurophysiological, and therapeutic evidence remains anecdotal and controversial. METHODS: This report on CANDA focuses on the neurophysiological patterns and treatment responses shared by two cases. One patient underwent nerve ultrasound follow-up. A comprehensive review of the literature highlighted the diverse experiences with different treatment options. RESULTS: Response to different therapies was similar in both patients: intravenous immunoglobulins achieved a favorable response albeit with significant wearing-off fluctuations; treatment with subcutaneous immunoglobulins (SCIg) was an effective alternative leading to a clinical response for at least 2 years. Rituximab, which was trialed in both patients, was not continued long enough to determine its efficacy in modifying the disease course and/or modulating responsiveness to immunoglobulins. Steroids caused clinical worsening in both patients. CONCLUSIONS: Immunoglobulin therapy appeared as the most effective in the treatment of these two patients. SCIg provided an effective treatment option for the long-term management of CANDA.

Spasmophilia and entrapment nerve syndrome comorbidities in fibromyalgic patients: a possible neuromuscular pain generator.

This paper is aimed at investigating whether peripheral dysfunction at the neuromuscular level may represent a pain generator in fibromyalgia. We studied the prevalence of spasmophilia (SP), carpal tunnel syndrome (CTS) and ulnar neuropathy at the elbow (UNE) in a group of 40 subjects suffering from fibromyalgia. Clinical and electrophysiological data were obtained to ascertain whether comorbid conditions were present. For subjective evaluation of symptoms severity, validated questionnaires for CTS and UNE were completed by patients. Twenty subjects were positive for SP (50%); CTS was diagnosed in 12 subjects (30%); no patient suffered from UNE; 6 subjects were affected at the same time by SP and CTS (15%); 14 subjects (35%) were affected by SP alone. The prevalence of CTS and SP was higher in fibromyalgia subjects than in the general population. The scores of the questionnaires related to CTS were significantly higher in fibromyalgia subjects positive for CTS, with respect to the other subjects. In fibromyalgia, CTS and SP may be considered clinical entities in themselves, the importance of which lies in their acting as peripheral pain generators that enhance or initiate central sensitization, thereby contributing to chronic widespread pain. The amplification of pain is indeed a correctable/misguided message that occurs inside the brain of fibromyalgia subjects and identification and local treatment of pain generators would lessen the total pain burden. The magnitude of the overlap in symptoms between fibromyalgia and CTS/SP necessitates careful investigation of these conditions.

Reappraisal of the F/M amplitude ratio in carpal tunnel syndrome.

The F-wave/M-wave amplitude (F/M-amp) ratio has been shown to be increased in peripheral neuropathies, provided the maximum M-wave is relatively preserved. Reduced M-wave amplitudes and central facilitation of antidromically-induced reactivation of the anterior horn cells' axon hillocks (F-wave) are believed to contribute to higher F/M-amp ratios. The present study was undertaken to re-evaluate mechanisms responsible for higher F/M-amp ratios in carpal tunnel syndrome (CTS). We enrolled 232 cases affected by CTS and 108 controls. Fand M-wave amplitudes and F-wave chronodispersion were analyzed for the median and ulnar nerves. The F/M-amp ratio of the median nerve in CTS subjects with moderate-severe nerve damage was significantly higher than that of mild CTS subjects and controls. Chronodispersion of the median nerve F-wave increased with increasing CTS severity. We conclude that the relative preservation of the median nerve F-wave is due to damage to the large diameter muscle afferent fibers responsible for the monosynaptic response. Absence of the monosynaptic response makes the small motoneurons, usually inaccessible to the antidromic volley because of its collision with the orthodromic reflex volley, able to fire in the F-wave.

Listeria meningoencephalitis and anti-GQ1b antibody syndrome.

We report the first case of Listeria monocytogenes meningoencephalitis associated with anti-GQ1b antibody syndrome in an immunocompetent adult. A prompt diagnosis, made thanks to the multidisciplinary contribution, allowed a combined therapeutic approach leading to final favourable outcome, despite several intercurrent complications.

Clinical findings and electrodiagnostic testing in 108 consecutive cases of lumbosacral radiculopathy due to herniated disc.

STUDY AIM: This prospective study aim to examine whether clinical findings and electrodiagnostic testing (EDX) in patients with lumbosacral monoradiculopathy due to herniated disc (HD) differ as a function of root involvement level (L5 vs. S1) and HD zone (paramedian vs. intraforaminal). PATIENTS AND METHODS: All patients with L4, L5 or S1 monoradiculopathy were prospectively enrolled at four electromyography (EMG) labs over a 2-year period. The diagnosis was based on a congruence between patient history and MRI evidence of HD. We compared the sensitivities of clinical findings and EDX with respect to both root involvement level and HD zone. Multivariate logistic regression was performed in order to verify the association between abnormal EMG, clinical, and neuroradiological findings. RESULTS: One hundred and eight patients (mean age 47.7 years, 55% men) were consecutively enrolled. Sensory loss in the painful dermatome was the most frequent finding at physical examination (56% of cases). EMG was abnormal in at least one muscle supplied by femoral and sciatic nerves in 45 cases (42%). Inclusion of paraspinal muscles increased sensitivity to only 49% and that of proximal muscles was useless. Motor and sensory neurography was seldom abnormal. The most frequent motor neurographic abnormalities were a delay of F-wave minimum latency and decrease in the compound muscle action potential amplitude from extensor digitorum brevis and abductor hallucis in L5 and S1 radiculopathies, respectively. Sensory neurography was usually normal, the amplitude of sensory nerve action potential was seldom reduced when HD injured dorsal root ganglion or postganglionic root fibres. Multivariate logistic regression analysis showed that EMG abnormalities could be predicted by myotomal muscular weakness, abnormal deep reflexes, and paraesthesiae. The only clinical and electrophysiological differences with respect to root involvement level concerned deep reflexes and motor neurography of deep peroneal and tibial nerves. CONCLUSIONS: Only some EDX parameters are helpful for the diagnosis of lumbosacral radiculopathy. EMG was abnormal in less than 50% of cases and its abnormalities could be predicted by some clinical findings. However, neurography is useful as a tool for differential diagnosis between radiculopathy and more diffuse disorders of the peripheral nervous system (polyneuropathy, plexopathy).

Sensory nerve action potential amplitude is rarely reduced in lumbosacral radiculopathy due to herniated disc.

OBJECTIVE: Normal sensory nerve action potential (SNAP) amplitude is a classical neurographic rule whether damage is located proximal to the dorsal root ganglion (DRG) as in radiculopathy. The study's aim is to check SNAP reduction in patients with lumbosacral radiculopathy due to herniated disc (HD). METHODS: A total of 108 consecutive patients with lumbosacral monoradiculopathy were prospectively enrolled. The diagnosis was based on clinical findings and magnetic resonance imaging (MRI). Electromyography of muscles of L4-S1 myotomes, motor neurography of peroneal and tibial nerves and sensory neurography of saphenous, superficial peroneal and sural nerves were performed. Percentage decrease in SNAP amplitude of nerves between healthy and affected sides was calculated. RESULTS: Significant SNAP amplitude asymmetry was observed in superficial peroneal nerve in seven patients with L5 (12.1%) and in sural nerve in one patient with S1 (2.4%) radiculopathies. All these patients had foraminal HD. CONCLUSIONS: SNAP amplitude reduction of sensory nerve originating from damaged root is present only in 7% of radiculopathies and is likely due to DRG compression when located proximal to the spinal foramen or within the intraspinal canal. SIGNIFICANCE: Preservation of SNAP amplitude in radiculopathy remains an electrophysiological dogma with a little exception. If the reduction of SNAP amplitude affects other nerves, causes other than radiculopathy should be sought.

Polyneuropathy in cerebrotendinous xanthomatosis and response to treatment with chenodeoxycholic acid.

Polyneuropathy has been reported in cerebrotendinous xanthomatosis (CTX), although its nature and possible association with certain genotypes and phenotypes are unclear. The effect of chronic administration of chenodeoxycholic acid (CDCA) on peripheral nerve conduction parameters is still debated. We report clinical, laboratory, and electrophysiological findings in 35 CTX patients. Twenty-six subjects (74.2 %) showed peripheral nerve abnormalities. Polyneuropathy was predominantly axonal (76.9 % of patients) and generally mild. No correlation was found between its presence and clinical or biochemical data. In polyneuropathic patients, CDCA treatment improved electrophysiological conduction parameters, irrespective of the duration of therapy. Improvement mainly concerned nerve conduction velocities, whereas most nerve amplitudes remained unchanged. This means that CDCA treatment did not influence the number of axons activated by maximum electrical stimulation but increased the conduction of the still-excitable fibers. Our findings may suggest that CDCA treatment promotes myelin synthesis in nerve fibers with residual unaffected axons. The effect of therapy may therefore depend largely on the extent of irreversible structural damage to axons.

Acute shoulder-girdle neuralgic amyotrophy (Parsonage-Turner syndrome with saphenous nerve involvement.

Parsonage-Turner syndrome (PTS) is a relatively rare cause of upper extremity weakness and pain. There is currently no effective treatment for PTS although corticosteroids are recommended. Here we report the case of a man with acute PTS and exceptional involvement of both saphenous nerves, advantageously treated with intravenous immunoglobulin.

Prevalent involvement of thenar motor fibres in vineyard workers with carpal tunnel syndrome.

OBJECTIVE: Carpal tunnel syndrome (CTS) has a high prevalence in agricultural workers, especially those engaged in vineyards. We postulated that vineyard CTS was electrophysiologically different from CTS of other subjects. We performed a retrospective cross-sectional electrophysiological study of two cohorts of consecutive patients with CTS, the first consisting of vineyard workers and the second, of other unselected types of workers, housewives and pensioners. METHODS: Thirty-three vineyard workers (mean age 46.8years, 42% women) and 205 patients with other occupations (mean age 53.7years; 66% women) were enrolled. All patients underwent sensory and motor neurography of the median and ulnar nerves. Differences in demographic and electrophysiological findings between groups were calculated and multiple linear regression analysis was performed to eliminate the influence of potential confounding factors (age, sex, BMI, clinical severity of CTS) on the results of univariate difference analysis. RESULTS: Univariate analysis showed that DML was longer and compound muscle action potential amplitude of the median nerve, recorded from the abductor pollicis brevis muscle, was smaller in vineyard workers than in the other CTS patients. These differences remained significant after adjusting the results for confounding factors. CONCLUSIONS: The vineyard workers showed a different pattern of CTS than the other patients: thenar motor fibres were more affected, presumably due to chronic compression on the thenar branch. This suggests an association between "common" CTS and thenar mononeuropathy. SIGNIFICANCE: Occupational physiologists should clarify the mechanisms of neuromuscular engagement in particular jobs and ergonomists design suitable working tools, because many "individual" risk factors are difficult to change, but workplace-related risk factors can be modified.

Ultrasonographic and functional changes of the ulnar nerve at Guyon's canal after carpal tunnel release.

OBJECTIVE: To describe morphologic and functional modifications of the ulnar nerve at the wrist in carpal tunnel syndrome (CTS) after carpal tunnel release (CTR). METHODS: Ultrasonography was used to study the cross sectional area (CSA) of the ulnar nerve at Guyon's canal, before and 1 and 6 months after CTR, in 18 CTS patients. A parallel electrophysiological and clinical analysis was also conducted. RESULTS: CSA of the ulnar nerve significantly increased 6 months after CTR. Ten (55%) cases showed abnormal CSA values compared to a control group before surgery and five (28%) at 6 month follow-up. In addition, there were improvements in the motor and sensory ulnar axon recruitment properties and the conduction values in sensory ulnar fibres. Patients with extra-median distribution of paresthesia (4 subjects) were free from symptoms. CONCLUSIONS: CTR has a significant effect not only on the anatomical geometry of Guyon's canal, but also on the morphology and function of the ulnar nerve. SIGNIFICANCE: In CTS, high pressure in the carpal tunnel may result in anatomical changes of ulnar nerve, thus causing functional impairment to the ulnar fibres. CTR appears to reverse some of this damage.

Multiple arm lipomatosis and posterior interosseus nerve palsy.

BACKGROUND: Lipomas are common benign soft tissue tumours which tend to be indolent and risk free. Lipomas rarely spread in the deep soft tissue causing posterior interosseous nerve (PIN) neuropathy. METHODS (CASE DESCRIPTION): We present two patients with multiple lipomatosis of the arms and PIN paralysis, with a brief review of the cases reported in literature. RESULTS AND CONCLUSION: We emphasize the role of electromyographic study as unique methodical capable to reveal an early radial nerve damage, permitting an optimal post-surgical nerve function recovering.

Anomalies of ulnar nerve conduction in different carpal tunnel syndrome stages.

Impairment of ulnar sensory fibers at the wrist has recently been documented in moderate/severe carpal tunnel syndrome (CTS). This has been interpreted as a consequence of compressive forces transmitted to Guyon's canal by high pressure in the carpal tunnel or comorbidity between ulnar neuropathy and CTS. The main aim of the present study was to identify any ulnar nerve conduction impairment in the early stages of CTS. The relation between ulnar and median nerve conduction in all CTS severity stages was also assessed. Ulnar nerve sensory conduction at the wrist was investigated in 580 hands with CTS. Significant changes in ulnar nerve conduction were present even in the early stages of CTS. A significant, positive correlation was also found between CTS severity and conduction abnormalities of ulnar sensory fibers. These findings make the hypothesis of comorbidity weak. Based on the above results and on reports of high pressure in Guyon's canal in CTS, ulnar nerve conduction abnormalities may be caused in part by compressive forces progressively transmitted to the canal by increasing pressure in the carpal tunnel with increasing CTS severity. This does not exclude other causative factors such as subclinical traumatic damage acting on median and ulnar fibers.

Arachnoid cyst and arachnoiditis following idiopathic spinal subarachnoid haemorrhage.

We describe 8 years follow-up of a case of arachnoid cyst developing after spinal subarachnoid haemorrhage. The cyst was removed by hemilaminectomy; an arachnoid cyst of the same size was again observed by MRI 2 weeks later. We suggest that conservative approach could be the best choice.

Evidence of altered motor axon properties of the ulnar nerve in carpal tunnel syndrome.

OBJECTIVE: To analyse recruitment properties of ulnar nerve motor axons in 60 CTS patients with negative ulnar nerve electrodiagnostic tests. METHODS: Recruitment properties of the ulnar nerve were studied by analysing the relationship between the intensity of electrical stimulation and the size of motor response, i.e. the stimulus-response curve. Parameters of the curve (threshold, slope and plateau) were compared with those of the corresponding curve of the median nerve and both with parameters of 30 control curves. RESULTS: The ulnar nerve stimulus-response curve was strikingly abnormal and, except for severity, closely resembled that of the median nerve. The slope of the curve was significantly less than that of controls and decreased with increasing abnormalities of the median nerve. This suggested that the pathological process involving the ulnar nerve was contingent with the severity of median nerve involvement. CONCLUSIONS: We propose that the ulnar nerve may be subject to compression in Guyon's canal as a consequence of high pressure in the carpal tunnel of CTS patients. SIGNIFICANCE: Ectopic activity from ulnar axons may contribute to clinical spread of symptoms outside the median nerve territory in CTS. This does not exclude possible involvement of central plasticity mechanisms in producing extra-median symptoms in CTS patients.

Changes in the recruitment curve of the soleus H-reflex associated with chronic low back pain.

OBJECTIVE: We investigated whether patients with chronic low back pain (CLBP) manifest changes in the excitability of the soleus H-reflex. METHODS: H-reflex stimulus-response curve was studied in 14 CLBP patients and 14 age-matched healthy subjects. H-threshold, H-maximum size, H-steepness and H-latency were determined for both legs. Homosynaptic depression (HD), following a train of H-reflexes, and presynaptic inhibition (PI) from flexor afferents onto soleus Ia afferents were also evaluated. RESULTS: H-threshold was significantly increased, H-size as a function of stimulus intensity was significantly different, and H-recruitment curve steepness was significantly lower in CLBP patients compared to healthy subjects. No significant difference in the amount of HD and PI of the H-reflex was found between the two groups. H-latency and Hmax/Mmax ratio was comparable between the subjects groups. CONCLUSIONS: In CLBP there is a reduced excitability of group Ia afferent fibres from the soleus muscle to which presynaptic factors do not seem to contribute and that presumably depend on changes in the peripheral sensory input. SIGNIFICANCE: Changes in H-reflex excitability may underlie a decrease in the gain of a peripheral sensor in CLBP. Estimation of soleus H-threshold and H-recruitment curve may contribute to the diagnostic evaluation of CLBP and may be used to monitor the efficacy of treatment.

Changes in motor axon recruitment in the median nerve in mild carpal tunnel syndrome.

OBJECTIVE: To determine whether patients with mild carpal tunnel syndrome (CTS) and conventional electrodiagnostic evidence of selective involvement of sensory conduction show changes in motor axon recruitment in the median nerve. METHODS: Wrist-to-abductor pollicis brevis (APB) motor axon conduction was studied by analysing the relationship between the intensity of electrical stimulation and the size of motor response (input-output curve) in 30 CTS patients with conventional electrodiagnostic evidence of selective involvement of sensory conduction. Parameters (threshold, slope and plateau) of input-output curves were compared with those obtained in 30 controls. RESULTS: The slope of the input-output curve of CTS patients was less steep than that of controls. For stimulus intensity above M-wave threshold (MTh), fewer motor axons were recruited in patients than controls. CONCLUSIONS: Motor fibres are affected in CTS when conventional electrodiagnostic tests show normal motor conduction. Altered recruitment of motor axons could mainly be due to impairment of energy-dependent processes which affect temporal dispersion of the compound volley or axonal conduction block. SIGNIFICANCE: In mild CTS, motor fibres are more often affected than was originally thought. The sensitivity of wrist-to-APB motor conduction studies may be increased by using submaximal stimulus intensities.

Changes in coordination of postural control during dynamic stance in chronic low back pain patients.

The human postural system operates on the basis of integrated information from three independent sources: vestibular, visual and somatosensory. It is conceivable that a derangement of any of these systems will influence the overall output of the postural system. The peripheral proprioceptive system or the central processing of proprioceptive information may be altered in chronic low back pain (CLBP). We therefore investigated whether patients with CLBP exhibited an altered postural control during quiet standing. Dynamic posturography was performed by 12 CLBP patients and 12 age-matched controls. Subject's task was to stand quietly on a computer-controlled movable platform under six sensory conditions that altered the available visual and proprioceptive information. While the control of balance was comparable between the two groups across stabilized support surface conditions (1-3), CLBP patients oscillated much more than controls in the anterior-posterior (AP) direction in platform sway-referenced conditions (4-6). Control experiments ruled out that increased sway was due to pain interference. In CLBP patients, postural stability under challenging conditions is maintained by an increased sway in AP direction. This change in postural strategy may underlie a dysfunction of the peripheral proprioceptive system or the central integration of proprioceptive information.

Sex differences in carpal tunnel syndrome: comparison of surgical and non-surgical populations.

Carpal tunnel syndrome (CTS) patients are known to show gender-related differences in severity. The main aim of this cross-sectional study was to determine whether these differences between women and men may be related to age, education or body mass index (BMI) in two populations, one with idiopathic CTS not treated surgically and the other with idiopathic CTS treated by surgical decompression. A secondary aim was to check differences in surgical results between the genders in the surgical population. The non-surgical population consisted of 172 subjects (126 women and 46 men, mean age 55.1 years) whose data were obtained at electrophysiological examination. The surgical population consisted of 219 patients (177 women and 42 men, mean age 55.1 years) whose data were obtained before surgery. Age, education, BMI, duration of symptoms, electrophysiological and clinical severity of CTS (with ordinal scales), and the self-administered Boston Questionnaire (BQ) of symptoms and functional status of hands were considered. There were no differences in age or clinical and electrophysiological severity between women and men in either group, except for distal motor latency of the median nerve that was more delayed and duration of symptoms that was shorter in men than women in non-surgical sample. Men had a higher BMI than women. Women had higher BQ scores in the surgical and non-surgical samples. These differences remained when the results were analysed matching the men with an identical number of women of the same age, education and BMI. In the surgical population, the results of surgical decompression did not modify the gender-related differences in severity. As in many other syndromes and diseases, for a given clinical severity, women with CTS were more sensitive than men in reporting their symptoms. Risk factors of CTS, such as age, education and BMI, were not responsible for these differences. The results of surgical decompression were similar in men and women.

Cortico-motoneuronal output to intrinsic hand muscles is differentially influenced by static changes in shoulder positions.

We investigated whether shoulder position influenced the recruitment properties of the abductor digiti minimi muscle (ADM) and first dorsal interosseous muscle (FDI). ADM and FDI motor evoked potentials (MEPs) in response to transcranial magnetic stimulation (TMS) were obtained in seven healthy volunteers at two different static positions of the shoulder joint (30 degrees adduction vs 30 degrees abduction) while the arm was passively supported at shoulder level (90 degrees in the horizontal plane) and the elbow joint was fixed at 90 degrees . ADM and FDI voluntary activity was also examined during (1) externally paced finger abductions at 2 Hz in the two different shoulder positions (EMG(ADM) and EMG(FDI) was back-averaged time-locked to the end of finger abduction) and (2) maximal voluntary abduction of the little finger and the index finger. Maximal EMG power and force were analysed in the two shoulder positions. H-reflexes from ADM and FDI were also obtained in two subjects. The ADM stimulus-response curve to TMS showed that the slope and plateau level were significantly reduced with the shoulder at 30 degrees abduction. In contrast, the FDI stimulus-response curve to TMS was not influenced by shoulder position. The back-averaged EMG(ADM) showed a significant decrease in peak amplitude and area with the shoulder at 30 degrees abduction, while no change in EMG(FDI) was observed under the same condition. Similarly, maximal EMG(ADM) and force exertion by the little finger were significantly reduced with the shoulder at 30 degrees abduction, while no such effect was observed for FDI. ADM H-reflex, but not FDI, was also decreased with shoulder abduction. These results indicate that the corticospinal pathway to ADM is less accessible to TMS and to voluntary command when the shoulder is placed at 30 degrees abduction. In contrast, activation of FDI, whether by TMS or by volition, is not influenced by shoulder position. This finding suggests that there are differences in the corticospinal innervation to ADM and FDI, possibly due to the different role of these muscles in hand function.