91例肌萎缩侧索硬化症的F波和神经传导研究

目的探讨肌萎缩侧索硬化症(ALS)F波和神经传导改变的特点.方法所有患者均采用常规方法测定感觉神经传导速度(SCV)、运动末端潜伏期(distal motor latency,DML)和F波,后者的测定包括潜伏期和/或传导速度及出现率.分析了DML和复合肌肉动作电位(compound muscle action potential,CMAP)波幅、F波出现率与肌力的关系.结果在91例ALS患者中,仅有3例SCV异常;正中神经、尺神经及胫后神经DML延长者分别占16.7%、13.8%、7.1%,CMAP波幅下降者分别占50.0%、44.6%、28.6%;5.0%患者F波传导速度异常,48例患者F波出现率下降,其中19例出现率为0.肌力下降者DML、CMAP波幅及F波出现率改变明显.结论ALS患者可出现DML延长和CMAP波幅降低,二者比较后者的改变更显著;F波传导速度相对正常而出现率下降明显;DML、CMAP波幅及F波出现率的异常与肌力明显相关(P均＜0.01).     

肌萎缩侧索硬化患者205例的神经传导特点分析

目的 分析肌萎缩侧索硬化(ALS)患者的神经传导和F波特点,并探讨其与肌力、病程和首发部位等之间的关系.方法 收集于1997年1月至2008年5月期间我院门诊或病房收治的ALS患者205例,均采用常规肌电图检查,测定其运动神经传导、F波以及感觉神经传导(SCV).结果 在205例ALS患者中,仅有3例SCV异常,正中神经、尺神经及胫后神经末端潜伏期(DML)延长者分别占24.9%(48/193)、15.3%(25/163)、21.2%(7/33),复合肌肉动作电位(CMAP)波幅下降者分别占57.0%(110/193)、49.7%(81/163)、39.4%(13/33);68.9%(122/177)患者F波出现率下降,其中31.1%(55/177)F波出现率为0,肌力下降者DML、CMAP波幅及F波出现率改变明显.肢体起病组正中神经CMAP波幅下降[81.5%(53/65)]和F波异常率[70.9%(44/62)出现率下降,45.1%(28/62)出现率为0]较延髓部起病者[32.4%(11/34);F波38.2%(13/34)出现率下降,14.7%(5/34)出现率为0]更明显,两组比较差异有统计学意义(x2=23.629、9.753、9.029,均P<0.01);DML异常两组间差异无统计学意义.Logistic回归分析显示CMAP波幅的降低与上肢远端肌力、首发部位、病程显著相关,F波出现率的降低与上肢远端肌力、首发部位相关.结论 ALS患者可出现DML延长和CMAP波幅降低(后者改变更显著),F波出现率明显下降而传导速度相对正常;DML、CMAP波幅及F波出现率的异常与肌力明显相关.首发部位为肢体和(或)上肢远端肌力下降者CMAP波幅及F波异常率更明显.

Abstract：

Objective To investigate the F-wave and nerve conduction in patients with amyotrophic lateral sclerosis (ALS) and explore the correlation between these parameters and muscle strength, disease duration and onset site.Methods The data of outpatients and inpatients diagnosed with ALS were collected in Peking Union Medical College Hospital from January 1997 to May 2008.Standard sensory and motor nerve conduction study of the median nerve, ulnar nerve and tibial nerve was performed in 205 patients with ALS.F-wave velocity and frequency was measured in median nerve.Parameters for analyses included sensory conduction velocity and amplitude, distal motor latency (DML), and compound muscle action potential (CMAP) amplitude.Correlation between muscle strength and DML, CMAP amplitude or F-wave frequency were also explored.Results Delayed DML of the median nerve, ulnar nerve and tibial nerve were found in 24.9% (48/193), 15.3% (25/163), 21.2% (7/33) of patients respectively.Decreased CMAP amplitudes were found in 57.0% (110/193), 49.7% (81/163), 39.4% (13/33) of patients respectively.Decreased F-wave frequency of the median nerve was found in 68.9% (122/177) of patients.The abnormality of DML,CMAP amplitude and F-wave frequency of median nerve were increased in weaker muscles.Decreased median nerve CMAP amplitude (81.5% (53/65)) and F-wave abnormality (decreased persistence 70.9%(44/62), absent responses 45.1% (28/62)) in spinal onset groups were significantly higher than those in bulbar onset groups (CMAP 32.4% (11/34); F-wave: decreased persistence 38.2% (13/34), absent responses 14.7% (5/34); x2 = 23.629, 9.753, 9.029,all P <0.01).Compared with the bulbar onset group,the abnormality of DML in spinal onset group was higher, but not reach statistical significance.Logistic regression revealed a strong direct association between decreased CMAP amplitudes and upperextremity muscles strength, disease duration and onset symptom.Abnormality of F-wave frequency was associated with upper-extremity muscles strength and onset symptom.Conclusions Delayed DML and decreased amplitude of CMAP are found in ALS patients.CMAP amplitude is a sensitive parameter related to the severity of ALS.F-wave velocity is relatively normal while F-wave frequency of the median nerve is correlated with muscle strength.Decreasing CMAP amplitude and F-wave frequency are correlated strongly with muscle weakening,disease duration and symptom onset over limbs.     

Significant CMAP decrement by repetitive nerve stimulation is more frequent in median than ulnar nerves of patients with amyotrophic lateral sclerosis

Introduction: Several studies have shown a significant amplitude decrement in compound muscle action potentials (CMAPs) on repetitive nerve stimulation (RNS) of muscles involved in amyotrophic lateral sclerosis (ALS).In ALS, muscle wasting preferentially affects the thenar muscles (APB) rather than the hypothenar muscles (ADM). Methods: We performed RNS studies in the APB and ADM muscles of 32 ALS patients to determine whether the effect of RNS differs between the median and ulnar nerves. Results: The decremental responses to RNS were greater in the APB than in the ADM. Reduced CMAP amplitude was negatively correlated with CMAP decrement in median but not in ulnar nerves. Conclusions: The greater CMAP decrement in median nerve is attributable to preferential involvement of the APB in the pathophysiology of ALS or some underlying difference in the biology of the two muscles/nerves. Further investigations will better our understanding of the pathophysiology of ALS. Muscle Nerve, 2012     

F-wave amplitude in peripheral nervous system lesions

BACKGROUND AND PURPOSE: F-wave is a late response recorded from muscle elicited by electric impulse conveyed antidromically to alpha-motor neurons of the spinal cord. F-wave latency and frequency are assessed in routine electroneurography providing information of conduction in the proximal segment of the nerves. F-wave amplitude is rarely analyzed, while it could add valuable information on excitability of motor neurons in different disease states. This study was conducted to determine whether F-wave amplitude is indicative of the level of the peripheral nervous system lesion. MATERIAL AND METHODS: EMG recordings of 204 consecutive patients suspected of peripheral nerves system lesion were retrospectively analyzed. Based on the clinical diagnosis three groups were defined: neuropathy (N=100), myopathy (N=33), ALS (N=18), reference (musculoskeletal pain syndromes: N=53). F-wave amplitude and F/CMAP-ratio (CMAP-compound motor action potential) and their relation to parameters of impulse conduction in motor nerve fibers was analyzed. RESULTS: Mean F/CMAP ratio was 11.1% in ALS, 5% in myopathy (p=0.008), 7.1% in neuropathies and 5.6% in the reference group. Giant F-wave (more than 10% of CMAP) was observed in 30% of nerves in ALS, 15% in neuropathy and 10% in myopathy (p=0.036). F-wave amplitude correlated significantly with CMAP amplitude in all groups, while F/CMAP ratio was inversely related to CMAP amplitude in ALS (r=-0.43, p<0.01) and neuropathy (r=-0.37, p<0.0001). F-wave frequency was similar in all groups and correlated with CMAP amplitude. CONCLUSIONS: F-wave amplitude is not indicative of the level of peripheral nervous system lesions. Giant F-wave is observed in neurogenic processes. It reflects an increase of motor unit size in the reinnervation process, but possibly also a change of excitability of motor neuron and its axon.     

Effects of prolonged repetitive stimulation of median,ulnar and peroneal nerves

It is important to know the effects of prolonged repetitive nerve stimulation (RNS) when it is used in neurophysiological studies. RNS with up to 100 supramaximal stimuli was given to the median, ulnar, and peroneal nerves of normal subjects and the ulnar nerves of subjects with early amyotrophic lateral sclerosis (ALS), recording evoked compound muscle action potentials (CMAPs). In all nerves, there was a decline in the CMAP area and a decrease in CMAP duration. For the peroneal nerve there was a decline in the CMAP amplitude, but a similar decline was not seen in the median or ulnar nerves. Cooling of the muscles resulted in decrement of both the amplitude and area with RNS. In ALS subjects, CMAP amplitude and area both declined after RNS of the ulnar nerve. In this study we describe the changes in CMAP with prolonged RNS among commonly tested normal nerves. Our findings have important implications with regard to RNS. Muscle Nerve, 2010     

Reproducibility of neurophysiological and myometric measurement in the ulnar nerve-abductor digiti minimi system

Reliability in strength and neurophysiological measurements is important in evaluating progression of neuromuscular diseases. No data are available on the variability of neurophysiological parameters as compared with maximal voluntary isometric contraction (MVIC) in the same muscles, in healthy subjects. A control population of 26 healthy subjects was studied twice on different days. We evaluated the reliability of neurophysiological parameters obtained from bilateral ulnar nerve stimulation, recording the response over the abductor digiti minimi (ADM) muscle, including distal motor latency, compound muscle potential amplitude and area, F-wave frequency and mean F-wave latency, and the derived neurophysiological index that we have described previously. MVIC force was measured in each session in both ADM muscles. The variances between the grouped data obtained in the two recording sessions were identical, indicating a low intrinsic variability with this experimental methodology. Comparison of the mean values obtained in the two sessions revealed no statistically significant differences. The reliability of these neurophysiological and strength measurements in the same nerve/muscle system suggests they may be useful in comparing the dynamics of weakness and neurophysiological change in neuromuscular disease.     

Transcutaneous cervical root stimulation in the diagnosis of multifocal motor neuropathy with conduction block

OBJECTIVES: To determine if transcutaneous electrical stimulation of the cervical roots can be used to diagnose proximal conduction block (CB) in multifocal motor neuropathy (MMN) and whether it can reliably distinguish MMN from amyotrophic lateral sclerosis (ALS). METHODS: Compound muscle action potentials (CMAPs) over the abductor digiti minimi (ADM) were evoked by supramaximal stimulation of the ulnar nerve at the wrist, below elbow, above elbow, axilla, Erb's point, and C8/T1 cervical roots in three groups of patients: 31 patients with ALS, nine patients with MMN, and 31 controls. Supramaximal stimulation at Erb's point and the C8/T1 roots was carried out using a transcutaneous high voltage electrical stimulator. The negative peak amplitude, area, and duration of the CMAP were measured and normalised to that from the wrist. The percentage change in each segment in these parameters was calculated and compared between the different groups. RESULTS: At stimulation sites proximal to the elbow, there were no significant differences in relative CMAP amplitude, area, or duration between controls, ALS patients, and MMN patients with clinically unaffected ulnar nerves. Similarly, the percentage segmental change between adjacent stimulation sites showed no significant differences. In six studies of MMN patients with weakness in ulnar hand muscles, the decrease in CMAP amplitude between the C8/T1 roots and Erb's point exceeded the mean + 2 SD of the control data. CONCLUSION: Cervical root stimulation can quantify CB in the most proximal segment of the ulnar nerve, a fall in CMAP amplitude if greater than 25%, indicating block, and should be used routinely in the evaluation of patients suspected of having MMN, especially when distal stimulation has proved unhelpful.     

Clinical and neurophysiological evaluation of progression in amyotrophic lateral sclerosis

There is a need for a sensitive neurophysiological measure of disease progression in following the course of patients with amyotrophic lateral sclerosis (ALS). We studied two groups of nine ALS patients, one with slow progression (Group A) and the other with rapid progression (Group B). We evaluated muscle strength scores using the Medical Research Council (MRC) scale in limb and trunk muscles, forced vital capacity (FVC), and ALS functional rating scale (ALS-FRS) scores. Maximal voluntary isometric contraction (MVIC) of the abductor digiti minimi muscle (ADM) was measured, using a digital device. We also measured M-wave amplitude and area in the ADM, and the distal motor latency and F-wave frequency in the ulnar nerve; from these data, the neurophysiological index (NI) was calculated, as described previously. In both groups, the NI was the most sensitive measure of change, with the smallest coefficient of variation. We conclude that the NI, which requires no special technology and no new clinical or technical skills to use, is sensitive to change, and therefore may be useful in clinical trials, as well as in a clinical setting.     

肌萎缩侧索硬化患者膈神经传导的电生理分析

目的 通过分析肌萎缩侧索硬化(Amyotrophic Lateral Sclerosis,ALS)患者膈神经传导检测,并结合其它神经电生理资料,为该病提供更深入的认识,进一步指导临床诊疗。方法 研究范围为武汉大学人民医院2014年1月-2021年12月就诊的ALS患者共88例,收集患者的一般资料、主要症状及体征、肌萎缩侧索硬化改良量表(ALSFRS-R)评分、运动神经传导检测中的复合肌肉动作电位(CMAP)波幅和远端运动潜伏期(DML)等指标。结果(1)运动神经传导检测中CMAP波幅降低192条(43.6%),膈神经波幅异常率为35.2%; 远端潜伏期延长116条(26.4%),膈神经DML异常率为77.3%;(2)膈神经DML在性别方面存在明显差异(P<0.01);(3)ALSFRS-R评分与膈神经、尺神经、正中神经、腓总神经、胫神经的CMAP波幅呈正相关(r=0.393,P<0.01; r=0.375,P<0.01; r=0.413,P<0.01; r=0.251,P<0.05; r=0.442,P<0.01);(4)膈神经DML及CMAP波幅在起病部位方面存在明显差异(P<0.05; P<0.05);(5)膈神经DML在判断病情中度和轻度之间的最佳界点为9.095 ms,敏感性为85.7%,特异性为80.2%。结论 ALS患者的运动神经传导可表现异常,CMAP波幅下降占比较大,但膈神经中潜伏期延长比CMAP波幅降低更多见。膈神经传导检测存在一定程度的性别差异。行运动神经传导检测时多条神经CMAP波幅变化可反映ALS患者病情严重程度。膈神经潜伏期变化可更敏感地反映ALS的病情严重程度,以期指导临床诊断与治疗。     

Repeater F-waves in amyotrophic lateral sclerosis: Electrophysiologic indicators of upper or lower motor neuron involvement?

ObjectiveTo extract insight about the mechanism of repeater F-waves (Frep) by exploring their correlation with electrophysiologic markers of upper and lower motor neuron dysfunction in amyotrophic lateral sclerosis (ALS).MethodsThe correlations of Frep parameters with clinical scores and the results of neurophysiological index (NI), MScanfit MUNE, F/M amplitude ratio (F/M%), single and paired-pulse transcranial magnetic stimulation (TMS), and triple stimulation technique (TST) studies, recorded from abductor digiti minimi (ADM) and abductor pollicis brevis (APB) muscles of 35 patients with ALS were investigated.ResultsFrep parameters were correlated with NI and MScanfit MUNE in ADM muscle and F/M% in both muscles. None of the Frep parameters were correlated with clinical scores or TST and TMS measures. While the CMAP amplitudes were similar in the two recording muscles, there was a more pronounced decrease of F-wave persistence in APB, probably heralding the subsequent split hand phenomenon.ConclusionOur findings suggest that the presence and density of Freps are primarily related to the degree of lower motor neuron loss and show no correlation with any of the relatively extensive set of parameters for upper motor neuron dysfunction.SignificanceFreps are primarily related to lower motor neuron loss in ALS.     

F-wave latency,the most sensitive nerve conduction parameter in patients with diabetes mellitus

In this study we examined the diagnostic sensitivity of minimal F-wave latency, F-wave persistence, motor nerve conduction velocity (MCV), and amplitude of the compound motor action potential (CMAP) of the median, ulnar, tibial, and peroneal nerves, and of sensory conduction velocity (SCV) and sensory nerve action potential (SNAP) amplitude of the sural nerve in 82 diabetic patients. For the median, ulnar, and tibial nerves the Z scores of the minimal F-wave latency were significantly larger than those of the MCV, and for all four motor nerves the Z scores of the minimal F-wave latency were significantly larger than those of the amplitude of the CMAP. The Z scores of the peroneal minimal F-wave latency exceeded those of peroneal MCV, sural SCV, and sural SNAP. F-wave persistence did not differ significantly from the reference values. In conclusion, minimal F-wave latency is the most sensitive measure for detection of nerve pathology and should be considered in electrophysiological studies of diabetic patients. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20: 1296–1302, 1997     

Terminal latency abnormality in amyotrophic lateral sclerosis without split hand syndrome

Amyotrophic lateral sclerosis (ALS) has a peculiar involvement pattern; clinically it is known as split hand syndrome and electrophysiologically shows abnormalities in the abductor pollicis brevis (APB)/abductor digiti minimi (ADM) ratio. The aim of this study was to find a significant electrophysiological parameter in upper limb onset ALS patients with normal APB/ADM ratio when compared to cervical spondylotic amyotrophy (CSA) and healthy controls. We retrospectively reviewed the electrophysiological results of 47 upper limb onset ALS and 42 CSA cases; 20 healthy individuals were included as controls. We included ALS and CSA patients with normal ADM/APB ratio (≥0.6, and ≤1.7), and the parameters of electrophysiological study were compared. The electrophysiological parameters of statistical significance among ALS, CSA and normal controls were: amplitude of median and ulnar nerves, the terminal latency of median nerve, F-wave latency of median and ulnar nerves, terminal latency ratio of ulnar/median nerves, and F-wave latency ratio of ulnar/median nerves (p < 0.05). Among these parameters, the terminal latency ratio of ulnar/median nerve and terminal latency of median nerve in ALS were significantly different with both of CSA and normal control (p < 0.006). The abnormality in the terminal latency of the median nerve can be partly explained by the distal motor axonal dysfunction due to sodium and potassium channel abnormalities. The hypothesis of distal axonopathy is known to play an important role in the pathogenesis of ALS causing a significant prolongation of the terminal latency in the median nerve and the ulnar/median nerve ratio.     

Length-dependent weakness and electrophysiological signs of secondary axonal loss in chronic inflammatory demyelinating polyradiculoneuropathy

In chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) the pathophysiology underlying permanent muscle weakness and sensory loss was studied in 22 stabilized long-term CIDP patients clinically characterized using isokinetic dynamometry, quantitative sensory testing, and neuropathy scores. Conduction velocity (CV), distal latency (DLAT), minimal F-wave latency (FLAT), compound muscle action potential (CMAP), and amplitude decay between distal and proximal stimulation sites were determined in the median, ulnar, peroneal, and tibial motor nerves and sensory CV and nerve action potentials in the median and sural nerves. Amplitude of CMAP and the DLAT were related to quantitative muscle strength, whereas CV, FLAT, amplitude decay, and dispersion were not consistently related to strength. Furthermore, CMAP and muscle strength were significantly more reduced distally than proximally. In conclusion, the electrophysiological signs of axonal loss and the associated length-dependent muscle weakness suggest secondary axonal loss in addition to primary demyelination in CIDP.     

Nerve conduction study in Sydenham's chorea.

Sydenham's chorea (SC) is a late complication of group A beta-hemolytic streptococci infection presumably caused by an abnormal autoimmune reaction. Despite rare case reports of peripheral neuropathy associated with streptococcal infection, there is no investigation of peripheral nerve in SC. We performed nerve conduction studies in a cohort of patients with SC. The neurophysiology investigation comprised measurement of amplitude and sensory conduction velocity of median, ulnar, and sural nerves; amplitude and motor conduction velocity; and F-wave latency of median, ulnar, fibular, and tibial nerves. Twenty-six patients entered the study (12 females, 14 males; mean age 12.8 +/- 3.6 years). Thirteen subjects had absent or decreased deep reflexes. All investigated neurophysiological parameters fell within the normal range for our population. We failed to find neurophysiological evidence of peripheral nerve involvement in patients with a history of SC. Our findings suggest that the possible autoimmune dysfunction in SC patients is not targeted against epitopes present in peripheral nerves.     

Interrelationship among nerve conduction velocity, amplitudes of compound muscle and compound nerve action potentials in diabetic neuropathy]

In order to clarify the relationship among amplitudes of compound nerve action potential (CNAP), compound muscle action potential (CMAP) and nerve conduction velocity parameters, data of nerve conduction studies were analyzed in 102 patients with diabetes mellitus. In motor conduction studies CMAP amplitudes after stimulations at the distal nerve trunk, and the polyneuropathy index (PNI), a mean percentage of normal for 12 indices from 4 nerves concerning to the velocity or long distance latency, were evaluated. CNAP was recorded in the median and ulnar nerves from an intrafascicularly inserted microelectrode at the elbow after wrist stimulation. CMAP amplitudes were high in the median and ulnar nerves, and were reduced in the tibial and peroneal nerves. A close relationship was found between PNI and CNAP amplitudes. Among CMAP amplitude parameters tibial nerve, not median or ulnar nerves, had a good correlation with PNI and CNAP amplitude. Along with the progression of diabetic neuropathy, neuropathic signs or symptoms become conspicuous, and nerve conduction velocity drops as is expressed by the PNI level, which reflects the change in nerve conduction velocity in the upper and lower limbs. At the same time CNAP amplitude or CMAP amplitude in the tibial nerve decreases, but in nerves of the upper limb CMAP amplitude doesn't always decrease. So, tibial nerve is best among CMAP amplitude parameters in evaluating the degree of diabetic neuropathy. It is necessary to judge the degree of diabetic neuropathy after due consideration of these facts.     

Clinical value of F-wave recordings in traumatic cervical spinal cord injury

F-waves and motor/sensory nerve conduction (NCS) of the median and ulnar nerves were examined in 66 patients with traumatic motoneurone lesion due to acute and chronic cervical spinal cord injury (SCI). The examinations were performed in parallel in chronic tetraplegics once and in acute tetraplegic patients monthly for the first 3 months, after 6 months and 1 year post-trauma. A pathological reduction of the compound muscle action potential (CMAP) (in 10% even a complete loss of the CMAP) was present in about 50% of the patients. The mean CMAP values of tetraplegic patients with either acute or chronic SCI were significantly (P < 0.001) reduced compared to normal subjects. Because sensory nerve conduction in these patients was normal, the reduction of CMAP should be due to damage of intramedullar motoneurones or anterior nerve roots. While in all chronic SCI patients with preserved CMAP F-waves could be elicited, 50% of the acute SCI patients showed a complete loss of F-waves of both nerves during the initial examination due to spinal shock. After 6 months all acute SCI patients with preserved motor potentials regained F-waves. Therefore, the excitability of F-waves is influenced by spinal shock in acute SCI. The mean F-wave latencies (Fmin-response, Fmin-M response) revealed no significant difference between healthy subjects and SCI patients. However, the frequency of F-wave production was related to the severity of the motoneurone lesion. Furthermore, while the F-wave latencies and CMAP values did not change significantly with time after acute SCI, the frequency of F-wave production increased, but remained reduced compared to normal subjects.     

Comparison between Dyck's criteria and the polyneuropathy index-revised (PNI-R) in the electrophysiologic evaluation of diabetic neuropathy]

In Rochester diabetic neuropathy research by Dyck et al., abnormal value in two or more nerves was introduced into the nerve conduction criteria of diabetic neuropathy. Polyneuropathy index-revised(PNI-R) is calculated as the mean percentage of the normal of 8 parameters on the motor nerve conduction studies. They were motor nerve conduction velocities in the forearm or leg segment and F-wave latencies after wrist or ankle stimulation concerning to the median, ulnar, peroneal and posterior tibial nerves. F-wave latencies were adjusted to 160 cm height and used reciprocals in comparison with normal values. To compare these two indices, first we obtained the normal limit(1st or 99th percentile value) of each parameter from the data of 62 healthy individuals. Then in 78 patients with diabetes mellitus number of abnormal nerves and the PNI-R were investigated. Abnormal values were frequently observed in the categories of motor nerve conduction velocities and F-wave latencies. Amplitude of compound muscle action potential (CMAP) or sensory nerve action potential(SNAP) in each nerve had a large standard deviation. In such parameters abnormal rate was extremely low, because the lower limit of normal being very small. Nevertheless, sigma CMAP which means the summation of amplitudes of 3 CMAPs had as high as 53% of abnormal rate. The coefficient of correlation between number of abnormal nerves and the value of PNI-R mounted up to -0.87. Instead, the coefficient of correlation of sigma CMAP or sigma SNAP, which means the summation of amplitudes of ulnar and sural SNAPs, with PNI-R were 0.65 and 0.79, respectively. In 14 patients PNI-R was normal and the number of abnormal nerves was 0 or 1. In 59 both categories were abnormal, and only in 5 they were not coincide. As to the clinical signs PNI-R had better correlation than number of abnormal nerves with vibration threshold or degree of Achilles tendon reflex. sigma CMAP is a convenient index to detect the existence and the degree of neuropathy. This index expresses the degree of neurogenic muscular atrophy, though it doesn't always advance parallel to the decrease in number of motor nerves. sigma SNAP had higher coefficient of correlation with PNI-R or number of abnormal nerves than sigma CMAP. In conclusion, abnormal PNI-R and abnormal value in two or more nerves are both useful and coincide with each other in the detection of diabetic neuropathy. The PNI-R is an excellent quantitative index, and the PNI-R corresponds well with the number of abnormal nerves. These observations indicate that the number of nerves with abnormal value is also available as a simple and semi-quantitative index of diabetic neuropathy.     

肌萎缩侧索硬化患者神经传导分析

目的分析肌萎缩侧索硬化(ALS)患者的神经传导特点,并探讨神经传导与不同起病部位之间的关系。方法收集于2012年1月至2014年12月期间我院门诊或病房收治的ALS患者47例和体检的健康对照组40例,均测定其运动及感觉神经传导、F波。结果ALS患者运动神经传导检测表现为潜伏期(DML)延长,复合肌肉动作电位(CMAP)波幅下降,传导速度(MCV)减慢,其中以CMAP波幅下降为主。可见"分裂手"和"分裂足"现象。部分病人的症状、体征或电生理出现感觉神经受累证据。部分病人的F波出波率异常。结论诊断ALS需对临床和神经电生理进行综合分析,不能仅凭其中一项而轻易排除诊断。临床医生,特别是基层医院医生,要全面细致地完善辅助检查结果,减少漏诊和误诊的发生。     

Nerve conduction studies in amyotrophic lateral sclerosis.

Nerve conduction studies (NCS) are an integral part of the evaluation of amyotrophic lateral sclerosis (ALS) patients and are useful in distinguishing ALS from disorders that mimic it. The question often arises whether in the presence of severe atrophy and reduction of the compound muscle action potential amplitude, abnormal conduction velocity (CV), distal latency (DL), or F-wave latency (F) exceeds what can be expected from ALS alone. To determine the limits of abnormality in classic ALS, we prospectively evaluated NCS data from 61 patients who met a strict clinical definition of ALS. We related CV, DL, and F to distal evoked amplitude (AMP) in peroneal (n = 63 observations), median (n = 50), and ulnar (n = 52) nerves. In nerves with reduced AMP, CV rarely fell to less than 80% of the lower limit of normal, and DL and F rarely exceeded 1.25 times the upper limit of normal. Utilizing the entire data set and regression analyses, 95% confidence limits for expected values for CV, F, and DL as a function of AMP were calculated. These limits thus derived suggest criteria for NCS abnormalities in ALS and may be useful in differentiating ALS from other illnesses.     

Symmetry of phrenic nerve motor response in amyotrophic lateral sclerosis

To test for interside differences and ipsilateral correlation of compound muscle action potentials (CMAP) from muscles of the cervical region according to El Escorial criteria, we stimulated the phrenic, axillary, and ulnar nerves bilaterally in 67 patients with amyotrophic lateral sclerosis. The diaphragm CMAP was symmetric, but it did not correlate with deltoid or abductor digiti minimi (ADM) CMAPs. The deltoid CMAP in all groups and ADM CMAP in bulbar- and lower-limb-onset patients showed significant interside correlation. The ADM CMAP is asymmetric in upper-limb-onset patients. Unilateral stimulation is sufficient to monitor the phrenic nerve response; its degree of CMAP decrease does not correlate with other cervical muscle involvement.