Effect of laser versus placebo in tennis elbow

The purposes of this study were to compare the pain alleviating effects of laser treatment and placebo in tennis elbow. Also, the effects of laser radiation on the radial sensory nerve conduction, and the temperature changes in the tissue surrounding the treated radial nerve were studied. The results show that laser treatment is not significantly better than placebo in treating tennis elbow. Furthermore, no significant change was noted in the evoked sensory potential as well as subcutaneous temperatures in either experimental or control groups as a result of the applications of the laser radiation treatment.     

Wheelchair pushrim kinetics: body weight and median nerve function.

OBJECTIVES: Individuals who use manual wheelchairs are at high risk for median nerve injury and subsequent carpal tunnel syndrome (CTS). To gain a better understanding of the mechanism behind CTS in manual wheelchair users, this study examined the relation between (1) pushrim biomechanics and function of the median nerve, (2) pushrim biomechanics and subject characteristics, and (3) median nerve function and subject characteristics. DESIGN: Case series. SETTING: Biomechanics laboratory and an electromyography laboratory. PARTICIPANTS: Thirty-four randomly recruited individuals with paraplegia who use a manual wheelchair for mobility. INTERVENTION: Subjects propelled their own wheelchair on a dynamometer at 0.9m/sec and 1.8m/sec. Bilateral biomechanical data were obtained using a force- and moment-sensing pushrim and a motion analysis system. Bilateral nerve conduction studies focusing on the median nerve were also completed. MAIN OUTCOME MEASURES: Pearson's correlation coefficients between subject characteristics, median nerve conduction studies, and propulsion biomechanics; a regression model of nerve conduction studies incorporating subject characteristics and pushrim biomechanics. RESULTS: Subject weight was significantly related to median nerve latency (r = .36, p = .03) and median sensory amplitude (r = -.43, p = .01). Height was also significantly related to median sensory amplitude (r = -.58, p = .01). Subject weight was significantly related to the peak resultant force applied to the pushrim (r = .59, p < .001). Height, weight, and weight-normalized pushrim forces were successfully incorporated into a linear regression model predicting median sensory amplitude (r = .63, p < .05) and mean median latency (r = .54, p < .05). CONCLUSION: This study found subject weight to be related to pushrim forces and median nerve function. Independent of subject weight, pushrim biomechanics were also related to median nerve function. Through weight loss and changes in pushrim biomechanics, it may be possible to prevent median nerve injury in manual wheelchair users.     

Electrophysiologic responses of human sural nerve to temperature

The purpose of this study was to assess the conduction, specifically the latency and amplitude of the sensory nerve action potential (SNAP), of the sural nerve as a function of intraneural temperature of the leg. The electrophysiologic responses of the sural nerve were determined at different temperatures in 22 healthy adults. Distal sensory latency and amplitude of the sural SNAP was determined at 1 degree C intervals over a limb temperature range of 23 degrees to 40 degrees C. Limb temperature was monitored with a thermistor probe placed subcutaneously near the sural nerve. Ice bath soaks were used for cooling and infrared radiation for warming the limbs. An analysis of covariance was performed for the SNAP latencies and amplitudes to determine the effect of gender and leg (right or left) at each temperature level. No effect of gender or leg on neural conduction was detected in individual subjects. A regression analysis was then used on pooled data to determine the effect of temperature on sural SNAP latency and amplitude. An inverse linear change in the latency of sural SNAP was observed over the temperature ranges used. Mean latency increased 0.1 msec per 1 degree C increase in subcutaneous temperature. A direct relationship between amplitude of the SNAP and temperature was determined. Mean amplitude increased 0.3 muV per 1 degree C increase in subcutaneous temperature. The results of this study support previous reports, which state that SNAP latency is indirectly related to the intraneural temperature. Clinical electromyographers must monitor the temperature of the lower leg and foot whenever sensorineural conduction of the lower limbs is performed.     

Saphenous nerve conduction in healthy subjects

Saphenous nerve conduction was studied in 40 healthy subjects utilizing a slight modification of the method described by Wainapel et al. The mean values obtained were as follows: distal sensory latency, 2.9 +/- 0.3 msec for 10 cm distance; conduction velocity, 46.6 +/- 3.5 m/sec; and amplitude of sensory nerve action potential, 10.7 +/- 4.3 microV. The technique should be useful in the electrodiagnostic differentiation between lumbar root (L3, L4) lesions and postganglionic lesions such as lumbar plexus and femoral nerve lesions and entrapment neuropathy of the saphenous nerve.     

Compound nerve action potentials from the median and ulnar nerves

The compound nerve action potentials from mixed motor/sensory (MNAP) and sensory (SNAP) nerve stimulation in the median and ulnar nerves were recorded in both arms of 20 able-bodied subjects. Intranerve and internerve peak-to-peak amplitudes were compared. An SNAP/MNAP amplitude ratio greater than 0.25 exceeded the mean by 2SD. The fastest, intermediate, and slowest conduction velocities were calculated from chosen points on the biphasic waveform. An intermediate MNAP conduction velocity for the median and ulnar nerves of less than 49.5m/sec exceeded more than 2SD below the mean. Likewise, an intermediate SNAP conduction velocity of less than 45.5m/sec exceeded 2SD below the mean. Median MNAP latency across the carpal tunnel was 1.0 +/- 0.3 and ulnar MNAP conduction velocity across the elbow was 59.7 +/- 3.8m/sec. This technique may supplement traditional electrodiagnostic studies in evaluating upper extremity neuropathies.     

Ultrasound: evaluation of its mechanical and thermal effects

Despite the frequent clinical use of ultrasound (US), neither its effect on nerve conduction nor the explanation for these changes have been agreed upon. This study differentiated between the thermal and mechanical effects of US by using continuous US to provide combined mechanical and heating effects, pulsed US to provide an equivalent mechanical effect, placebo US to duplicate the pulsed US treatment, and infrared radiation to provide a heating effect only. Ten subjects were randomly assigned to each of four treatment groups and the distal humeral segment of the ulnar nerve was treated. Statistically significant changes in both nerve conduction velocity (NCV) and subcutaneous tissue temperature were associated with each treatment. Continuous US and infrared radiation treatments were associated with increased temperatures (0.8C) and increased velocities (3.75 and 3.08m/sec, respectively). Pulsed and placebo US treatments were associated with decreased temperatures (2.2C and 3.1C, respectively) and decreased velocities (2.79 and 5.38m/sec, respectively). Similar levels and patterns for NCV and subcutaneous tissue temperature were observed for the continuous US and the infrared groups, and for the pulsed US and the placebo US groups. Additionally, placebo US and infrared radiation treatments produced opposite temperature and velocity changes, while not contributing any mechanical effects. It was concluded that the mechanical effects of US were not significantly operative in this study. The increased velocities associated with continuous US and infrared radiation treatments were attributed to a thermal-heating effect, and the decreased velocities associated with placebo and pulsed US treatments were attributed to a thermal-cooling effect of the US transmission gel.     

Electrophysiologic recovery of acute conduction block of rat tail nerve

The recovery of experimental compression neuropathy with prolonged conduction block of the caudal nerve was studied electrophysiologically in 48 adult Sprague-Dawley albino rats divided equally into six groups. The pressure applied in groups A, B, C, D, E, and F was approximately 20kg/cm2 for 20 minutes, 20kg/cm2 for 10 minutes, 20kg/cm2 for 5 minutes, 10kg/cm2 for 20 minutes, 20kg/cm2 for 10 minutes, and 10kg/cm2 for 5 minutes, respectively. The motor nerve conduction velocity (NCV) and the amplitude of the evoked compound muscle action potential (CMAP) were measured before and periodically after nerve compression. The period of initial complete block was significantly longer in the high pressure groups than in the lower ones, and also significantly longer in the nerves compressed for 20 minutes than for those compressed for five or ten minutes. Thus, the severity of conduction block seems to be related to both pressure and duration of compression. Once the conduction block began to recover, the recovery rate of conduction block (recovery rate of amplitude ratio of CMAP, proximal/distal) was not significantly different. The recovery rate of demyelinative lesion (NCV recovery rate) was also not significantly different among the six groups. The degree of compression seems to determine the severity of the initial conduction block, but not the subsequent recovery rate of conduction.     

Dorsal ulnar cutaneous nerve conduction studies in an asymptomatic population

OBJECTIVES: To establish the average distal sensory latency and amplitude of the dorsal ulnar cutaneous nerve under controlled temperature and settings. DESIGN: Dorsal ulnar cutaneous nerve conduction studies were performed with a bar electrode between the fourth and fifth metacarpals. The nerve was stimulated at 8 and 10cm from the active electrode. The temperature of the limbs under study was kept at 32 degrees C to 35 degrees C. PARTICIPANTS: Fifty-four arms of 27 subjects were studied. RESULTS: Results showed that distal sensory latencies were normally distributed. The average distal sensory latencies at 8cm and 10cm were 1.84 +/- .20msec and 2.09 +/- .21msec, respectively, with average amplitudes of 26.5 +/- 9.7microV and 23.5 +/- 8.8microV. Comparison with a previously reported study in which the limb temperature was not controlled showed a statistically significant difference. CONCLUSION: It is important to use standardized technique and to measure and maintain optimal temperature of the arm under study to prevent erroneous results and misdiagnosis.     

Effect of gender on orthodromic sensory nerve action potential amplitude

OBJECTIVE: Studies in the literature have demonstrated a gender effect on sensory nerve action potential (SNAP) amplitude for the median and ulnar nerves by use of the antidromic method of recording. The objective of this study was to determine if performing orthodromic sensory nerve stimulation eliminates the gender bias by removing the finger circumference as a variable. METHODS: Fifty-five healthy subjects participated in the study. The mean age of the subjects was 37.8 +/- 5.9 yr and 35.3 +/- 5.9 yr for men and women, respectively. Orthodromic sensory nerve conduction studies were performed for the median and ulnar nerves measuring the SNAP amplitude by use of standard electrophysiologic technique. RESULTS: The mean finger circumference of the third digit was 6.5 +/- 0.58 cm for men and 5.9 +/- 0.47 cm for women, and for the fifth digit, it was 5.6 +/- 0.41 cm for men and 5.3 +/- 0.37 cm for women. The median SNAP amplitude and their percentiles of 2.5 and 97.5 for the median nerve were 30.0 microV for men and 28.0 microV for women. For the ulnar nerve, they were 16.5 microV for men and 16.0 microV for women. CONCLUSION: The study confirmed that orthodromic sensory nerve stimulation did not have any significant effect on SNAP amplitude between men and women.     

Ultrasound effects on electroneuromyographic measures in sensory fibers of the median nerve

The purpose of this study was to clarify the available literature and study the influence of ultrasound on the conduction velocity and amplitude of evoked sensory potentials in the median nerve. Thirteen subjects were assigned to either Experimental or Control Groups for ultrasound or placebo treatments. We compared sensory-nerve conduction velocity in the median nerve after 10 minutes of ultrasound treatment at three intensity levels (0.5, 1.0, and 1.5 W/cm2) with sensory-nerve conduction velocity in the median nerve after 10 minutes of placebo ultrasound treatment (0.0 W/cm2). No significant differences were noted between groups at any of the three ultrasound intensity levels, nor were the interaction effects significant. A hypothetical model, based on the available literature, proposes that ultrasound-induced changes in sensory-nerve conduction velocity may not progress in a direct linear fashion relative to the duration of treatment.     

Sensory conduction in the musculocutaneous nerve

This report describes an antidromic technique for studying conduction in the sensory branch of the musculocutaneous nerve, the lateral cutaneous nerve of the forearm. Surface stimulation was done at the elbow where the nerve becomes superficial, and surface recordings were made 12 cm distally over the course of the nerve. Sixty nerves in 30 normal persons were examined. The mean latency to onset of the action potential was 1.8 +/- 0.1 msec with a mean conduction velocity of 65 +/- 3.6 meters/sec. Mean amplitude of the action potential was 24 +/- 7.2 muv.     

Monochromatic infrared irradiation (890 nm): effect of a multisource array upon conduction in the human median nerve.

OBJECTIVE: Antidromic conduction studies in the human median nerve were used to assess the neurophysiological effects of irradiation of the skin overlying the nerve using a novel treatment unit comprising a multisource monochromatic infrared diode array (Equilight, Denver, CO). MATERIALS AND METHODS: Healthy human volunteers (n = 40) were recruited and randomly allocated to one of four groups: control, placebo, or one of two treatment groups (1.7 and 4.0 J/cm2). After baseline recordings of negative peak latency (NPL) were completed on the nondominant arm, subjects were treated according to group allocation. Recordings were subsequently repeated at 5-min intervals over a 45-min period. RESULTS: Analysis of negative peak latency difference scores (ANOVA) demonstrated significant differences in NPL between groups and over time (p < 0.05). While in the control and placebo groups NPL values remained relatively stable, in the two treatment groups such values decreased marginally, with the greatest effects observed in the 4.0 J/cm2 group (e.g., at 5 min, differences in NPL [mean +/- SEM]: control group, 0.02+/-0.03 msec; treatment group 2, 4 J/cm2, -0.07+/-0.03 msec). Similar significant differences were observed in skin temperature; correlation analysis indicated a weak (but expected) positive linear relationship between skin temperature and nerve conduction velocity (r = 0.125). CONCLUSION: These results suggest that irradiation at the parameters and under the conditions used here produce a direct neurophysiological effect. The magnitude of such effects are in keeping with previous findings using single source arrays at higher radiant exposures or thermal effects of the treatment unit.     

Paired study of the dorsal cutaneous ulnar and superficial radial sensory nerves

Nerve conduction studies of the dorsal cutaneous ulnar nerve (DCU) have been suggested as a useful technique for identifying distal ulnar nerve lesions. In this study a standardized method was used to establish normal conduction parameters of the DCU that were compared to conduction parameters of the superficial radial sensory nerve (SR) in the same extremity. Fifty-five extremities of 33 neurologically healthy subjects aged 22 to 69 years (mean = 37; SD = 13) were examined. Dorsal hand skin temperature of each subject was 31 to 36 C. The DCU and SR were antidromically stimulated 14cm proximal to plastic-mounted bipolar electrodes placed on the dorsum of the hand over each nerve. Latency to onset, latency to peak, and amplitude (mean +/- 2SD) for the DCU were 2.2 +/- 0.3msec, 2.8 +/- 0.5msec, and 24 +/- 17 microV; and for the SR were 2.2 +/- 0.3msec, 2.8 +/- 0.3msec, and 32 +/- 18 microV, respectively. Significant correlations (p less than 0.005) were found between the DCU and SR latencies to onset, and DCU and SR latencies to peak. These results suggest that distal sensory latencies of the DCU and SR are similar, and that a paired study of these nerves may be useful in distinguishing distal ulnar nerve entrapment syndromes when routine studies are equivocal.     

Electrophysiologic recording and thermodynamic modeling demonstrate that helium-neon laser irradiation does not affect peripheral Adelta- or C-fiber nociceptors

The effect of helium-neon laser irradiation (632.5 nm) on A delta- and C-fiber sensory afferents was investigated in the rabbit cornea, to determine the physiologic basis for reports that low power (0.1-5 mW) helium-neon (He-Ne) lasers produce acute analgesia and alleviate chronic pain. Multiple and single unit extracellular recordings from nociceptive corneal afferent nerves (C-fiber cold, C-fiber chemical, A delta mechanical and A delta bimodal) were used to study the effects of He-Ne laser radiation upon the electrophysiologic responses to mechanical, thermal, chemical and electrical stimulation of the cornea. Action potentials were analyzed for latency, amplitude, rise time, duration and frequency. Exposure of the neural receptive field and/or nerve bundle to a 4-mm diameter He-Ne laser (0-5 mW; 0-1800 sec) did not alter spontaneous or evoked neural activity. In addition, single unit action potential parameters were not altered by laser irradiation. Modeling of thermal changes produced by He-Ne radiation on corneal nerves indicated that effects predicted for receptor and axonal depths in both skin and cornea were minimal (less than 0.15 degrees C) and unlikely to alter sensory transduction or transmission.     

Correlation studies of velocity, amplitude, and duration in median nerves

Nerve conduction velocity is the parameter most often attended to when performing nerve conduction studies, but amplitude and duration of the nerve potentials should also provide important information about the status of the nerve examined. This study compared the results of amplitude and duration measurement to nerve conduction velocity to determine whether or not the various parameters correlated. Using standard techniques, median nerve motor and sensory conduction studies were performed on 390 unselected patients. The results were analyzed and correlation statistics calculated between the parameters of velocity, duration, and amplitude. Amplitude and duration of evoked potential correlated relatively poorly with conduction velocity (r2 = 0.26). Sensory and motor fibers were often affected differently in cases with probable carpal tunnel syndrome (CTS). Proximal motor conduction velocity correlated best with distal evoked potential amplitude (r2 = 0.27) in the CTS cases. The use of residual latency appeared to add little helpful diagnostic information. It was concluded that different parameters measure different physiologic processes that are to a considerable degree independent of each other.     

Medial and lateral antebrachial cutaneous nerves: standardization of technique, reliability and age effect on healthy subjects

Techniques for performing antidromic conduction velocity studies on forearm sensory nerves were evaluated in 157 healthy subjects from 17 to 80 years of age. The lateral antebrachial cutaneous nerve (LABCN) and the medial antebrachial cutaneous nerve (MABCN) were studied in the same upper extremity at a distance of 14 cm. The mean values for LABCN were amplitude 18.9 microV, latency to peak 2.8 ms and conduction velocity (CV) 61.5 m/s; for MABCN, amplitude 11.4 microV, latency to peak 2.7 ms and CV 62.7 m/s; and for median nerve, CV 62.3 m/s. SNAPs were obtained in 98% of subjects for each forearm sensory nerve. Age-related changes in the MABCN and LABCN were small, but included a decreased number of high value SNAP amplitudes and CVs with advancing age, whereas values for the median nerve showed a slight overall decrease with age. Sex effects were negligible. It is concluded that: LABCN and MABCN conduction studies can be performed with equal and high reliability using standard techniques and the same constant distance; The amplitude of the LABCN tends to be larger than that of the MABCN (76% of subjects); In some subjects MABCN studies are technically more difficult to perform than LABCN studies; Forearm sensory nerve studies may be used in addition to median nerve sensory studies in the evaluation of peripheral neuropathy, brachial plexopathy and local neuropathic conditions.     

Ultrasound and laser therapy in the treatment of carpal tunnel syndrome

This study was designed to compare the efficacy of ultrasound and laser treatment for mild to moderate idiopathic carpal tunnel syndrome. Ninety hands in 50 consecutive patients with carpal tunnel syndrome confirmed by electromyography were allocated randomly in two experimental groups. One group received ultrasound therapy and the other group received low level laser therapy. Ultrasound treatment (1 MHz, 1.0 W/cm(2), pulse 1:4, 15 min/session) and low level laser therapy (9 joules, 830 nm infrared laser at five points) were applied to the carpal tunnel for 15 daily treatment sessions (5 sessions/week). Measurements were performed before and after treatment and at follow up four weeks later, and included pain assessment by visual analogue scale; electroneurographic measurement (motor and sensory latency, motor and sensory action potential amplitude); and pinch and grip strength. Improvement was significantly more pronounced in the ultrasound group than in low level laser therapy group for motor latency (mean difference 0.8 m/s, 95% CI 0.6 to 1.0), motor action potential amplitude (2.0 mV, 95% CI 0.9 to 3.1), finger pinch strength (6.7 N, 95% CI 5.0 to 8.2), and pain relief (3.1 points on a 10-point scale, 95% CI 2.5 to 3.7). Effects were sustained in the follow-up period. Ultrasound treatment was more effective than laser therapy for treatment of carpal tunnel syndrome. Further study is needed to investigate the combination therapy effects of these treatments in carpal tunnel syndrome patients.     

Identification and characterization of afferent periodontal C fibres in the cat.

The presence of afferent periodontal C fibres was studied in pentobarbitone-anaesthetized cats. Extracellular single-fibre recordings were made from fine nerve filaments split from the proximally cut end of the inferior alveolar nerve. Periodontal nerve fibres were identified by constant-current stimulus pulses applied via platinum wire electrodes inserted into the periodontal space. Of 260 periodontal nerve fibres, 142 (55%) were classified as C fibres according to their conduction velocities (less than or equal to 2.5 m/sec) as determined by electrical stimulation of the periodontal ligament (c.v.p). The mean (+/- S.D.) c.v.p was 1.2 +/- 0.6 m/sec (n = 142; range: 0.3-2.5 m/sec). In addition, the axonal conduction velocity of 14 periodontal C fibres was determined by bipolar electrical stimulation of the trunk of the inferior alveolar nerve (c.v.n). On average the c.v.n was 42% higher than the c.v.p; the mean value was 1.7 +/- 0.8 m/sec (n = 14; range: 0.6-3.9 m/sec). Nevertheless, the classification of nerve fibres based on c.v.p proved to be reliable; only 1 fibre had a c.v.p less than 2.5 m/sec and a c.v.n greater than 2.5 m/sec and a c.v.n greater than 2.5 m/sec and was therefore reclassified as an A delta fibre. The responses of 30 electrically identified periodontal C fibres were tested by mechanical, thermal and chemical stimuli applied to the periodontal space. Thirteen of 19 periodontal C fibres tested responded to a strong mechanical force applied to the tooth from different directions while none could be activated by slight touch. A rudimentary directional sensitivity was observed.(ABSTRACT TRUNCATED AT 250 WORDS)     

干燥综合征伴周围神经病变的临床电生理与病理特点

目的 探究干燥综合征伴周围神经病变的临床电生理与病理特点.方法 以2018年1月至2021年1月收治的50例干燥综合征伴周围神经病变患者为试验组,同时以50例干燥综合征不伴周围神经病变患者为对照组.分析试验组临床电生理以及病理特点,比较两组患者临床表现的差异性.结果 试验组感觉神经传导异常患者中,10.00％为尺神经受...     

Physiological Localization by Sensory and Motor Inching Studies and Structural Abnormalities Detected by Ultrasonographic Changes in Carpal Tunnel Syndrome

ObjectiveTo study mild to moderate carpal tunnel syndrome (CTS), compare median nerve entrapment sites detected by electrophysiological inching studies with ultrasonographic abnormalities of cross-sectional area (CSA), and correlate focal points of conduction delays detected by sensory and motor inching recorded from the third digit and second lumbrical muscle.DesignAnalytic cross-sectional study.SettingDepartment of Rehabilitation Medicine, King Chulalongkorn Memorial Hospital, Bangkok, Thailand.ParticipantsHands from 10 participants without CTS (n=15) and hands with mild to moderate CTS from 29 participants (n=40) were selected by convenience sampling (N=55).InterventionsNot applicable.Main Outcome MeasuresCorrelation of electrophysiological entrapment site localization by inching study with anatomic entrapment site detected by ultrasound (US).ResultsIn all 40 hands tested, a sharply localized latency was found to increase across a 1-cm segment, most commonly 2-3 cm distal to the distal wrist crease for both sensory and motor studies, showing a good match between the 2 with Pearson correlation coefficient value (r=0.72). US revealed a narrowing CSA of the median nerve at 1-2 cm distal to the distal wrist crease.ConclusionsThis study showed a high correlation for focal point conduction delay detected by sensory and motor nerve conduction study. Recording from the second lumbricalis facilitated motor inching along the straight course of the nerve instead of the arcuate recurrent branch innervating the abductor pollicis brevis, the muscle traditionally used. US examination also revealed a localized narrowing of the median nerve CSA at 1-2 cm distal to the distal wrist crease, a possible site for anatomic entrapment. The most enlarged CSA was seen at the distal wrist crease, a level corresponding to the inlet of the carpal tunnel.