A Study of Somatic Nerve Functions in Diabetic and Normal Persons.

This hospital-based case-control study was undertaken among 50 diabetic cases and 50 non-diabetic controls of Burdwan to evaluate neurophysiological changes. Neurophysiological assessment was done with nerve conduction velocity, amplitude and latency of median nerve motor and sensory component of upper arms and tibial motor and sural sensory part of lower limbs. NCV and amplitude had negative correlation where latency had positive correlation with age and duration of diabetes. Independent t-test was done to compare NCV and amplitude among cases and controls and results showed diminished values in cases than controls (p< 0.001). This study reflected that early diagnosis and management of neuropathy by neurophysiological test may retard the progression of neuropathy in diabetic persons.

Comparative Analysis of Electrophysiological Parameters of Median Nerve in Normal and Diabetic Subjects.

Peripheral neuropathy is a common complication in diabetic patients. Nerve conduction study is widely used for the assessment of diabetic polyneuropathy. This study was designed to characterize motor nerve conduction abnormalities in subjects having relatively shorter duration (2.28 ± 1.51 years) of type 2 diabetes mellitus. The median motor nerve conduction study was carried out on 40 male type 2 diabetic patients attending diabetic clinic in the department of medicine and 40 healthy male volunteers who served as control. Motor Distal latency (MDL), Amplitude (Amp) and Conduction Velocity (CV) were measured. On comparing the parameters of median nerves of both the groups, it was found that motor distal latency of (right and left) median nerves was higher in diabetics than in non diabetics with statistically significant difference. Results also showed decreased amplitude and conduction velocities of median nerve of both sides in diabetics (statistically significant). All the parameters were found correlated with blood sugar levels in diabetics.

Obesity Affects Median Nerve Conduction - A Study in Armed Forces Individuals.

Background: Obesity, a growing public health concern, is associated with various disorders. Studies have suggested obesity as an independent risk factor that influences the prevalence of carpal tunnel syndrome (CTS) among active workers. The present study is an attempt to establish relationship between median nerve conduction velocity and obesity in people who do not have any other contributory factor for CTS other than obesity. CTS is the commonest entrapment neuropathy where the median nerve is compressed. Methods: The study was conducted in 15 obese subjects with Body Mass Index (BMI)>30 (group III) and 15 overweight subjects with BMI between 25&29.9 (group II) and 15 control subjects with BMI <25 (group I). The subjects were personnel from armed forces. Their body density was estimated using hydro-densitometry and the body fat percentage was calculated from density. The distal motor latency (DML) and the sensory conduction velocity (SCV) across the wrist on stimulation of median nerve at wrist 3cm proximal to distal crease were assessed in all subjects. Results: The mean values of DML in group I, II, and III were 3.52±0.25 ms, 3.50±0.30 ms and 3.65±0.20 ms respectively. Mean value of SCV among these groups were 48.99±3.23 m/s, 49.32±3.35 m/s and 48.69±4.00 m/s. Conclusion: No relationship could be established between BMI and DML as well as BMI and SCV. The relationship between percentage body fat and DML and SCV also found to be statistically insignificant. However, there was a correlation between BMI and body fat percentage. Carpal tunnel syndrome is uncommon even in obese armed forces personnel, which might be due to their regular body and hand exercise thereby having increased tone in hand muscles.

Anastomosis between median nerve and ulnar nerve in the forearm

Anastomosis between the median nerve and ulnar nerve can occur in the forearm region. It consists in crosses of axons which may produce changes in innervation of the upper limb muscles, mainly motor part of intrinsic muscles in the hand. Anastomosis in the forearm can be classified in two types: Martin Gruber anastomosis and Marinacci anastomosis. This study has as purpose to report the incidence, type, topography of anastomosis found and assess the length of this anastomosis. Material and Methods: For this study, 30 forearms were dissected in the Anatomy Institute of Severino Sombra University. In order to check the incidence of anastomosis and its topography, the length of the anastomotic branch was measured with a measuring tape (3M). In addition schematic drawings were executed. Results: Three (3) anatomical pieces that contained the Martin-Gruber anastomosis with an average length of 6.6 cm were found. One (1) anatomical piece with a 7.4 cm long Marinacci anastomosis was found, even though such type of anastomosis shows low incidence, and was found only in electroneuromyography studies. Conclusion: The study of anomalous communications between median and ulnar nerves in the forearm deserves great attention for its incidence and its clinical importance, mainly in the correct diagnosis of peripheral neuropathies, for example in the Carpal Tunnel Syndrome, which produces changes in the upper limb innervation. The importance of its verification and delimitation is also crucial to avoid lesions in surgical procedures.

Comparisons among different reference values of nerve conduction velocity in forensic appraisal / 法医学杂志

OBJECTIVE@#To provide the evidences for the choice of normal reference value of nerve conduction velocity (NCV) in clinical forensic appraisal.@*METHODS@#One hundred and fourteen cases with normal peripheral nerve and 155 cases with injured peripheral nerve were collected. The NCV of homonymous nerves in two limbs were detected. In the normal cases, the NCV of the left limbs were used as the normal reference values. The NCV of the right limbs were compared with that of left limbs, the commendatory normal reference values from Beijing Xiehe Hospital and Shanghai Huashan Hospital. In the injured cases, the results of NCV in injuried limbs were compared with the results of healthy limbs and the reference values from Beijing Xiehe Hospital and Shanghai Huashan Hospital.@*RESULTS@#In the normal group, there was no statistical difference between the left and right limbs in NCV results of homonymous nerve (P > 0.05). The false positive rates (FPR) were 0, 11.4% and 5.2% for three choices normal reference respectively. The false negative rates (FNR) were 0, 9.7% and 12.3% for three choices normal reference in injuried group. Thee false negative cases were all slight nerve injury.@*CONCLUSION@#The reference value of self-control method could decrease the FPR of normal cases and FNR of injured cases. In clinical forensic appraisal of peripheral nerve, the nerve condition study results from healthy homonymous nerve should be regarded as the reference value at first, supplemented by reference values from clinical labs.

Effect of neurotrophic factor, MDP, on rats’ nerve regeneration

Our objective was to determine the immune-modulating effects of the neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration in rats. We used male Wistar rats (120-140 days of age, weighing 250-332 g) and compared the results of three different techniques of nerve repair: 1) epineural neurorrhaphy using sutures alone (group S - 10 rats), 2) epineural neurorrhaphy using sutures plus fibrin tissue adhesive (FTA; group SF - 20 rats), and 3) sutures plus FTA, with MDP added to the FTA (group SFM - 20 rats). Functional assessments using the grasp test were performed weekly for 12 weeks to identify recovery of flexor muscle function in the fingers secondary to median nerve regeneration. Histological analysis was also utilized. The total number and diameter of myelinated fibers were determined in each proximal and distal nerve segment. Two indices, reported as percentage, were calculated from these parameters, namely, the regeneration index and the diameter change index. By the 8th week, superiority of group SFM over group S became apparent in the grasping test (P = 0.005). By the 12th week, rats that had received MDP were superior in the grasping test compared to both group S (P < 0.001) and group SF (P = 0.001). Moreover, group SF was better in the grasping test than group S (P = 0.014). However, no significant differences between groups were identified by histological analysis. In the present study, rats that had received MDP obtained better function, in the absence of any significant histological differences.

Analysis of compound muscle action potential of median and ulnar nerves: possible anatomical correlation

To analyze the shape of CMAP of both median and ulnar nerves in apparently healthy individuals, and the anatomical innervations of small muscles of hand in cadavers. Motor conduction studies of both median and ulnar nerves for 300 apparently healthy adults were performed. The nerve supply of both thenar and hypothenar muscles were dissected in 10 adult cadavers. The mean amplitude and the mean distal latency [MDL] of the median nerve were significantly higher than that of the ulnar nerve [11.785 +/- 5.0, 10.45 +/- 2.96 mV respectively, and 3.38 +/- 0.41 and 2.698 +/- 0.40 ms respectively]. The median nerve had mostly dome shaped rather than double peaked CMAP [p=0.0001], while in the ulnar nerve it was more frequently double peaked [p=0.0001]. The MDL of the median nerve was significantly longer in those with dome shaped CMAP, while in the ulnar nerve it was significantly longer in those with dome shaped [p=.0001]. There were no statistical significant differences between the amplitude of dome and double peaked CMAP in either median or ulnar nerve.. The anatomical results showed that abductor pollicis brevis is supplied by the median nerve in 90% of specimens, and by both nerves in 10%. The abductor digiti minimi brevis is supplied by the deep branch of the ulnar nerve in 90% and by superficial branch of the ulnar nerve in 10%. There was a connection between the median and ulnar nerves in 50% of specimens. Variability in the pattern of innervations of the small muscle of the hand could be a possible etiological factor for the difference in the CMAP configuration of the median and ulnar nerves

Sensory nerve conduction velocity is greater in left handed persons.

Dependence of nerve conduction velocity on factors like age, sex and temperature is well known. Effect of handedness on nerve conduction velocity has not been studied adequately. In this study correlation between handedness and motor as well as sensory conduction velocity of right as well as left median nerve was studied in 84 medical students in the age group between 17-21 years out of which 72 were right handed and 12 were left handed. In addition auditory and visual reaction times were also studied. Sensory conduction velocity in both right and left median nerve was significantly higher in left handers as compared with right handers whereas, the motor conduction velocity in right handers and left handers was not different. The auditory and visual reaction times were also not different in these groups. Because of greater sensory conduction velocity in left handers there is a requirement of different set of normal reference values for left handers in clinical diagnosis.

Chronic carpal tunnel syndrome: results of carbal tunnel release

Carpal tunnel syndrome [CTS] is the commonest entrapment neuropathy for which several conservative and surgical treatment options are available. In majority of cases the cause of CTS is unknown [idiopathic CTS], however, there are numerous medical conditions associated with CTS. Surgery for CTS is one of the most often performed procedures. The purpose of this study was to evaluate the clinical outcome of surgical treatment of chronic carpal tunnel syndrome. Thirty patients with chronic CTS were selected for open carpal tunnel release. Twenty patients had bilateral disease. Thirty hands had thenar muscle atrophy. Fifty hands of thirty patients were operated from May 1997 to December 2002. Sensation improved within three months in all patients. Nocturnal pain disappeared within first week after surgery. Grip strength improved gradually even up to two years after surgery. All of thirty hands with thenar muscle atrophy showed symptomatic relief, but recovery of the wasted muscle in term of regaining bulk was very slow in most of cases. Only ten hands showed complete recovery of bulk of thenar muscles in three years time. Surgery is an excellent treatment option in chronic CTS in terms of symptomatic relief. Wasted thenar muscles recover slowly in fraction of cases

Comparison of nerve conduction techniques in 95 mild carpal tunnel syndrome hands

Electrodiagnosis of carpal tunnel syndrome (CTS) were prospectively studied in 95 hands. The following techniques were studied in all hands when at least one abnormal value was found (onset-measured), it was included on results: 1. wrist-index finger latency (WIF), abnormal = 2.8 ms, 140 mm; 2. palm-wrist latency (PW), abnormal = 1.8 ms, 80 mm; 3. comparison median/ulnar palm-wrist latency (CPW), abnormal = 0.4 ms; 4. comparison median/ulnar latency, wrist-ring finger (CMU), abnormal = 0.5 ms, 140 mm; 5. comparison median/radial latency, wrist-thumb (CMR), abnormal = 0.4 ms, 100 mm. All 95 CTS hands selected have the WIF = 3.5 ms (mild CTS). We found the CMR (97.8 per cent) technique the most sensitive for mild CTS electrodiagnosis and the only comparative method with all potentials recordable when compared to CPW (88.4 per cent). PW (84.2 per cent), CMU (72.6 per cent) and WIF (68.4 per cent).

Síndrome do túnel do carpo: aspectos Clínico-epidemiológicos em 668 casos / Carpal tunnel syndrome: clinical and epidemiological studies in 668 cases

Foram estudados 668 pacientes (1059 mãos) com síndrome do túnel do carpo entre janeiro de 1989 e junho de 1996. O critério de seleção e inclusão dos pacientes baseou-se na diferença de latência sensitiva = 1,0 ms entre os potenciais de ação sensitivos dos nervos mediano e radial após estimulação no punho e registro no I dedo (diferença mediano-radial, DMR), representando diferença maior que 6 desvios-padrão (DP). Foi obtida DMR em 125 mãos normais (grupo controle) com limite superior de normalidade de 0,43 ms (média + 2DP). Todos os casos tiveram estudo eletrofisiológico bilateral, sendo exclído casos com cirurgia prévia ou evidência de neuropatia periférica. A idade variou de 17 a 83 anos com média de 47,5 anos; 91,3 por cento eram do sexo feminino; 72 por cento referiam sintomatologia bilateral e 85,3 por cento no período noturno/matinal. Dor, dormência e formigamento foram juntamente referidos por 64,4 por cento, sendo que dor como sintoma isolado foi raro; além da mão, houve extensão do quadro álgico para outros territórios em 39,4 por cento. Os sintomas ocorreram em todos dos dedos em 42,5 por cento seguido do III, III-IV, I-II-III e II-III-IV dedos. Não houve correlação precisa com antecedentes traumáticos no punho. A duração da sintomatologia foi ampla, variando de 1 a > 120 meses. A doença mais comumente referida pelos pacientes foi diabetes melitus com 4,4 por cento do total.

Síndrome do túnel do carpo: correlaçäo da comparaçäo de latência sensitiva mediano-radial com conduçäo nervosa. Rotina em 1059 mäo (668 casos) / Carpal tunnel Syndrome: sensory median-radial difference versus conduction studies in 1059 hands (668 cases)

Foram estudados 668 pacientes (1059 mãos) com síndrome do túnel do carpo (STC) entre janeiro de 1989 e junho de 1996. O critério de seleção e inclusão dos pacientes baseou-se na diferença de latência sensitiva = 1,0 ms entre os potenciais de ação sensitivos (PAS) dos nervos mediano e radial após estimulação simultânea no punho e registro no I dedo (diferença mediano-radial, DMR), representando diferença maior que 6 desvios-padrão (DP). DMR foi obtida em 125 mãos normais (grupo controle) com limite superior de normalidade de 0,43 ms (média + 2DP). Todos casos tiveram estudo eletrofisiológico bilateral, sendo excluídos casos com cirurgia prévia ou evidência de neuropatia periférica. A idade variou de 17 a 83 anos com média de 47,5 anos; 91,3 por cento eram do sexo feminino. Valor de DMR = 1,0 ms correlacionou-se em 95 por cento dos casos com latência distal motora do nervo mediano >4,25 ms (80 mm) e com latência distal sensitiva punho - II dedo = 3,01 ms (VC= 46,4 m/s), punho III dedo =3,14 ms (VC =44,6 m/s) e punho - IV dedo =3,26 ms (VC=42,9 m/s), todos com 140 mm de distância e latência medida no início do PAS. Os resultados estabelecem critérios anormais para o diagnóstico eletrofisiológico de STC em uma população brasileira para condução motora (latência distal motora do nervo mediano) e sensitiva (latência distal sensitiva do nervo mediano para dedos II, III e IV) após DMR =1,0 ms que indica diagnóstico seguro de STC em praticamente 100 por cento dos casos suspeitos.

Median nerve sep after a high medullary lesion: preserved N18 and absent P14 components. Case report

Median nerve SEPs recorded from patient with a high medullary lesion are described. The lesion involved the anteromedial and anterolateral right upper third of the medulla, as documented by MRI. Forty one days after the lesion, left median nerve SEP showed preserved N18 and absent P14 and N20 components; stimulation of the right median nerve evoked normal responses. These findings agree with the proposition that low medullary levels are involved in the generation of the N18 component of the median nerve SEP.

Duration of symptomatology and median segment sensory latency in 993 carpal tunnel syndrome hands (668 cases)

According to median sensory nerve action potential onset-latency to index finger in a 140 mm fixed distance, 993 carpal tunnel syndrome (CTS) hands from 668 patients were grouped into MIld (3.0 to 3.5 ms, 384 hands), MOderate (3.6 to 4.4 ms, 332 hands), SEvere (>4.4 ms, 135 hands) and Unrecordable (142 hands) and correlated with CTS symptomatology duration. All patients have sensory antidromic median-radial latency difference (MRD) e = 1.0 ms without any doubt CTS diagnosis. Patients with systemic disease, trauma or previous surgery were excluded. There is a remarkable cumulative percentage increase from 1 to 12 months in group UN (3.5 per cent to 38.7 per cent, 11 folds), much less than the group MI (13.8 per cent to 54.6 per cent, 3.9 folds). There is also a remarkable non-cumulative percentage increase in group UN, from 1 to 4-12 months; the group MI had a relatively uniform distribution in all symptomatic duration groups from 1 to > 60 months. The conclusion is that median nerve compression at carpal tunnel can lead to unrecordable potentials in a relatively short period from 1 to 12 months of evolution, suggesting acute/subacute deterioration. Eletrophysiological evaluation must be done periodically in patients that underwent clinical treatment, since cumulative 38.7 per cent of group UN was found in 12 months period.

Normative data of nerve conduction studies in the upper limb in Kuwait: are they different from the western data?

To establish the normal electrophysiological data for the median, ulnar and radial nerves and to compare our results with the Western data published in the literature. Nerve conduction studies were performed prospectively in the upper limbs of 50 carefully screened healthy individuals between the ages of 16 and 56 years using standardized technique. The median motor distal latency [DL] was 3.1 [0.3] ms, amplitude 11.01 [2.8] mV, conduction velocity [CV] 56.5 [3.5] m/s. The ulnar motor studies gave DL of 2.4 [0.3] ms, amplitude 9.2 [2.2] mV, CV 60.4 [5.0] m/s. Sensory studies for the median nerve were: DL of 2.3 [0.3] ms, amplitude 63.3 [18.9] micro V for men and 79.3 [28.8] micro V for women and CV 56.6 [7.6] m/s. For the ulnar nerve [DL] 2.0 [0.23] ms, amplitude 54.5 [18.4] micro V for men and 63.9 [16.8] micro V for women and CV 51.7 [5.3] m/s. The radial sensory studies were DL 1.95 [0.3] ms, amplitude 18.7 [5.5] micro V and CV 52.3 ms. Only gender showed a statistically significant effect on the sensory nerve action potential for the median [p = 0.04] and ulnar nerves [p = 0.07]. Normative conduction parameters of commonly tested nerves in the upper limb were established in our EMG lab in Kuwait. The mean motor nerve conduction parameters for the median and ulnar nerves compare favourably with the existing literature data. However, for the sensory nerves, higher value for the nerve action potential amplitude was demonstrated in the study. Gender was shown to have a significant effect on the sensory amplitude of the median and ulnar nerves

Normal median near nerve potential

In routine studies of sensory nerve conduction, only fibers 37 mum in diameter are analyzed. The late components which originate from thinner fibers are not detected. This explains why a normal sensory action potential (SAP) may be recorded in patients with peripheral neuropathies and sensory loss. In the present study we investigated the late component of the median SAP with a near nerve needle electrode technique in 14 normal volunteers (7 men and 7 women), aged 34.5 + 14.8 years. The stimulus consisted of rectangular pluses of 0.2-ms duration at a frequency of 1 Hz with an intensity at least 6 times greater than the threshold value for the main component. Five hundred to 2000 sweep averagings were performed. The duration of analysis was 40 or 50 ms and the wave analysis frequency was 200 (-6 dB/oct) to 3000 Hz (-12 dB/oct). We used an apparatus with a two-channel amplifier system, 200 MW or more of entry impedance and a noise level of 0.7 muVrms or less. The main component mean amplitude, conduction velocity and lactency and the late component mean amplitude, conduction velocity and latency were respectively (mean + SD): 26.5 + 5.42 muV, 56.8 + 5.42 m/s, 3.01 + 0.31 ms, 0.12 + 0.04 muV, 16.4 + 2.95 m/s and 10.6 + 2.48 ms. More sophisticated equipment has an internal noise of 0.6 muVrms. These data demonstrate that the technique can now be employed study thin fiber neuropathies, like in leprosy, using commercial electromyographs, even in non-academic practices.

Efecto del incremento de temperatura, de la edad y del sexo sobre la velocidad de conducción nerviosa motora (VCNM) de los nervios mediano y ulnar en sujetos sanos / Effect of an increase in skin temperature, age and sex on the nerve conduction velocity (NCV) of the median and ulnar nerves of normal subjects

De los factores que afectan la velocidad de conducción nerviosa (VCN) se considera que los más importantes son la temperatura, la edad y, en menor grado, el sexo. Sin embargo, llama la atención el que en la práctica clínica no se tome en cuenta a la temperatura, lo cual nos da como resultado que muy probablemente se obtengan diagnósticos erróneos o no se detecten patologías. El objetivo del presente trabajo fue determinar el efecto del incremento de temperatura, de la edad y del sexo sobre la VCNM de los nervios Mediano y Ulnar (derechos e izquierdos) en sujetos sanos. Se midió la VCNM en los nervios Mediano (n=60) de 30 sujetos (14 hombres y 16 mujeres, Edad 19 a 33 a., promedio = 26.9 a.), a 30, 33 y 36ºC. Para ello, se registraron los potenciales provocados por estimulación distal y proximal en cada caso y se empleó un sistema de registro CADWELL 5200A con un programa para cálculo automatizado de la VCNM, siguiendo la técnica descrita por Johnson (1980). Para alcanzar las temperaturas establecidas en el sujeto, se utilizó un cuarto de temperatura controlada, midiéndose la temperatura a nivel de la piel durante cada registro mediante un termopar colocado en los bordes interno y externo del antebrazo. A los resultados obtenidos se les calculó la media aritmética, la desviación estándar y el error estándar, y se hizo un análisis de regresión con correlación de Pearson, además se aplicó la prueba ANOVA para grupos independientes, por edad y sexo. Los resultados demuestran que existe una relación lineal (r = 0.99) entre los incrementos de temperatura y la VCNM y al hacer la comparación entre los valores de VCNM obtenidos en cada una de las temperaturas estudiadas usando la prueba de ANOVA, se encontró que, en el segmento muñeca/codo, existe una diferencia estadísticamente significativa (P< 0.06), en tanto que en el segmento codo/punto de Erb la diferencia no fue significativa (P= 0.46). Por otro lado, no se encontró diferencia estadísticamante significativa en los valores de VCNM obtenidos con respecto a la edad (P = 0. 19 - 0. 87) y el sexo (P = 0. 08 - 0. 99). En base a los resultados, se concluye que: a. El incremento de temperatura produce un aumento en la VCNM. b. Existe una relación lineal entre el incremento de temperatura y la VCNM. c. las variaciones de VCNM están relacionadas con el segmento explorado. d. No existe diferencias estadísticamente significativa entre la VCNM y la edad y el sexo, en el rango de edad estudiado

Median nerve somatosensory evoked potentials correlation with physical parameters.

Somatosensory evoked potentials (SEPs) following median nerve stimulation of 25 medical students were recorded along with their height, age and upper limb length. Three major positive and negative peaks were recorded. P1 (16 msec), N1 (20 msec), P2 (28 msec), N2 (33 msec), P3 (43 msec), N3 (50 msec). Significant correlation (P value < 0.05) of N1 and P1 with height and limb length was observed. It is therefore suggested that studies involving SEPs must include physical parameters like age, height and limb length. Our future studies will indicate the accurate correction factor for these physical parameters.

Latencia distal, amplitud del potencial de acción sensitivo y velocidad de conducción sensitiva de los nervios mediano y cubital en personas adultas sanas / Distant latency, amplitude of the potential of sensitive action and velocity of sensitive conduction of the median nerve and ulnar nerve in sane adult

En el laboratorio de electrodiagnóstico del Servicio de Medicina Física y Rehabilitación del Hospital Central "Antonio María Pineda", se determinó la latencia distal, amplitud del potencial de acción sensitivo y velocidad de conducción sensitiva ortodrómica y antidrómica de los nervios medianos y cubital en 20 adultos sanos. Se exploraron 40 nervios mediano y 40 nervios cubital, utilizando una técnica sencilla. Se determinaron valores promedios y desviación estándar. Los valores obtenidos son considerados los adecuados; se encuentran dentro del rango de límites normales descritos en la literatura, y servirán para disponer de valores normales de referencia a ser usados en el laboratorio de electrofisiología del Servicio de Medicina Física y Rehabilitación al evaluar los nervios mediano y cubital.