Diagnostic value of the F-reaction in localization of the level of peripheral motor neuron lesions

F-wave is a secondary muscle response, which occurs by antidromic activation of the limited number of alphamotoneurons. Based on M- and F-response and the nerve length, the conduction time, conduction velocity, and the ratio of F-response can be determined. These parameters help in assessing the data about functional condition of peripheral motor neurons along the most proximal segment in relatively simple and non-invasive way. In routine practical work, minimal latency of F-wave is measured, while F-wave conduction time, F-wave conduction velocity and F-ratio are not measured. The aim of this research was to examine the importance of F-wave latency, F-wave conduction time, F-wave conduction velocity, and F-ratio in the localization of level of lesion of peripheral motor neurons. Electromyoneurography examination included 50 patients with radiculopathies of lumbosacral part of spinal cord, 50 patients with neuropathy, and 25 healthy persons. Minimal latency of F-wave for tibial nerve and peroneal nerve was determined after 10 stimulations. F-wave latency, F-wave conduction time, F-wave conduction velocity, and F-ratio were determined in accordance with the formulas defined by Kimura. The results of our test have shown that F-wave latency, F wave conduction time, F-wave conduction velocity, were important electrophysiological parameters, while F-ratio was found to be highly sensitive, which made it the most valid electro-physiological parameter in the differentiation of proximal and distal lesion of peripheral motor neuron.     

Influence of magnetic resonance imaging on evoked potentials and nerve conduction velocities in humans

The authors investigated the influence of a 1.0-T magnetic field of a magnetic resonance (MR) imaging device, as well as the possible effects of the changing magnetic field and the RF field, on somatosensory, visual, and auditory evoked potentials and on peripheral nerve conduction velocities. The neural potentials outside and inside the static magnetic field were recorded before and after MR imaging. The measured latencies before and after MR imaging were within the normal range for healthy volunteers. The magnetic field did not significantly alter central or peripheral conduction velocities.     

Relationships between the integrity and function of lumbar nerve roots as assessed by diffusion tensor imaging and neurophysiology

Purpose

Diffusion tensor imaging (DTI) has shown promise in the measurement of peripheral nerve integrity, although the optimal way to apply the technique for the study of lumbar spinal nerves is unclear. The aims of this study are to use an improved DTI acquisition to investigate lumbar nerve root integrity and correlate this with functional measures using neurophysiology.

Methods

Twenty healthy volunteers underwent 3 T DTI of the L5/S1 area. Regions of interest were applied to L5 and S1 nerve roots, and DTI metrics (fractional anisotropy, mean, axial and radial diffusivity) were derived. Neurophysiological measures were obtained from muscles innervated by L5/S1 nerves; these included the slope of motor-evoked potential input-output curves, F-wave latency, maximal motor response, and central and peripheral motor conduction times.

Results

DTI metrics were similar between the left and right sides and between vertebral levels. Conversely, significant differences in DTI measures were seen along the course of the nerves. Regression analyses revealed that DTI metrics of the L5 nerve correlated with neurophysiological measures from the muscle innervated by it.

Conclusion

The current findings suggest that DTI has the potential to be used for assessing lumbar spinal nerve integrity and that parameters derived from DTI provide quantitative information which reflects their function.

     

Nerve conduction study of ulnar nerve in volleyball players

Ulnar neuropathy at the elbow is a common disorder seen in the throwing athlete. The purpose of our study was to determine whether asymptomatic physically active volleyball players and non-actives demonstrate distinct differences in nerve conduction of the ulnar nerve at the elbow. Nerve conduction studies were performed on both arms of 24 male volleyball players and 24 male non-actives. Nerve conduction velocity at the above to below elbow segment of the ulnar motor nerve were slower in the volleyball players compared with controls and their non-dominant arms. There were no statistical differences in latencies and conduction velocity of the ulnar nerve on the forearm, both in volleyball players and in the controls. In the evoked responses of the ulnar nerve, the amplitude was the same as corresponding normal values in both sensory nerve and muscle action potentials. We conclude that abnormal ulnar (motor) nerve conduction at the elbow segment may suggest a subclinical entrapment neuropathy as a result of strenuous elbow movements in volleyball players.     

Timing of cortical activation: a latency-resolved event-related functional MR imaging study

BACKGROUND AND PURPOSE: The time course of cortical activations of different anatomic areas has been demonstrated to reflect, to some degree, the temporal dynamics of the brain network. The purpose of this study was to determine the temporal sequence of the hemodynamic response in the visual, supplemental motor (SMA), and primary motor cortical areas by using a visuomotor reaction time task. METHODS: The reaction times (RTs) of 26 right-handed subjects were recorded in response to a visual cue during an event-related functional MR imaging (fMRI) experiment. Statistical parametric mapping (SPM99) was used, and activation maps were produced for each subject. This was followed by a random-effects group analysis. Using a weighted least-squares approach, we recorded the time at onset of the hemodynamic response of the fMRI activation in four regions of interest: the right occipital (RO) and left occipital (LO) visual cortices, the SMA, and the left sensorimotor area (LM1). Linear regression analysis was done between the RTs and the mean latencies for the four areas. RESULTS: Using the group analysis, the results showed that the first regions to activate were the visual occipital cortices (RO and LO) with mean latency +/- standard error of mean (SEM) of 1.74 +/- 0.05 s and 1.85 +/- 0.08 s, respectively. The visual occipital areas were followed by the SMA of 2.07 +/- 0.16 s and finally the LM1 with a mean latency of 2.1 +/- 0.15 s. There were significant differences in the mean onset of latencies between RO and LO, RO and SMA, and RO and LM1 (P <.05). On performing regression analysis between the RTs and the mean latencies by using the group analysis, there was no significant correlation with any of the four areas. By using an individual subject analysis, the results again showed that the first regions to activate were the visual occipital cortices (RO and LO) with mean latency +/- SEM of 1.75 +/- 0.06 s and 1.84 +/- 0.12 s, respectively, followed by the SMA with a mean latency of 2.19 +/- 0.25 s and finally the LM1 of 2.26 +/- 0.38 s. There was no significant difference between the mean onset latencies. CONCLUSION: The onset of the hemodynamic response started first in the visual cortex (input) followed by the SMA and primary motor cortical area (output). The onset of activation showed no direct correlation with the overall RTs of the subjects, leading one to suggest that the peripheral motor unit may have a greater impact on RT than the central contribution.     

Comparison of nerve conduction velocities of lower extremities between runners and controls

Peripheral nerve injuries can occur in runners, but large numbers of nerve injuries remain subclinical. Identification of nerve injuries needs an understanding of common sites of entrapment in running. Fourteen asymptomatic male middle-distance runners and 14 non-active subjects participated in this study. The neurophysiologic study consisted of motor and sensory nerve conduction of medial and lateral plantar nerves, sensory nerve conduction of sural and superficial peroneal nerves, and motor nerve conduction of common peroneal nerve. Active range of motion and muscle strength assessment (dorsi flexion/plantar flexion; inversion/eversion) as measured using a Biodex System3 Dynamometer were observed to be within normal limits for both groups. The medial plantar (sensory) nerve and sural nerve distal latencies were significantly prolonged and sensory conduction velocities were significantly delayed in the runners compared with the control subjects. Many of the asymptomatic runners with abnormal nerve conduction tests in this study may represent presymptomatic or asymptomatic neuropathy similar to the type of subclinical entrapment neuropathy.     

一家系2例遗传性压迫易感性神经病报道

目的 报道一家系2例遗传性压迫易感性神经病(HNPP),以提高对本病的认识及诊断水平。方法 2例均行详细肌电图、运动及感觉神经传导速度、运动神经远端潜伏期测定。1例行腓肠神经活检,标本分别在光镜或电镜下观察。结果 例1临床表现为反复的压迫或牵拉后肢体无力和麻木。例2为例1父亲,临床无发病,查体有周围神经病表现。2例电生理检查示广泛性神经传导速度减慢,特别是周围神经嵌压部位运动传导速度减慢更明显,运动神经远端潜伏期延长,包括临床未受累的神经。腓肠神经活检电镜见大多数有髓纤维髓鞘增厚,有的髓鞘向轴索内突出,轴索未见异常。无葱皮样改变。无髓纤维未见显变。结论 神经电生理检查是诊断HNPP重要的筛选手段,确诊有赖于腓肠神经活检的典型病理表现。     

F波各参数对糖尿病周围神经病的诊断敏感性

 目的 探讨F波各参数中对诊断糖尿病周围神经病(diabetic peripheral neuropathy,DPN)的敏感指标。方法 随机选取81例2型糖尿病患者,检测其正中神经、尺神经、胫神经神经的传导速度(nerve conduction velocity,NCV)、F波。根据NCV结果分为NCV正常组和NCV异常组,比较两组同名神经各参数指标,比较NCV异常组各神经的F波与MCV异常率。结果 糖尿病患者各神经F波最长潜伏期总异常率高于最短潜伏期、平均潜伏期、F波出现率、F波最大传导速度的总异常率,差异有统计学意义(P<0.05)。与NCV正常组比较,NCV异常组正中神经F波的最短潜伏期、最长潜伏期、平均潜伏期、最大速度差异有统计学意义(P<0.05),两组其他同名神经参数比较均无统计学差异。NCV异常组胫神经、正中神经、尺神经F波异常率明显高于同一神经的运动神经传导速度(motor nerve conduction velocity,MCV)异常率,差异有统计学意义(P<0.05)。结论 F波最长潜伏期对DPN的诊断较敏感,NCV联合F波可以提高DPN的检出率。     

Therapeutic cooling: no effect on hamstring reflexes and knee stability

PURPOSE: Stretch reflexes contribute to joint stiffness, but the effects of therapeutic cooling on these reflexes are unknown. Therapeutic cooling is frequently used in knee rehabilitation, for instance, after rupture of the anterior cruciate ligament. Cooling a joint can affect nerve conduction velocity and the function of sensory organs. Such changes in neuromuscular coupling could reduce knee stability and increase the risk of knee injury. The aim of the present study was to evaluate whether there are negative effects of knee cooling on the hamstring short and medium latency reflex responses or on the anterior tibia trajectory after mechanically induced tibia translation. METHODS: In 15 healthy volunteers, the latency and size of short latency and medium latency reflex responses of hamstring muscles were assessed before and after 20 min of cold therapy of the knee joint as applied in rehabilitation. Reflex responses were evoked by a mechanically induced posterior-anterior tibia translation during standing. Reflexes were recorded by surface electromyography. The distance of anterior tibia motion and its velocity were assessed by potentiometric position transducer. RESULTS: Local cold therapy of the knee did not alter the latency or the size of short or medium latency responses. Also, the extent and the velocity of tibia translation were unchanged after knee cooling. CONCLUSION: Cold therapy does not seem to adversely influence the spinal reflexes of the hamstrings induced by anterior tibia translation. As neuromuscular coupling was not significantly affected, the cold therapy, as performed in the present study, is not likely to increase the risk of knee injury.     

Evaluation of median nerve in children with type1 diabetes using ultrasonographic imaging and electrophysiology

Background

Diabetic peripheral neuropathy (DPN) is a worldwide costly complication of diabetes.

Objective

To evaluate the relationship between the sonographically measured cross-sectional area (CSA) of the median nerve and nerve conduction study (NCS) in children with type1 diabetes (T1DM) complaining of DPN.

Material and methods

Forty children with T1DM and 20 age-matched healthy subjects were enrolled in this study. The diabetic children were divided into 2 groups (without and with DPN). All participants underwent NCS and sonographic measurement of CSA for the median nerve in the carpal tunnel.

Results

The CSA of the median nerve in children with DPN was higher than that in the control subjects yet with no significant difference with that of children without DPN. The increased median nerve CSA in the carpal tunnel was considerably correlated with the median nerve motor latency and duration of diabetes, nevertheless, with no correlation with median nerve motor conduction velocity (MNCV).

Conclusion

Sonographic measurement of CSA of the median nerve in the carpal tunnel serves as a good discriminator for diabetic children from healthy individuals. Moreover, it has significant positive correlation with duration of disease and the nerve motor latency.     

周围神经选切治疗痉挛性脑瘫中电刺激阈值的意义探讨

目的：探讨在周围神经选切治疗痉挛性脑瘫中阈值的意义。方法：41例痉挛性脑瘫,16例SPR和18例SAR术中电刺激脊神经前后根神经小束,28例经皮刺激坐骨神经,观察相应肌肉运动诱发反应,25例取周围神经标本40个,进行秀射电镜观察。结果：电刺激神经小束或坐骨秀发的肌肉收缩反应或M波幅,存在着最大,最小现象,当达到最大后,保持稳定,不再随刺激强度增大而增加,周围神经呈原发性脱髓鞘病变,有髓纤维病变明显无髓纤维,粗纤维重于细纤维。结论：在周围神经选切治疗痉挛性脑瘫中,阈值作为判断所切神经小束中能够基本正常发挥有髓纤维声望地功能的纤维含量,存在着一定的可行性。     

吉兰-巴雷综合征颅神经受损的临床特点及启示意义

目的总结颅神经受累的吉兰-巴雷综合征（Guillain-Barre syndrome,GBS）的临床特点、辅助检查结果及疗效。方法收集2005年1月1日-2011年12月31日收治的25例伴有颅神经受损的吉兰-巴雷综合征患者资料,结合文献进行分析。结果 25例中,颅神经单独受累者6例,脊神经和颅神经同时累及19例。脑脊液检查16例中,蛋白-细胞分离10例。电生理检查19例中,异常18例;其中运动神经潜伏期延长6例,波幅减低5例,神经传导速度减慢5例,运动单位电位减少或消失3例,F波减少或消失8例。急性期单独使用免疫球蛋白治疗11例,好转9例。糖皮质激素联合免疫球蛋白治疗9例,好转6例;1例出现严重呼吸肌受累而行呼吸机辅助呼吸,激素联合免疫球蛋白治疗病情仍进行性加重,后行血浆置换好转。单纯使用糖皮质激素治疗3例,好转2例。结论吉兰-巴雷综合征颅神经受累以舌咽及迷走神经较为常见,其他如面神经、动眼神经和舌下神经也较易累及。颅神经可单独受累,也可与脊神经同时累及。确诊需依据临床、电生理及脑脊液检查。单独使用免疫球蛋白或激素联合免疫球蛋白治疗有一定疗效。     

Électromyostimulation et récupération fonctionnelle d’un muscle dénervé

Aim. – The purpose of this revue is to focus on research concerning the effect of chronic muscle electrical stimulation after denervation and reinnervation.Actuality. – The therapeutic use of electricity date back to ancient times, when the greeks used electric eels to treat physical ailment. Today electrotherapy is very commonly applied by certified athletic trainers. Alpha motor neurons conduct impulses from the spinal cord to the muscle. When the conduction of impulses to muscle is disrupted, the individual loses control of the affected muscle. When the nerve to the muscle is not functioning, the muscle is denervated, or without innervation. Unlike nerve fibers in the central nervous system, peripheral nerve fibers can regenerate and active control of the muscle can be restored.Perspectives and projects. – The efficacy of electrical stimulation of denervated muscle has not been established in human. Electrical stimulation does not bring about reinnervation; however a regularly stimulated muscle may recover force-generating capacity sooner if reinnervation occurs. In mammals, it has been show since several years that the regular stimulation of a denervated and reinnervated muscle promoted the motor function return. Recently, it has also been observed in animals, that muscle stimulation with a biphasic current was responsible to a more rapid return of the muscle sensibility. However, these preliminary works realized in the young mammals need to be improved.     

Plantar flexion torque as a function of time of day

The possible peripheral and/or central origin in the mechanisms responsible for day-time fluctuation in maximal torque of the triceps surae muscle were investigated with a special emphasis on antagonist muscle coactivation. Eleven healthy male subjects (physical education students) took part in this investigation. The electromechanical properties of the plantar flexor muscles were recorded at two different times of day: between 06:00 h and 08:00 h in the morning and between 17:00 h and 19:00 h in the evening. To investigate peripheral mechanisms, the posterior tibial nerve was stimulated at rest, using percutaneous electrical stimuli, to evoke single twitch, double twitch, and maximal tetanic contraction (100 Hz). Maximal voluntary contraction of the plantar flexors was also assessed by means of the relative electromyographic activity of respective agonist and antagonist muscles (soleus, gastrocnemius medialis, gastrocnemius lateralis, and tibialis anterior). A double twitch was delivered during maximal voluntary plantar flexion to record muscle activation (i.e., interpolated twitch technique). The coactivation level of the tibialis anterior muscle during plantar flexion was calculated. The results indicated a significant decrease in maximal voluntary muscle torque of triceps surae in the evening as compared with the morning (-7.0 %; p < 0.05). Concerning the central command, when extrapolated by the twitch interpolation technique, the decrease in mean activation level of -6.8 % was consistent with the fluctuation in torque (-7.0 %). Soleus muscle electromyographic activity (normalized to the M-wave) showed a significant decline (21.6 %; p < 0.001). Moreover, individual changes in MVC percentage were significantly related to those of normalized electromyographic activity of the soleus muscle (r = 0.688; p < 0.01). Thus, it indicated that the subject's capacity to activate the soleus muscle was affected by the time of day. The coactivation level in the tibialis anterior muscle during plantar flexion did not change significantly in the evening. Concerning peripheral mechanisms, we observed a decrease in maximal M-wave amplitude for soleus and gastrocnemii, associated with unchanged single twitch and tetanus torque. To conclude, impairment in soleus muscle central command seemed to be the mechanism in the origin of torque failure. Such information would be of importance in the investigation of day-time fluctuations in complex motor task performances implicating the triceps surae muscle.     

Evaluating the contribution of reactive balance to prediction of fall rates cross-sectionally and longitudinally in persons with multiple sclerosis

BackgroundFalls are common in persons with multiple sclerosis (PwMS). Reactive postural control—one’s response to a balance perturbation—is likely an aspect of fall risk; however, the relationship between reactive posture and falls is poorly understood in PwMS.ObjectiveWe evaluated tibialis anterior muscle onset latency (TA latency) after balance perturbations as a predictor of fall rates in PwMS, controlling for clinical, functional, sensory, psychological, and cognitive factors.MethodAt baseline of the 18-month cohort study, 122 participants with MS (EDSS = 2.23) were included. Assessments were conducted every 6 months.ResultsOf the original 122 participants at the baseline collection, data were available from 41, 39, and 34 people at the 6, 12, and 18 month follow-ups, respectively. Percent fallers at the four time points were 35.3%, 12.2%, 15.4%, and 20.5%. Cross-sectionally (i.e., at baseline), the Timed Up-and-Go, Falls Efficacy Scale – International (FES-I), and TA latency after perturbations were significant predictors of retrospective falls rates using negative binomial regression. Longitudinally, random-effects negative binomial regression found that trait-level FES-I, Stroop Color-Word, and TA latency were significant predictors for falls rates.ConclusionDelays in automatic postural responses seem to account uniquely for fall rates in PwMS—beyond clinical, balance, or mobility measures. These delays may contribute to the increased fall rate in PwMS. In addition to brief self-report instruments (FES-I) and cognitive assessments, muscle onset after balance perturbations may be a valuable tool for predicting falls in those with MS.     

Modulation of prelanding lower-limb muscle responses in athletes with multiple ankle sprains

PURPOSE: The objective of this study was to investigate modulation in prelanding muscle responses and its associated impact force on landing from unexpected and self-initiated drops in male basketball players with a history of bilateral multiple ankle sprains (BMAS). METHODS: Prelanding EMG responses were recorded in four lower-limb muscles, together with the impact force on landing, while 20 healthy and 19 basketball players with BMAS performed unexpected, self-initiated drops from a height of 30 cm. RESULTS: Group differences were detected after self-initiated but not unexpected drops. Two main changes in prelanding EMG responses were observed in the injured basketball players during the self-initiated drops. First, tibialis anterior (TA) was activated significantly earlier in the injured group, whereas left tensor fascia latae appeared closer to the moment of landing (P < 0.025) than in the healthy players. Second, cocontraction indexes between left TA and peroneus longus, and left TA and medial gastrocnemius, were significantly greater in the injured than in the healthy players (P < 0.025). On landing, higher magnitude-of-impact forces were observed in the injured players on the right leg (by 23%, P = 0.012). CONCLUSION: In basketball players with BMAS, modulation of prelanding muscle response latencies occurred in injured (ankle) and uninjured (hip) joints during self-initiated but not unexpected drops. Greater cocontraction index between the left ankle muscle pairs in preparation for landing from self-initiated drops, and a significantly higher magnitude of impact force in the right leg on landing, were observed in the injured players.     

Total antioxidant blood capacity in patients with type 2 diabetes mellitus and distal symmetrical polyneuropathy

BACKGROUND/AIM: Reduced systemic antioxidant defence is considerd to play an important mediating role in pathogenesis of diabetic neuropathy. The aim of this study was to evaluate if the total antioxidant blood capacity (TAC) is reduced in patients with type 2 diabetes mellitus (DM) and diabetic distal symmetrical polyneuropathy (DDSP) and to correlate this antioxidant capacity with the degree of peripheral nerve dysfunction. METHODS: This study involved 100 patients with type 2 DM and signs of DDSP, as well as the control group of 50 healthy subjects. The evaluation of DDSP was based on physical examination and nerve conduction studies. The degree of peripheral nerve dysfunction was estimated by scoring and analysing sensory and motor nerve conduction parameters (distal latency and amplitude of evoked potential, conduction velocity). Laboratory analyses involved blood glucose and HbA1C levels, as well as plasma TAC. RESULTS: Blood glucose and HbA1C level was significantly higher in the patients than in the control group (p < 0.0001). The TAC was depleted in the diabetic group and the depletion was statistically significant (p < 0.0001). There was no significant correlation between the TAC and the serum glucose level, TAC and HbA1C level as well as between TAC and the duration of DM. There was no significant correlation between TAC and peripheral nerve conduction parameters. CONCLUSION: Total antioxidant blood capacity is reduced in patients with DDSP, but it does not correlate with blood sugar level, with the duration of DM or with the degree of functional nerve damage. These results show a reduced systemic antioxidant defence in patients with type 2 DM and DDSP. However, it is still unclear to what extent the oxidative stress is a contributing factor or leading cause of diabetic neuropathy, suggesting that further studies are necessary.     

Submaximal fatigue of the hamstrings impairs specific reflex components and knee stability

Rupture of the anterior cruciate ligament (ACL) is one of the most serious sports-related injuries and requires long recovery time. The quadriceps and hamstring muscles are functionally important to control stability of the knee joint complex. Fatigue, however, is an important factor that may influence stabilizing control and thus cause ACL injuries. The objective of this study was therefore to assess how submaximal fatigue exercises of the hamstring muscles affect anterior tibial translation as a direct measure of knee joint stability. While 15 test participants were standing upright with the knees in 30° of flexion, anterior tibial translation was induced by a force of 315 N. Two linear potentiometers placed on the tibial tuberosity and the patella recorded tibial motion relative to the femur. Reflex latencies and neuromuscular hamstring activity were determined using surface electromyography (EMG). Muscle fatigue produced a significant longer latency for the monosynaptic reflex latencies, whereas no differences in the latencies of the medium latency component were found. Fatigue significantly reduced EMG amplitudes of the short and medium latency components. These alterations were in line with significantly increased anterior tibial translation. Our results suggest that hamstring fatigue is effectively associated with mechanical loss of knee stability. This decrease in joint stability may at least in part explain higher risk of ACL injury, especially in fatigued muscles. Furthermore, we discuss why the present findings indicate that reduced motor activity rather than the extended latency of the first hamstring response is the reason for possible failure.     

Neural influence on cardiovascular and endocrine responses to static exercise in humans.

At the onset of exercise, signals from the central nervous system result in immediate vagal withdrawal and resulting increases in heart rate and arterial blood pressure. From the second heart beat peripheral nerve (reflex) influence from exercising muscle can be detected. With continued exertion, especially with large muscle groups, this influence becomes increasingly important. Sympathetic nerve signals to resting muscle can be influenced by the central nervous system, but are dominated by influence from 'metaboreceptors' in exercising muscle, while sympathetic nerve signals to skin are more influenced by the central nervous system. Cardiovascular responses to static contractions increase with the percentage of maximum contraction intensity as well as with the muscle mass involved. Plasma catecholamines rise in proportion to increases in cardiovascular variables and are influenced by a central nervous mechanism early in the contraction. Furthermore, during static contractions the increase in plasma adrenaline (epinephrine) is larger relative to that of noradrenaline than during dynamic exercise. Both catecholamine responses and the responses of pituitary hormones depend on the active muscle mass, but are small compared to those established during dynamic exercise. Experiments designed to enhance central command, resulting in increased cardiovascular and endocrine responses compared to control experiments and experiments in which an attenuation of peripheral nerve influence resulted in reduced changes in these variables during exercise, contrast with the notion that the 2 neural control mechanisms are redundant. Rather, the 2 neural influences on the autonomic nervous system work in concert in eliciting the responses manifest during static exercise.     

Nerve conduction studies of upper extremities in tennis players

Objectives: The influence of regular and intense practice of an asymmetric sport such as tennis on nerves in the elbow region was examined.

Methods: The study included 21 male elite tennis players with a mean (SD) age of 27.5 (1.7) years and 21 male non-active controls aged 26.4 (1.9) years. Anthropometric measurements (height, weight, limb length, and perimeters of arm and forearm) were determined for each subject, and range of motion assessment and radiographic examination carried out. Standard nerve conduction techniques using constant measured distances were applied to evaluate the median, ulnar, and radial nerves in the dominant and non-dominant limb of each individual.

Results: The sensory and motor conduction velocities of the radial nerve and the sensory conduction velocity of the ulnar nerve were significantly delayed in the dominant arms of tennis players compared with their non-dominant arms and normal subjects. There were no statistical differences in the latencies, conduction velocities, or amplitudes of the median motor and sensory nerves between controls and tennis players in either the dominant or non-dominant arms. However, the range of motion of the upper extremity was significantly increased in tennis players when compared with control subjects. Tennis players were taller and heavier than control subjects and their dominant upper limb lengths were longer, and arm and forearm circumferences greater, than those of the control subjects.

Conclusions: Many of the asymptomatic tennis players with abnormal nerve conduction tests in the present study may have presymptomatic or asymptomatic neuropathy similar to subclinical entrapment nerve neuropathy.