Somatosensory evoked potentials in X-linked recessive bulbospinal neuronopathy: a case demonstration.

Clinicopathological findings in X-linked recessive bulbospinal neuronopathy were characterized by loss of myelinated fibers in the fasciculus gracilis and depletion of neurons in the ventral horn throughout the same segments. Clinical profile of this rare motor neuron disease include sign and symptom of lower motor neuron involving bulbar and spinal level with minimal or no sensory deficit. Previous electrodiagnostic findings consist of electrophysiological evidence of anterior horn cell disease and decreased or absent sensory action potentials in the peripheral nerve. The role of somatosensory evoked potential which can uncover the involvement of posterior column has never been probed. We report a 22-year-old man who had a clinical syndrome of X-linked bulbospinal neuronopathy. The peripheral electrodiagnostic studies supported the evidence of prolonged anterior horn cell disease and decreased sensory response. The median SEPs revealed delayed N11-N13 and N13-N20 interpeak latencies representing demyelination in fasciculus gracilis of upper cervical cord. Therefore, the median SEPs, an uninvasive procedure, can be used as a supportive method to identify sensory neuronopathy with posterior column lesion in this syndrome, especially when the patient has no obvious sensory and endocrine symptom.     

神经电生理检查在肌萎缩侧索硬化症中的应用

目的:观察神经电生理检查在肌萎缩侧索硬化症(amyotrophic lateral sclerosis,ALS)中的应用价值。方法:分别对28例临床确诊ALS、6例临床拟诊ALS、4例临床可能ALS患者进行4个区域的共8块肌肉肌电图(EMG)分析,四肢的磁运动诱发电位(MEP),上肢正中神经、尺神经、下肢胫神经F波检查,在双侧腓肠肌记录H波,四肢远端神经传导测定,包括运动传导速度(MCV)、感觉传导速度(SCV)、复合运动神经动作电位(CMAP)、感觉神经动作电位(SNAP)以及运动末梢潜伏期(DML)进行测定并分析,并与健康对照组30例进行比较。结果:临床确诊ALS的神经电生理测定各值异常均高于拟诊ALS和可能ALS(P<0.05),拟诊ALS和可能ALS组比较没有明显统计学差异。ALS组EMG异常率85%,MEP异常率72.4%,神经传导异常主要表现为CMAP降低36.2%,SCV基本正常,F波出波率下降33.3%,F波振幅增高26.3%,H波振幅增高26.3%。结论:EMG对ALS患者下运动神经元损害有定位诊断价值,EMG是ALS诊断的重要依据;MEP对ALS患者上运动神经元损害有诊断价值,但特异性不高;F波、H波对ALS患者上下神经元神经损害定位有补充诊断价值,神经传导测定用于ALS的鉴别诊断。     

An autopsy case of minamata disease (methylmercury poisoning)--pathological viewpoints of peripheral nerves

The outbreak of methylmercury poisoning in the geographic areas around Minamata Bay, Kumamoto, Japan in the 1950s has become known as Minamata disease. Based on earlier reports and extensive pathological studies on autopsied cases at the Kumamoto University School of Medicine, destructive lesions in the anterior portion of the calcarine cortex and depletion predominantly of granular cells in the cerebellar cortex came to be recognized as the hallmark and diagnostic yardstick of methylmercury poisoning in humans. As the number of autopsy cases of Minamata disease increased, it became apparent that the cerebral lesion was not restricted to the calcarine cortex but was relatively widespread. Less severe lesions, believed to be responsible for the motor symptoms of Minamata patients, were often found in the precentral, postcentral, and lateral temporal cortices. These patients also frequently presented with signs of sensory neuropathy affecting the distal extremities. Because of few sufficiently comprehensive studies, peripheral nerve degeneration has not been universally accepted as a cause of the sensory disturbances in Minamata patients. The present paper describes both biopsy and autopsy findings of the peripheral nerves in a male fisherman who died at the age of 64 years and showed the characteristic central nervous system lesions of Minamata disease at autopsy. A sural nerve biopsy with electron microscopy performed 1 month prior to his death showed endoneurial fibrosis and regenerated myelin sheaths. At autopsy the dorsal roots and sural nerve showed endoneurial fibrosis, loss of nerve fibers, and presence of Büngner's bands. The spinal cord showed Wallerian degeneration of the fasciculus gracilis (Goll's tract) with relative preservation of neurons in sensory ganglia. These findings support the contention that there is peripheral nerve degeneration in Minamata patients due to toxic injury from methylmercury.     

Neurophysiological investigation of cervical spondylosis

The difficulties in diagnosing spinal cord lesions due to the cervical spondylosis is well-known in clinical neurology. In order to investigate the contribution of various neurophysiological examinations in the diagnosis in cervical spondylosis, we examined 70 patients suffering from cervical spondylosis, with peripheral nerve conduction studies, F-wave from the upper limb and electromyography from the corresponding muscles, as well as somatosensory evoked potentials (SEPs) from upper and lower limbs. Patients were separated into four groups: 20 patients had cervical spondylosis symptoms only; 15 patients had symptoms and signs of spinal root involvement; 15 patients had symptoms and signs of myelopathy; and 20 patients had symptoms and signs of both myelopathy and spinal root involvement. A group of 20 normal controls was also studied. In all groups of patients SEPs were the most sensitive electrophysiological study. Low-amplitude N13 and increased conduction time of N9-N13 and central conduction N13-N19 and LP-P27 were the most common finding in SSEP testing. SEPs were affected in many cases without CT-MRI findings of spinal cord pressure. From the above findings, SEPs proved to be the most sensitive diagnostic investigation in cervical spondylosis.     

Cauda equina syndrome

Single or double-level compression of the lumbosacral nerve roots located in the dural sac results in a polyradicular symptomatology clinically diagnosed as cauda equina syndrome. The cauda equina nerve roots provide the sensory and motor innervation of most of the lower extremities, the pelvic floor and the sphincters. Therefore, in a fully developed cauda equina syndrome, multiple signs of sensory disorders may appear. These disorders include low-back pain, saddle anesthesia, bilateral sciatica, then motor weakness of the lower extremities or chronic paraplegia and, bladder dysfunction. Multiple etiologies can cause the cauda equina syndrome. Among them, non-neoplastic compressive etiologies such as herniated lumbosacral discs and spinal stenosis and spinal neoplasms play a significant role in the development of the cauda equina syndrome. Non-compressive etiologies of the cauda equina syndrome include ischemic insults, inflammatory conditions, spinal arachnoiditis and other infectious etiologies. The use of canine, porcine and rat models mimicking the cauda equina syndrome enabled discovery of the effects of the compression on nerve root neural and vascular anatomy, the impairment of impulse propagation and the changes of the neurotransmitters in the spinal cord after compression of cauda equina. The involvement of intrinsic spinal cord neurons in the compression-induced cauda equina syndrome includes anterograde, retrograde and transneuronal degeneration in the lumbosacral segments. Prominent changes of NADPH diaphorase exhibiting, Fos-like immunoreactive and heat shock protein HSP72 were detected in the lumbosacral segments in a short-and long-lasting compression of the cauda equina in the dog. Developments in the diagnosis and treatment of patients with back pain, sciatica and with a herniated lumbar disc are mentioned, including many treatment options available.     

Spinal cord tumors of the thoracolumbar junction requiring surgery: a retrospective review of clinical features and surgical outcome

PURPOSE: A retrospective review of medical records and imaging studies. To investigate characteristic clinical features and surgical outcomes of spinal cord tumors (SCTs) of the thoracolumbar junction (TLJ). The spinal cord transitions to the cauda equina in the TLJ. The TLJ contains the upper and lower motor neurons of the spinal cord and cauda equina. As a result, the clinical features of lesions in the TLJ vary, and these anatomical characteristics may affect surgical outcome. MATERIALS AND METHODS: Pathological diagnosis, clinical features, neurological signs, and surgical outcomes were investigated in 76 patients surgically treated at our institute for SCTs arising from T11 to L2. The patients were divided into epiconus (T11-12, n=18) and conus groups (L1-2, n=58). RESULTS: Patients in the epiconus group had hyperactive deep tendon reflexes (DTRs), while those in the conus group had hypoactive DTRs (p < 0.05). Nine patients were misdiagnosed with intervertebral disc diseases (IVDs) before correct diagnoses were made. It was impossible to definitively determine the exact cause of symptoms in four patients who had both SCTs and IVDs. CONCLUSION: Among SCTs of the TLJ, the epiconus group displayed upper motor neuron syndrome and the conus group displayed lower motor neuron syndrome. SCTs of the TLJ were frequently misdiagnosed as IVDs due to symptomatic similarities. SCTs of the TLJ should be included in differential diagnosis of back and leg pain, and it is highly recommended that routine lumbar magnetic resonance imaging include the TLJ.     

脊髓亚急性联合变性的临床特征与电生理检查

目的：评价脊髓亚急性联合交性(SCD)的临床特征与电生理检查的诊断价值。方法：回顾分析了16例SCD患的临床特点以及电生理检查等资料。结果：16例SCD患全部由维生素B12缺乏引起，慢性胃炎及胃大部切除术是其主要病因。肢体感觉异常、深感觉减退、感觉性共济失调及痉挛性截瘫是其主要症状和体征。11例患合并周围神经损害，1例脑白质受损。9例肌电图检查显示周围神经损害、8例SEP呈中枢传导受损，电生理检查均有阳性发现。7／12血清维生素B12浓度测定低于正常。结论：血清维生素B12浓度正常并不能完全排除SCD；电生理检查高度敏感，对SCD的早期诊断意义重大。     

The reorganisation of motor units in different motor neuron disorders

A study was made of the degree and sequence of neurophysiological changes during motor unit reorganisation in motor neuron disease (MND), spinal muscular atrophy (SMA), and prior polio. Concentric needle EMG was used in conjunction with our own computerized EMG-LAB system. Motor unit action potential (MUAP) parameters were measured in 543 muscles on weak and maximum effort. MUAP amplitude and area were found to increase in the early stages of damage, declining to normal or subnormal values in the course of the disease. It was concluded that in MND there is a pathological sequence: denervation--reinnervation--terminal denervation. The increase in MUAP amplitude and area in the early stages of lesion, reflecting reinnervation, was much greater in SMA than MND and most marked in prior polio. The eventual decrease is an expression of terminal decompensation.     

Distinct and overlapping alterations in motor and sensory neurons in a mouse model of spinal muscular atrophy

Motor neuron degeneration is the predominant pathological feature of spinal muscular atrophy (SMA). In patients with severe forms of the disease, additional sensory abnormalities have been reported. However, it is not clear whether the loss of sensory neurons is a common feature in severe forms of the disease, how many neurons are lost and how loss of sensory neurons compares with motor neuron degeneration. We have analysed dorsal root ganglionic sensory neurons in Smn-/-;SMN2 mice, a model of type I SMA. In contrast to lumbar motor neurons, no loss of sensory neurons in the L5 dorsal root ganglia is found at post-natal days 3-5 when these mice are severely paralyzed and die from motor defects. Survival of cultured sensory neurons in the presence of NGF and other neurotrophic factors is not reduced in comparison to wild-type controls. However, isolated sensory neurons have shorter neurites and smaller growth cones, and beta-actin protein and beta-actin mRNA are reduced in sensory neurite terminals. In footpads of Smn-deficient mouse embryos, sensory nerve terminals are smaller, suggesting that Smn deficiency reduces neurite outgrowth during embryogenesis. These data indicate that pathological alterations in severe forms of SMA are not restricted to motor neurons, but the defects in the sensory neurons are milder than those in the motor neurons.     

神经电生理检查在运动神经元病中的应用比较研究

目的：研究神经电生理检查在运动神经元病（MND）中的应用比较.方法：分别对50例MND患者进行4个区域的共8块肌肉肌电图（EMG）分析,四肢的磁运动诱发电位（MEP）,上肢正中神经、尺神经、胫神经F波检查,在双侧腓肠肌记录H波,四肢神经传导速度（NCV）被测定,并与健康对照组30例进行比较.结果：MND组中EMG失神经电位65.0％,轻力时限增宽62.5％,振幅增高52.8％,大力单纯或单混相60.0％; MEP中枢运动传导时间（CMCT）延长71.5％;F波出波率下降24.7％,F波增高26.0％;H波增高25.0％;复合运动神经动作电位（CMAP）降低27.3％,运动神经传导（MCV）减慢2.5％,感觉神经传导（SCV）减慢0.6％,感觉神经动作电位（SNAP）降低2.0％.结论：EMG对MND患者下运动神经元损害有定位诊断价值;MEP对MND患者上运动神经元损害有诊断价值;F波、H波对MND患者上下神经元神经损害定位有补充诊断价值,可作为损伤程度的评价标准;NCV测定帮助鉴别诊断.     

Neurologic recovery according to early magnetic resonance imaging findings in traumatic cervical spinal cord injuries

The aim of this study was to determine the usefulness of early magnetic resonance imaging findings in predicting neurologic recovery at or below the injured level in traumatic cervical spinal cord injuries. Thirty patients with traumatic cervical spinal cord injuries were included. All of the patients received a magnetic resonance imaging and a neurologic examination in the emergency room, within 7 days of injury and at 6 months following the injury. To quantify neurologic recovery below the injured level, we modified clinical scales, particularly the motor ratio and the sensory ratio. We used the neurologic level to quantify recovery around the injured level. We assessed neurologic recovery according to MRI patterns and lesion extents. The pure hemorrhagic MRI pattern was not observed. In edematous and mixed types, the improvement of neurologic levels was not significantly different. The motor ratio and sensory ratio improved significantly more in edematous type patients than in mixed type patients. Based on MRI lesion extent, the improvement of neurologic levels was not significantly different, and motor ratio and sensory ratio improved significantly more in those with one or two segments involved than in those with more than two segments involved. In conclusion, early MRI pattern and lesion extent after traumatic cervical spinal cord injury may provide important information to help predict neurologic recovery, especially below the injured level.     

运动神经元病的临床及神经电生理分析

目的:探讨本地区运动神经元病(MND)患者的临床表现及神经电生理特点。方法:对入选的21例MND患者进行肌电图(EMG)及神经传导检测(NCS),分析其临床特征及神经电生理特点。结果:在21例患者中,运动神经传导检测异常率为55.2%,主要表现为M波波幅降低;感觉神经传导正常率为98.85%。静息时发现纤颤电位18例(85.71%),正锐波16例(76.19%),束颤电位6例(28.57%),运动单位电位时限延长18例(85.71%),平均波幅增高10例(47.62%),大力收缩时表现为单纯相9例(42.86%)。其中上下肢肌肉的异常率为71.08%,胸锁乳突肌的异常率为92.31%,胸椎旁肌的异常率为33.33%。结论:神经电生理检查对MND的诊断非常重要,其中EMG检测是MND诊断的重要手段。EMG呈广泛性的运动神经元损害是MND的特征性改变,束颤电位在诊断中有重要价值。胸锁乳突肌阳性率高,可作为检查延髓节段下运动神经元受累的首选肌肉。     

A Korean case of juvenile muscular atrophy of distal upper extremity (Hirayama disease) with dynamic cervical cord compression

We present a Korean case of Hirayama disease with its typical neuroradiological findings of forward displacement of cervical dural sac and compression of the lower cervical cord during neck flexion. A 15-yr-old boy was presented with a one-year history of progressive weakness and atrophy affecting bilateral hands and forearms. The electrodiagnostic findings were compatible with the lesion of the anterior horn cells at the C7, C8, and T1 spinal segments. With neck flexion, cervical magnetic resonance imaging (MRI) showed the anterior shifting of the lower cervical dural sac resulting in the cord compression of those segments. Presumably, this disease might have been prevalent in Korea frequently under the diagnosis of "benign focal amyotrophy". In this regard, we discuss the clinical importance of cervical MRI with neck flexion and anticipate the increasing reports of the case substantiated by its characteristic radiological features.     

Immunohistochemical and ultrastructural studies of the various nuclei of the trigeminal complex in the human newborn.

The various nuclei of the trigeminal complex were studied by immunohistochemical (enkephalin localization) and ultrastructural means in the brainstems of eight newborn human babies that died within 24 h after birth. Positive enkephalin neurons were detected in the chief sensory and spinal trigeminal nuclei as well as in some fibers of the trigeminal nerve. Ultrastructurally, two morphologically distinct types of neuron were observed, respectively, in the motor nucleus, the spinal nucleus and the mesencephalic nucleus of the trigeminal complex, whereas three morphologically distinct types of neuron were observed in the chief sensory nucleus. "Glomerulus" formation was a frequently observed feature in the chief sensory nucleus. In the spinal nucleus, rolls of synaptic terminals stacking up one on top of another and synapsing onto the final synaptic element were very much in evidence. Axosomatic, axodendritic, dendrodendritic and dendroaxonic synapses were demonstrated in all the different nuclear areas of the trigeminal complex but axoaxonic synapses were absent in the mesencephalic nucleus. Some of the findings in the present human study were similar to those reported in the rats and cats.     

Vitamin B12 deficiency neurological syndromes: a clinical,MRI and electrodiagnostic study

BACKGROUND: Vegetarianism is an important cause of vitamin B12 deficiency, especially in countries like India. We managed 17 patients with neurological syndrome due to vitamin B12 deficiency in a tertiary care referral teaching hospital which caters to relatively affluent population. AIM: To evaluate neurophysiological and MRI changes in patients presenting with vitamin B12 deficiency neurological syndrome and interpret these is the light of reported autopsy findings. SETTING: Tertiary care referral teaching hospital. METHODS: Patients with vitamin B12 deficiency neurological syndrome diagnosed by low serum vitamin B12 and/or megaloblastic bone marrow were subjected to clinical evaluation and spinal MRI. The neurophysiological tests included nerve conduction studies, tibial somatosensory evoked potential (SEP), motor evoked potential (MEP) and visual evoked potential (VEP) studies. The recovery was defined on the basis of 6 months Barthel Index score into complete, partial or poor. RESULTS: There were 17 patients with vitamin B12 deficiency neurological syndrome, 3 were females and 12 lactovegetarian. The clinical syndrome was that of myelopathy in 8, myeloneuropathy in 5, dementia myelopathy in 3 and neuropathy in 1 patient. All the patients had impaired joint position and vibration sensation in the lower limbs and 4 had in upper limbs as well. Lower limbs were spastic in 13 and upper limbs in 2 patients. Spinal MRI revealed T2 hyperintensity in cervicodorsal region in 6 and cord atrophy in 3 patients. Sural nerve conduction was abnormal in 8 and peroneal conduction in 5 patients. In one patient all sensory nerve conductions were unrecordable but motor conductions were normal. Tibial SEP was abnormal in 12 out of 15 and lower limb MEP in 8 out of 12 patients. P100 latency of VEP was prolonged in 7 out of 13 patients. Right to left asymmetry was present in tibial SEP in 4 and VEP in 2 patients. At 6 months followup 2 patients improved completely, 7 partially and 3 had poor recovery. Clinical recovery correlated with MEP but not with SEP or MRI changes. CONCLUSION: The evoked potential and MRI changes in vitamin B12 deficiency neurological syndrome are consistent with focal demyelination of white matter in spinal cord and optic nerve. Myelopathic presentation is commoner and SEP is more frequently abnormal. The outcome at 6 months correlated with MEP changes.     

Neurophysiological assessment of peripheral neuropathy in primary Sjögren's syndrome

Peripheral nervous system complications are rare in patients with primary Sjögren's syndrome. We investigated a group of six women aged 43–64 years who complained of pain and sensory symptoms. Conventional neurophysiological tests reflecting large nerve fiber function revealed normal motor conduction in all patients, whereas sensory nerve action potentials were absent in two. On the other hand, quantitative thermometry and autonomic nerve function tests indicating small nerve fiber function were more sensitive in the assessment of nerve dysfunction; these showed abnormalities in all cases. Vibrametry showed dysfunctions in four patients. The latter methods possess great sensitivity in discovering sensory disturbances. Neurophysiological assessment of the sensory and autonomic nervous system demonstrating sensory neuropathy contributes to early diagnosis of primary Sjögren's syndrome.Abbreviations HRV heart rate variation - PNS peripheral nervous system - pSS primary Sjögren's syndrome - SSEP short-latency somatosensory evoked potentials - SSR sympathetic skin response - SuCV sudomotor nerve conduction velocity     

Electrophysiological findings in poliomyelitis patients at the subacute phase.

Electrodiagnostic tests-needle EMG, nerve conduction and somatosentory evoked potential (SEP) studies of the upper and the lower limbs were performed in three patients during the subacute phase of poliomyelitis. Although poliomyelitis is traditionally considered a "pure motor" disease, involvement of the sensory system was demonstrated by prolonged sensory nerve conduction and by delayed latencies and amplitude asymmetries of SEPs obtained from the lower limbs. Sensory deficit in poliomyelitis is well known to exist during the acute phase of illness. The present report describes the electrophysiological findings in patients during the subacute phase, several months after onset of illness. Sensory nerve action potentials and sensory evoked potentials were abnormal, especially those elicited by lower limb stimulation although the patients had no overt signs of sensory loss at that time. The associated EMG findings are described, and the probable pathologic changes of the motor unit are discussed.     

The pseudopolyneuritic form of amyotrophic lateral sclerosis (Patrikios' disease)

The line distinguishing motor neuron diseases (MNDs) from motor neuropathies is sometimes blurred. Among MNDs, the pseudopolyneuritic form of amyotrophic lateral sclerosis (ALS) strictly mimics a neuropathy. We describe the clinical and electrophysiological features in the early stages of the pseudopolyneuritic ALS, and assess the disease progression in eight patients. Early symptoms were unilateral foot-drop and, less commonly, paraparesis. At the clinical examination, weakness of distal and proximal leg muscles was often detected, while the hand muscles were rarely involved and craniobulbar muscles were spared. Definite upper motor neuron signs were rare in the early stages of the disease. Electromyography (EMG) showed active denervation in the lower limbs of all patients (distal > proximal) and in the paraspinal muscles of 7 patients (lumbosacral > thoracic), and more rarely in the upper limbs. Transcranial magnetic stimulation (TMS) yielded abnormal responses (low amplitude or absent cortical motor evoked potentials and prolonged central motor conduction time) in most lower-limb recordings, while mild abnormalities were rarely observed in the upper limbs. Haematologic and cerebrospinal fluid examinations were normal. Brain and spinal MRI showed no significant abnormalities. After a three years follow-up on seven patients, all cases were nonambulatory and had upper limb weakness, and most of them had bulbar dysfunction. The electrophysiological finding of both upper and lower motor neuron involvement of the lower limbs in the early stages of the disease could be a useful marker to distinguish the pseudopolyneuritic form of ALS from other MNDs and motor neuropathies.     

Peripheral neuropathy in spinal cord injured patients

We performed electrophysiological studies on the lower limbs of a group of clinically complete spinal cord injured patients. Our findings indicated a frequent asymmetric sensory and motor nerve involvement at proximal and distal sites. We suggest that mechanical compression and traction is one of etiological factors for such findings.     

Thalidomide therapy and polyneuropathy in myeloma patients

Thalidomide is today an increasingly used therapy in advanced and refractory myeloma patients, especially in patients relapsing after high dose therapy. One important and well-known side effect of thalidomide is polyneuropathy (PNP). The purpose of this study was to investigate 1) how severe the thalidomide-induced PNP is in patients treated for myeloma 2) which neurophysiological tests and parameters are most sensitive in detecting the thalidomide-induced PNP and 3) how neuropathic symptoms correlate with neurophysiological changes. Twelve patients received thalidomide for treatment of relapsed multiple myeloma for at least 5 months. Prior to the thalidomide treatment, all patients had been treated with chemotherapy including vincristine, and seven patients had also received cisplatin. PNP symptoms, clinical findings and neurophysiological tests before and after the therapy were evaluated. Prior to thalidomide treatment, 7 patients had minimal and one patient slight PNP. After thalidomide treatment, 4 patients had minimal, 4 patients slight, and 3 patients moderate PNP. Thalidomide-induced PNP mainly affected sensory myelinated axons, but also alpha motor neuron axons were affected to some extent. Thermal thresholds were not altered, indicating that thin myelinated and unmyelinated axons are spared. The most sensitive parameter for detecting thalidomide-induced PNP was the sensory nerve compound action potential amplitude. The neuropathic symptoms deteriorated significantly during the therapy, but clinically, no patient developed a disabling PNP that would have required interrupting the therapy. The neuropathic side effects of thalidomide seem to be acceptable in myeloma patients.