Association Between Rectus Abdominis Denervation and Ventilation Dysfunction in Patients with Amyotrophic Lateral Sclerosis.

BACKGROUND: Spontaneous potentials in electromyography (EMG) of paraspinal muscles are associated with diaphragm denervation and, therefore, poor respiratory function in amyotrophic lateral sclerosis (ALS) is understandable. EMG changes in the rectus abdominis (RA) display an effect similar to those in paraspinal muscles with respect to the function of lower motor neurons in the thoracic spinal cord. The RA denervation was examined to determine its association with ventilation dysfunction in ALS. METHODS: We collected the clinical data of 128 patients with sporadic ALS in Department of Neurology of Peking University Third Hospital from 2009 to 2013. EMG, Revised ALS Functional Rating Scale (ALSFRS-R) and forced vital capacity (FVC) were performed in all patients and the differences in the EMG changes in RA between those with and without FVC ≥ 80% were analysed. RESULTS: The mean FVC value was 83.4% ± 17.1% (range: 45%-131%) of the predicted value. A total of 79 patients displayed FVC ≥80%, and 49 patients displayed FVC <80%. Compared with the patients displaying a normal FVC (60/79, 75.9%), spontaneous activity in RA was significantly different among those patients displaying an FVC <80% (47/49, 95.9%). In addition, spontaneous potentials in RA were more frequently detected in patients exhibiting dyspnea (32/33, 97.0%) than in patients without dyspnea (75/95, 78.9%). CONCLUSION: Spontaneous potentials in RA are associated with ventilation dysfunction and dyspnea in ALS patients.

[Study on chemical constituents from crop pathogenic fungus active fraction of Wisteria sinensis tumor].

OBJECTIVE: To study the chemical constituents from the crop pathogenic fungus active fraction of Wisteria sinensis tumor. METHODS: The chemical constituents were extracted of different concentrations and isolated by silica gel and Sephadex LH-20 column. The chemical structures of components were further elucidated by the physicochemical characters and MS, NMR spectral data. RESULTS: Ten compounds were isolated and identified as dibutyl phthalate (1), diacetonealcohol (2), pinoresinol (3), stellasterol (4), oleanolic acid (5), olean-12-ene-3-oxo-22,24-diol (6), betulinic acid (7), 2',4',4-hydroxy-chalcone (8), avicularin (9) and quercetin-3-O-ß-D-glucopyranoside (10). CONCLUSION: All the compounds are isolated from the genus for the first time.

[Clinical and neurophysiologic profiles of sensory neuron disease].

OBJECTIVE: To explore the clinical and electrophysiological characteristics of sensory neuron disease (SND). METHODS: The clinical and electrophysiological characteristics were analyzed from November 2007 to November 2012 in 57 patients with sensory neuron disease and another 95 with sensory polyneuropathy. Nerve conduction studies of median nerve, ulnar nerve, tibial nerve, peroneal nerve and sural nerve and electromyogram (EMG) of bulbar, cervical, thoracic and lumbosacral region, somatosensory evoked potential (SEP) and contact heat evoked potential (CHEP) were performed. RESULTS: The amplitude of sensory nerve action potential (SNAP) decreased in 50 SND patients and disappeared in another 7. The parameters of SEP and CHEP were abnormal. The amplitude of SNAP was lower in median and ulnar nerve than in sural nerve ((0.6 ± 0.2) µV, (0.7 ± 0.2) µV vs (1.5 ± 0.5) µV; t = 2.42, 2.38; P < 0.05). The latencies of SEPs were longer in SND patients than in those with sensory polyneuropathy (t = 1.99, 1.99, 2.00, 2.07, 1.99; 1.98, 1.99, 2.02, 1.98, 1.99; P < 0.05).Comparing with those with sensory polyneuropathy, the latencies of CHEP were longer in SND patients when the stimuli was applied at hand dorsum, proximal volar forearm and anticus tibialis (t = 2.01, 2.00, 2.02; P < 0.05). No difference existed in latencies between 2 groups when the stimuli was at the levels of C7 and T12 (t = 0.97, 0.68; P > 0.05). CONCLUSION: Sensory neuron diseases usually present with sensory symptoms and ataxia. The amplitude of SNAP decreases or disappears especially in upper extremities. Both SEP and CHEP are abnormal.

[Clinical and neuro electrophysiologic study of flail arm syndrome].

OBJECTIVE: To explore the clinical and neuroelectrophysiological characteristics of flail arm syndrome (FAS). METHODS: The clinical and neuroelectrophysiological characteristics were analyzed retrospectively from July 1, 2006 to July 1, 2012 in FAS patients (n = 56), those with upper limb onset amyotrophic lateral sclerosis (ALS) (n = 60) and those with upper brachial plexus neuropathy (n = 22) from our hospital. Nerve conduction study of musculocutaneous, axillary, median, ulnar, radial, tibial, peroneal and sural nerves and electromyogram (EMG) of bulbar, cervical, thoracic and lumbosacral regions were conducted. RESULTS: In FAS patients, the ratio of male-to-female was 5:1 and they were characterized by symmetric, proximal wasting and weakness of upper extremities, the involved muscles demonstrated neurogenic damage on EMG and the amplitude of compound muscle action potential (CMAP) of arms decreased. Compared with ALS patients, the amplitude of motor unit action potential (MUAP) of deltoid muscle and biceps muscle was higher in FAS patients ((1531 ± 76) vs (898 ± 57) µV; (1433 ± 57) vs (872 ± 75) µV) (F = 13.25, 6.33; P < 0.05). Compared with upper brachial plexus neuropathy patients, the amplitude of MUAP of first dorsal interosseous, deltoid and biceps muscles was higher in FAS patients ((1263 ± 24) vs (507 ± 42) µV; (1531 ± 76) vs (564 ± 27) µV; (1433 ± 57) vs (593 ± 36) µV) (F = 12.32, 16.71, 8.35; P < 0.05). CONCLUSION: The clinical manifestations of FAS are symmetric, proximal wasting and weakness of arms. And the involved muscles show denervation on EMG and the amplitudes of CMAPs decrease in motor nerves of upper extremities.

[Phenolic derivatives from Wisteria sinensis sweet caulis].

OBJECTIVE: To study the phenolic derivatives from Wisteria sinensis. METHODS: From the petroleum ether extraction of 95% alcohol permeating extraction, 12 compounds were isolated and purified with silica gel and Sephadex LH-20 column chromatography. Their structures were determined on the basis of physicochemical properties and spectroscopic analysis. RESULTS: They were identified as formononetin (1), (3S)-vestitol (2), (6aS, 11aS)-medicarpin (3), (-+/-) isoduartin (4), (3S)-7,1'-dihydroxy-8,3'-dimethoxyisoflavan (5), isosakuranetin (6), p-hydroxy-benzaldehyde (7), 11b-hydroxy-11b, 1-dihydromedicarpin (8), 3-hydroxy-medicarpin (9), syringaresinol (10), 5-hydroxy-7-methoxychromone (11), vanillin (12). CONCLUSION: All the compounds are isolated from this plant for the first time.

[Target points: a discussion on acupuncture treatment of primary trigeminal neuralgia].

In this paper, issues of acupuncture using target points and depth of needling were discussed based on the theory of traditional Chinese medicine acupoints and combined with anatomical and neurological research of Western medicine. The theoretical evidence of acupuncture on nerve foramen and ganglion and the reasons for being nonstandard operating on acupoints were analyzed. This study summarized the method of using acupuncture at Xiaguan (ST7), Cuanzhu (BL2), Sibai (ST2) and Jiachengjiang acupoints to align with the spheno-palatine ganglion and additional nerve foramen (supraorbital, infraorbital and mental foramina) to treat primary trigeminal neuralgia. This study adhered to the Standards for Reporting Interventions in Clinical Trials of Acupuncture and helped in development of study standardization for acupuncture processes. The authors hoped that should help in significantly diminishing risk and improving therapeutic efficacy in clinic.

[A study of motor unit number estimation by multiple point stimulation in patients with Hirayama disease].

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 228.31 ± 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 (χ(2) = 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 (χ(2) = 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.

[Diagnostic role of triple stimulation technique in patients with multifocal motor neuropathy].

OBJECTIVE: To detect the conduction block (CB) between nerve root and Erb's point by triple stimulation technique (TST) in patients with multifocal motor neuropathy (MMN). METHODS: The subjects were recruited from Peking University Third Hospital during the period of April 2010 to April 2011. Twelve MMN patients, 30 healthy subjects, 30 patients with cubital tunnel syndrome and 30 patients with amyotrophic lateral sclerosis (ALS) underwent TST along with clinical assessments and nerve conduction studies. TST combined transcranial magnetic stimulation (TMS) of motor cortex with peripheral collision studies. The results were expressed by the TST amplitude ratio. And the conduction block was judged by TST amplitude ratio or the amplitude ratio of compound muscle action potential (CMAP). RESULTS: The TST amplitude ratio of healthy volunteers was 93.0% ± 2.7%. And it was 42.3% ± 7.1% in patients with MMN indicating a proximal CB. There were 47 CBs in distal segments by routine nerve conduction study. Compared with the baseline levels, the patients with definite MMN increased (χ(2) = 6.31, P < 0.05). The TST amplitude ratio (30.5% ± 4.8%) of those with ALS indicated the lesion of pyramid tract (t = 2.43, P < 0.05). And the TST amplitude ratio (92.2% ± 2.6%) of those with cubital tunnel syndrome was normal (t = 0.68, P > 0.05) while the nerve conduction velocity of cubital tunnel syndrome patients (below elbow-above elbow) was slower ((23.6 ± 3.5) m/s) (t = 2.00, P < 0.05). CONCLUSION: TST may be used to detect proximal CB and facilitate the diagnosis of MMN.

[Study on triterpenoids from Wisteria sinensis].

OBJECTIVE: To study the triterpenoids constituents from Wisteria sinensis Sweet Caulis. METHODS: The compounds were beta-solated and purified with silica gel and Sephadex LH-20 column chromatography from the petroleum ether extract. Their structures were determined on the basis of physicochemical properties and spectroscopic analysis. RESULTS: They were identified as beta-sitosterol palmitate (1), alpha-spinasterol (2), (22E, 24R)-5alpha, 8alpha-epidioxy-ergosta-6, 22-dien-3beta-ol (3), (22E, 24R)-ergosta-5, 7, 22-trien-3beta-ol (4), (22E, 24R) -ergosta-7, 22-dien-3beta-ol (5), 11alpha, 12alpha-oxidotaraxerol (6), lupeol (7), betulinic acid (8), 22-oxo-3beta, 24-dihydroxyolean-12-ene (9), 2alpha, 3beta, 23-trihydroxyolean-12-ene (10), soyasapogenol E (11), 3alpha, 21beta-dihydroxy-olean-12-ene (12). CONCLUSION: Compounds 1 - 12 are isolated from this plant for the first time.

Upper trapezius electromyography aids in the early diagnosis of bulbar involvement in amyotrophic lateral sclerosis.

Electromyography (EMG), particularly measurements of the tongue or sternocleidomastoid, aids in the diagnosis of amyotrophic lateral sclerosis (ALS) and may be used to identify lower motor neuron lesions in the bulbar region. Abnormal trapezius EMG recordings were recently shown to be useful in diagnosing ALS. Here, we investigated the role of upper trapezius EMG in assessing bulbar involvement in ALS. Standard EMG measurements were recorded from the upper trapezius in ALS, cervical spondylotic myelopathy (CSM), and normal controls (NC). Forty-three CSM patients were examined pre-operatively and three months post-operatively. Greater spontaneous activity levels were observed in upper trapezius EMG measurements of ALS patients with a disease duration of ≤8 months (70%), compared with patients with a disease duration of >8 months (40%). Significant differences in motor unit action potential parameters were also noted between ALS and CSM or NC. Fewer spontaneous EMG recordings were detected in CSM post-operatively. Furthermore, no differences in neurogenic EMG measurements were observed in ALS between the trapezius and sternocleidomastoid muscles (p = 0.22). In conclusion, upper trapezius EMG recordings may provide valuable information for assessing the clinical and subclinical involvement of bulbar lower motor neurons in ALS patients, particularly at early disease stages.

[Role of fasciculation potentials in the diagnosis of amyotrophic lateral sclerosis].

OBJECTIVE: To explore the role of fasciculation potentials in the diagnosis of amyotrophic lateral sclerosis (ALS). METHODS: A total of 60 ALS patients were recruited from August 2009 to August 2010 at our hospital. Standard examinations of electromyography and nerve conduction were performed. And fasciculation potentials were measured in the resting muscles with a band pass of 20 Hz-10 kHz, a sensitivity of 0.05 - 0.5 mV/D and a sweep speed of 5 ms/D. Each muscle was observed for 1 - 5 minutes. The amplitude, duration and phase of fasciculation potentials were recorded. RESULTS: The occurrence rate of fasciculation potential in sternocleidomastoid was more than that of fibrillation and positive sharp wave in ALS patients (36.7% vs 13.3%, χ² = 8.71, P < 0.05). The amplitude and duration of fasciculation potentials in ALS patients with a duration of over 18 months were higher than that of those with a duration of under 8 months [(1.8 ± 0.9) mV, (1.0 ± 0.6) mV; (15.2 ± 4.1) ms, (11.2 ± 3.0) ms; q = 3.43, 3.51, P < 0.05)]. The patients with definite ALS might increase if fasciculation potentials were considered as spontaneous potential (80% vs 60%; χ² = 5.71, P = 0.02). CONCLUSION: With different morphologies at different disease stages, fasciculation potentials may be useful in the earlier diagnosis of amyotrophic lateral sclerosis.

[Basic and clinical researches on amyotrophic lateral sclerosis/motor neuron disease].

This study includes three aspects: (1) we have reported some novel or rare mutations of SOD1 (Cu/Zn superoxide dismutase) gene in Chinese families of ALS/MND, and found quite different features from Western patients in polymorphisms with some candidate genes such as vascular endothelial growth factor (VEGF) in sporadic ALS/MND in China. Meanwhile, we have so for established a complete clinical database with more than 1 200 cases; (2) we have established some neurophysiologic techniques of diagnosis and differential diagnosis at early-stage for ALS/MND, which include trigemino-cervical response, sternocleidomastoid and rectus electromyography, contact heat evoked potentials, and motor unit number estimate; (3) we have attempted some experimental and clinical treatments for ALS/MND, which include gene and stem cell therapies in animal models, and a pilot clinical trial of granulocyte colony stimulating factor (G-CSF) for ALS/MND patients (NCT00397423).

Fully intact contact heat evoked potentials in patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is typically considered to be a disease of motor, not sensory, neurons. However, reports exist of sensory system involvement in ALS. In this study we aimed to study the characteristic of contact heat-evoked potentials (CHEPs) in patients with ALS and to evaluate the nociceptive pathway in these patients. Sixty patients with ALS and 60 controls had pain elicited by a CHEP stimulator with an accelerated velocity of 70 degrees C/s. Thermal stimuli were sent at 54.5 degrees C to three body sites: the dorsum of the hand, the proximal volar forearm, and the skin near C7. CHEPs were recorded from Cz and Pz. The onset negative peak latencies were 561.2 +/- 28.6 ms, 540.1 +/- 39.2 ms, and 502.4 +/- 26.2 ms when the dorsum of the hand, the proximal volar forearm, and skin near C7 were stimulated, respectively. There were no significant differences between the ALS patients and the controls with CHEP (P > 0.05). Our results suggest that the nociceptive pathway is intact and support the idea that small fibers and their sensory pathway are spared in ALS.

Stratifying disease stages with different progression rates determined by electrophysiological tests in patients with amyotrophic lateral sclerosis.

By determining the usefulness of motor unit number estimate (MUNE) and compound muscle action potential (CMAP) amplitude in patients with amyotrophic lateral sclerosis (ALS), we tried to find an effective way to stratify the disease stages. In all, 112 consecutive ALS patients were enrolled, among whom 73 were elicited in a longitudinal study. MUNE by the standard incremental technique, the average CMAP amplitude, total Medical Research Council (MRC) score, ALS-functional rating score (ALS-FRS), Appel ALS rating scale (AARS), and forced vital capacity (FVC) were performed at baseline and months 3, 6, and 12 after study entry. We found MUNE correlated with CMAP amplitude (P < 0.01) as well as MRC score (P < 0.01) in regionally concordant distal muscles. Both MUNE and CMAP amplitude correlated significantly with ALS-FRS (P < 0.05) and AARS (P < 0.01). A MUNE decrease was observed at months 3, 6, and 12 compared with baseline, and the rate of change at month 3 was 50.47%. The decrease in MUNE over the first 3 months was significantly greater than other measurements. We arbitrarily divided the patients into three stages: (1) rapid progression: the rate of change of MUNE and CMAP amplitude during the first 3 months exceeded 50%; (2) moderate progression: the rate of change of MUNE was greater than 50% but CMAP amplitude was less than 50%; (3) slow progression: the rate of change of both MUNE and CMAP amplitude were less than 50%. Comparing the rate of ALS-FRS descent per year using one-way ANOVA showed a significant difference among the three groups (P < 0.01).

[Comparison of multiple point stimulation and incremental stimulation in patients with amyotrophic lateral sclerosis].

OBJECTIVE: To compare two common techniques for motor unit number estimation (MUNE), multiple point stimulation and incremental stimulation to determine which is preferable in patients with amyotrophic lateral sclerosis (ALS). METHODS: Surface recorded motor unit action potentials of median nerve or thenar muscle were measured in 60 ALS patients and 60 controls. 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 wrist, 6 cm above the wrist, elbow and 6 cm above the elbow. Individual motor unit responses were obtained by moving the stimulating electrode and isolating threshold responses with distinct morphologies. Then, with finely graded stimulus intensity at one point, 3 steps in a CMAP were investigated. 10 - 12 different single motor unit action potentials (SMUPs) were recorded. For incremental stimulation, stimulus intensity was slowly increased 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. Individual motor unit amplitudes were obtained by subtracting amplitudes of each response from that of prior response. Both techniques were performed twice, electrodes changed and results averaged. RESULTS: For controls, MUNE was 228 +/- 30 for multiple point stimulation and 198 +/- 26 for incremental stimulation. Test-retest correlation coefficients and coefficients of variation for mean of two MUNE were 0.88 - 0.91 and 13.20% - 15.24% for multiple point stimulation, 0.86 and 13.30% - 15.65% for incremental stimulation. For ALS patients, MUNE was 64 +/- 6 and 59 +/- 7 respectively. CONCLUSION: Both MUNE methods are similarly reproducible and are equally effective at documenting progression of a lower motor neuron disorder in ALS patients.

[The electromyography of rectus abdominis muscle in the diagnosis of polyneuropathy].

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) microV was higher than that of the controls (373.78 +/- 56.46)microV(t = 2.01, P < 0.04) and lower than that of patients with ALS (537.19 +/- 159.04) microV (t = 2.32, P < 0.03). CONCLUSION: EMG of rectus abdominis muscle might be used to find the lesion of intercostal nerve in polyneuropathy.

[Follow-up study of patients with chronic motor axonal neuropathy].

OBJECTIVE: To study the characteristic of chronic motor axonal neuropathy and the prognosis of it. METHODS: 16 chronic motor axonal neuropathy (CMAN) patients were diagnosed by clinical manifestation and neurophysiologic manifestation. Follow-up study was done including living state, medicine they taken, change of physical sign and motor unit number estimation. 60 patients with amyotrophic lateral sclerosis were studies at the same time. The prognosis of these patients was compared. RESULTS: After being treated with intravenous immunoglobulin therapy, the patients with CMAN showed a good clinical recovery except 6 patients who had the characteristic of ALS in the 18 months follow-up study, and the MUNE changed from 68 +/- 17 to 154 +/- 25. On the contrary, the patients with ALS had worse clinical manifestation, and the MUNE changed from 64 +/- 6 to 55 +/- 9. CONCLUSIONS: Immunological factor may be involved in the mechanism of chronic motor axonal neuropathy which has a better prognosis and is difficult to differentiate from amyotrophic lateral sclerosis in the earlier stage.

[Test of sensory nerve in patients with Kennedy disease].

OBJECTIVE: To study the electrophysiological and pathological features of Kennedy disease (KD) and to make sure the functional and anatomical change of the sensory nerve of KD patients. METHODS: Electrophysiological and pathological tests were performed in 14 KD patients, including electromyogram, conduction velocities of median, ulnar, peroneal, tibial, and sural nerves, trigemino-cervical reflex (TCR), contact heat evoked potential (CHEP), and biopsy of the sural nerves. During TCR, the patients lay on the back, holding the heads slightly raised to make the sternocleidomastoid muscles contract slightly. Electrical stimuli were applied to the infraorbital nerves and recording electrodes were placed in the sternocleidomastoid muscles. For CHEP, contact heat was delivered via a circular thermode to excite selectively nociceptors with a rapid rising time at 70 degrees C/s to elicit pain and CHEP. Thermal stimuli were sent at 54.5 degrees C to three body sites: skin of back of hand, proximal volar forearm, and C7. The CHEPs were recorded from Cz and Pz. RESULTS: The sensory conduction velocity and latency were almost normal, while the amplitude of the sensory nerve action potential (SNAP) declined to 0.65 - 2.85 microV. The latency of trigemino-cervical reflex was longer than normal with the onset peak latency of (38.9 +/- 7.0) ms. The configuration was asymmetric. The onset peak latencies when the skin of the back of hand, volar surface of forearm, and C7 were stimulated were (613 +/- 57), (595 +/- 32), and (489 +/- 37) ms respectively. Biopsy of the sural nerves showed that the large myelinated nerve fiber was decreased. CONCLUSION: Sensory nerve is involved in the patients with Kennedy disease, including the large and small fibers.

[Establishment of a method of contact heat evoked potential and its application in carpal tunnel syndrome].

OBJECTIVE: To establish a method to evoke cerebral potentials by stimulating nociceptive fibers, estimate the conduction velocities of nerve fibers mediating these responses, and assess the value of the potentials in carpal tunnel syndrome. METHODS: One hundred patients with carpal tunnel syndrome and 20 sex-, and aged-matched healthy persons underwent stimulation of contact heat delivered via a circular thermode to excite selectively nociceptors with a rapid rising time at 70 degrees C/s to elicit pain and contact heat evoked potential (CHEP). Thermal stimuli were sent at two intensity levels (49.5 degrees C and 54.5 degrees C) to three body sites: thenar eminence, dorsum of hand, and proximal volar forearm The CHEPs were recorded from Cz and Pz. The relation between the stimulus intensity and pain rating was observed, and the main components of the evoked potential were recorded. The nerve conduction velocity was calculated from the latency difference of the CHEP and center to center distance of distal and proximal stimulus arrays. RESULTS: The pain intensity ratings were 3.2 +/- 0.3 and 4.4 +/- 0.5 when the thenar eminence was stimulated at the temperature of 49.5 degrees C and 54.5 degrees C respectively; and the ratings were 6.3 +/- 0.8 and 7.2 +/- 0.5 on the dorsum of hand and proximal volar forearm at the temperature of 54.5 degrees C respectively. Three components, Cz/N550, Cz/P750, and Pz/P1000, were found in the evoked potentials. The latency of the CHEP was significantly correlated with the arm length, and not significantly correlated with sex, age, and side difference of the arm. The conduction velocities of the Adelta and C fibers of the carpal tunnel syndrome patients were 12.0 m/s +/- 5.6 m/s and 0.6 m/s +/- 0.1 m/s respectively, both lowered, being 93.8% and 99.5% of those of the healthy persons (12.9 m/s +/- 7.5 m/s and 1.7 m/s +/- 0.4m/s respectively). CONCLUSION: Elicited reliably, CHEP is mediated by Adelta and C fibers. The conduction velocity of C fibers in the patients with carpal tunnel syndrome is decreased.