Objective To explore the significance of motor unit number estimation (MUNE) by using multiple point stimulating technique to evaluate patients with Hirayama disease (HD).Methods Multiple point stimulating technique was used to estimate the motor unit number of abductor pollicis brevis and abductor digiti minimi in 35 normal subjects [14-33 years old,mean (20.9 ±4.0) years old,33 men and 2 women]without nerve and muscle disease and 69 patients definitely diagnosed as HD [16-35 years old,mean (21.46 ±6.61 ) years old,67 men and 2 women].The differences between the two groups were examined by Fisher's exact test and t test.Results There were 42 patients with atrophy and 27 patients with normal clinical manifestation of left hand.For right hand there were 54 patients with atrophy and 15 normal.For controls,the MUNE value of left abductor pollicis brevis was 226.97 ± 30.59,while that of right side was 22g.31 ± 25.35.The MUNE value of left abductor digiti minimi was 237.43 ± 30.78,while that of right side was 240.20 ± 37.73.For HD patients,the MUNE of left abductor pollicis brevis and abductor digiti minimi was 145.66 ± 126.10 ( t =5.07,P ＜ 0.01 ) and 102.20 ± 112.67 ( t =9.31,P ＜ 0.01 )respectively,while those of right hand was 149.72 ± 117.80 ( t =5.31,P ＜ 0.01 ) and 64.23 ± 69.27 ( t =16.76,P ＜0.01 ) respectively.MUNE of left abductor digiti minimi in 17 patients that was below 200 among 27 patients with normal clinical manifestation (x2 =9.57,P =0.002).MUNE of right abductor digiti minimi in 12 patients that was below 200 among 15 patients with normal clinical manifestation ( x2 =4.64,P =0.03).Conclusions The differences of MUNE values by multiple point stimulating technique between the normal subjects and the HD patients is significant,which suggests this method is very useful to evaluate HD in the early state.

Objective To validate the technique and to establish the reference values of triple stimulation technique(TST)in healthy Chinese adults.Methods One hundred healthy subjects were recruited to undergo TST from April 2010 to February 2011 in both abductor digiti minimi.The TST combines transcranial magnetic stimulation(TMS)of the motor cortex with peripheral collision studies.Three stimuli were given,leading to two collisions.A first magnetic stimulus was applied to the scalp overlying the motor cortex.After a delay,an electric stimulus was applied over the ulnar nerve at the wrist.The delay was chosen so that the action potentials descending from the cortex collided with the antidromic action potentials evoked at the wrist,with the collision site at the wrist and above.After another delay,another electrical stimulus was applied to Erb' s point.This delay was chosen so that ascending antidromic action potentials evoked by wrist stimulation collided at or distal to Erb' s point.At the same time,TST test curves were recorded.The TST test curve was compared with a TST control curve in which the first stimulus was applied to Erb' s point and the other two stimulus sites were the same as the test curve.Control stimuli were thus applied successively to Erb' s point,the wrist,Erb' s point.TST quantifies the number of conducting central motor neurons(expressed by the TST amplitude ratio).The values were compared among genders,age groups,arm length and sides respectively.Results The TST amplitude ratio(TSTteat/TSTcontrol)was 85.0％ ± 6.7％.There were no difference among genders,age groups,arm length and sides respectively.The TST amplitude ratio were 85.0％ ± 2.6％ and 85.0％ ± 8.7％,respectively in subjects with arm length 61-70 cm and 71-80 cm.Conclusion TST could be examined precisely and the normative value could be got.

Objective To assess the normative value of motor unit action potential of trapezius electromyography(EMG)and the amplitude of compound muscle action potential(CMAP)of accessory nerve.Methods Standard EMG and CMAP of accessory nerve were recorded from upper trapezius muscle in 100 healthy volunteers.For accessory nerve,it was stimulated in the upper sternocleidomastoid muscle and was recorded in the junction of the neck and shoulder.For trapezius EMG,it was recorded also in the junction of the neck and shoulder,includiag spontaneous activity,motor unit action potential and recruitment pattern.Results The amplitude,duration,polyphasic wave of motor unit action potential was(610.7±79.2)μV,(11.2±1.5)ms,(11.7±1.2)% respectively.The amplitude of compound muscle action potential of accessory nerve was(8.7±2.3)mV.Conclusion The electromyography of trapezius and CMAP of accessory nerve can be examined accurately.

Objective To compare two common techniques for motor unit number estimation (MUNE), multiple point stimulation(MPS) and incremental stimulation, and determine which is preferable in the follow-up study of patients with amyotrophic lateral sclerosis (ALS).Methods MPS or incremental stimulation MUNE was recorded respectively in 120 ALS patients at baseline and month 3, 6, 9 ,and 12 after study entry.The maximal baseline to negative peak compound muscle action potential (CMAP) amplitude was recorded.For multiple point stimulation, the stimuli sites included the skin of the wrist, 6 cm above the wrist, elbow and 6 cm above the elbow.Individual motor unit responses were obtained by moving thestimulating electrode and isolating threshold responses.Then, with finely graded stimulus intensity at one point, 3 steps in a CMAP were investigated.For incremental stimulation, stimulus intensity was slowlyincreased from subthreshold levels until a small, all-or-none response was evoked.The intensity was slowly increased until the response increased in a quantal fashion.This process was repeated for a total of 10 increments.Single motor unit potential were obtained by subtracting amplitudes of each response from that of the prior response.The values obtained from two methods were compared.Results The value of MUNE declined in the follow-up period.MUNE obtained from MPS was the same as that gained from incremental stimulation at the baseline and the 3rd, 9th, 12th month after study entry, while MUNE obtained in MPS was more than that obtained from incremental stimulation at the 6th month after study entry ( 88 ± 6 and 47 ± 5;t = 1.72, P = 0.04).Conclusions Both MPS and incremental stimulation are certain in the follow-up study of patients with amyotrophic lateral sclerosis.The value of MUNE obtained from two methods might be different in some period.

Objective To examine the technique of multiple point stimulation for motor unit number estimation (MUNE) and to establish the normative value range in Chinese.Methods Surface-recorded motor unit action potentials were measured in 80 healthy subjects.The compound muscle action potential (CMAP) amplitude measured by maximum baseline to negative peak was recorded.The stimuli sites included the wrist, 6 cm above the wrist, elbow and 6 cm above the elbow along median nerve and ulnar nerve.Individual motor unit responses were obtained by adjusting location of the stimulate electrode and isolating threshold responses with distinct morphologies.Then, stimulus intensity was increased gradually to detect single motor unit action potentials (SMUPs).SMUPs were recorded three times.Stimulating was increase again to record another SMUPs set.Total of 12 SMUPs were recorded.Repeat the whole procedure for two times.Results MUNE was 230.0±35.7 in abductor pollieis brevis muscle, and 242.5±30.2 in aductor digiti minimi muscle for multiple point stimulation.Test-retest correlation coefficients and coefficients of variation for mean of two MUNE were 0.88-0.91 and 13.20%-15.24%.Conclusions The multiple point stimulation is a useful and replicable method to asses the MUNE.

Objective To evaluate the application of upper trapezins muscle electromyography (EMG) in the diagnosis of lower motor neuron damage in bulbar region in amyotrophic lateral sclerosis (ALS). Methods Standard EMG was recorded over upper trapezius muscle in 100 patients with ALS, 80 patients with cervical spondylotic myelopathy (CSM) and 100 normal controls. In groups of ALS and CSM,EMG was also recorded over sternocleidomastoid, rectus abdominis, first dorsal intercostals muscle and tibialis anterior muscles. Among those CSM patients, 43 patients had operations and the EMG on their trapezius muscle was examined at pre-operation and at 3 months post-operation. The parameters of EMG were analyzed between the groups. Results In ALS patients, spontaneous activity in upper trapezius EMG was detected more frequently in patients with disease duration equal to or less than 8 months than the others (21/30(70%) vs 28/70(40%), X~2=7.56, P=0.004). There was no difference in neurogenic EMG changes including abnormal spontaneous potentials and motor unit action petentials (MUAP) between trapezius and sternocleidomastoid in patients with ALS. Significant differences in MUAP were noted between ALS patients((1086.9±152.6)μV, (17.2±6.5) ms,23.6%±3.4%) and controls ((606.7± 82.7)μV,(11.6±1.8) ms,12. 8%±2.2%;q=9.27, 4.57, 4.12, all P<0.01), and between patients with ALS and patients with CSM ((615.7±90.3) μV,(12.1±2.0) ms,13.5%±2.4%,q=8.32,4. 25, 4. 23, all P < 0. 01). Few spontaneous activities in trapezius EMG were detected in post-operation CSM patients. Conclusion EMG in upper trapezius can assist in assessment of clinical and subclinical involvement of bulbar lower motor neurons in patients with ALS, especially at earlier stage.

Objective To assess the value of electromyography (EMG) of rectus abdominis muscle in the diagnosis of polyneuropathy. Methods 109 patients with polyneuropathy were studied. The routine nerve conduction study was done and standard EMG was recorded from rectus abdominis muscle, first dorsal interosseous muscle and tibialis anterior muscle. The parameters studied included spontaneous activity fibrillation potentials (fib) and positive sharp waves (psw); duration, amplitude and percentage of polyphasic wave of motor unit action potential (MUAP) and pattern of recruitment. A group of controls and patients with amyotrophic lateral sclerosis (ALS) were studied at the same time. EMG parameters of rectus abdominis muscles were compared among patients with polyneuropathy, patients with ALS and the controls.Results EMG of rectus abdominis muscle in the patients with polyneuropathy showed neurogenic change.The amplitude of motor unit potential in patients with polyneuropathy(451.67±75.01)μV was higher than that of the controls (373.78±56.46)μV (t=2. 01, P < 0. 04) and lower than that of patients with ALS (537.19±159. 04)μV (t=2. 32, P<0.03). Conclusion EMG of rectus abdominis muscle might be used to find the lesion of intercostal nerve in polyneuropathy.

Objective To study changes of trigemino-cervical reflex (TCR) in patients with Kennedy's disease (KD). Methods The parameters of TCR were analyzed among patients with KD, amyotrophic lateral sclerosis and healthy controls. Results The parameters of ipsilateral P19, N31, A and contralateral P19, N31, A among patients with KD were (23.91±4.84), (35.45±4.76) ms, 1.24± 0.33 and (24.34±4.82), (36.20±4.91) ms, 1.19±0.25, respectively. Compared with the healthy controls((18.37±2.16), (28.50±1.56) ms, 1.90±0.43; (18. 72±2. 18), (29. 19±1.43) ms, 1.84 ± 0. 40), the difference in each parameter was significant (ipsilateral : t = 5.77, 8. 19, -6. 64; contralateral:5.05, 7.62, -7.77, all P<0.01). Conclusion The parameters of TCR were abnormal in KD patients, indicating that the trigeminal nerves and the bulbar may be involved in the disease.

Objective: To establish normative value of multiple segments motor nerve conduction of bilateral median nerve and ulnar nerve, including motor nerve conduction velocity (MCV)、latency (LAT)and amplitude (AMP). Method: Two hundred normal volunteers were divided into 5 groups according to different ages. Median nerve was examined at multiple points: palm, wrist, elbow, axilla and Erb's. Ulnar nerve was examined at multiple points: wrist, below elbow, above elbow, axilla and Erb's. The values of segmental MCV, LAT and AMP were recorded. Result: Gender and sidedness had no effect on MCV, LAT and AMP of median nerve and ulnar nerve. However, age had significant effects on MCV, LAT and AMP of median nerve and AMP of ulnar nerve. Conclusion: The examination of multiple segments motor nerve conduction of bilateral median nerve and ulnar nerve possess important value in diagnosis.

Objective To study the features of pain evoked potentials in patients with amyotrophic lateral sclemsis(ALS)and evaluate the pain pathway in these patients.Methods Sixty patients with ALS and 60 controls were set on supine position.The contact heat evoked potential stimulator with a diameter of 27 mm and an area of 573 mm2was used to elicit pain and contact heat evoked potentials(CHEP)in an accelerating speed of 70 ℃/s.Thermal stimuli were given at 54.5 ℃ to three body sites:the dorsum of hand,proximal volar for aml and C7. CHEP was recorded at spots of Cz and Pz.The features of CHEP was observed At the same time,somatosensory evoked potential(SEP)was assesed.Results The figure and latency of CHEP in ALS patients were normal.The latency was:the dorsum of hand:(561.2±28.6)ms; proximal volar forarm:(540.1±39.2)ms;C7:(512.7±31.4)ms.There were no significant differences of latency and SEP between tlle ALS patients and the controls((558.7±30.2),(536.6±23.5), (501.8±26.0)ms,t=4.23,4.51,3.74,P＞0.05).Conclusion Patients with ALS have a normal CHEP,suggesting that the pain pathway in patient with ALS is intact.