Electrophysiological Study of the Tibial Nerve Across the Tarsal Tunnel in Distal Symmetric Diabetic Polyneuropathy.

OBJECTIVE: The aim of the study was to demonstrate abnormalities of motor conduction of the tibial nerve across the tarsal tunnel in type 2 diabetes. DESIGN: One hundred twenty-four consecutive patients (mean age = 66.6 yrs, 62.1% male) with distal symmetric diabetic polyneuropathy clinically diagnosed were prospectively enrolled. Nerve conduction studies of deep peroneal, tibial, superficial peroneal, medial plantar, and sural nerves and standard needle electromyography in the lower limbs were performed. Demographic, anthropometric, and clinical findings were collected. RESULTS: Motor conduction velocity of the tibial nerve across tarsal tunnel was slowed in 60.5% of patients; another 4% showed conduction block across tarsal tunnel without reduction of motor conduction velocity. Overall percentage of abnormalities across tarsal tunnel (64.5%) exceeds that of the sensory conduction velocities of proximal sural and superficial peroneal nerves. Abnormal tibial motor conduction velocity across tarsal tunnel represents the most common abnormality among all motor nerve conduction study parameters and significantly correlates with hemoglobin level, diabetic neuropathic index score, and diabetic complications frequency. CONCLUSIONS: Tibial conduction abnormalities across tarsal tunnel are the most sensitive motor parameter in distal symmetric diabetic polyneuropathy, second only to conduction abnormalities of sensory/mixed distal nerves of the feet. The use of nerve conduction studies across tarsal tunnel of the tibial nerve may be useful in the electrophysiological protocol to confirm the diagnosis of distal symmetric diabetic polyneuropathy.

Cutaneous silent period in ulnar neuropathy at the elbow.

INTRODUCTION/AIMS: The cutaneous silent period (CSP) reflects the function of A-delta sensory fibers. There are few studies on CSP in nerve entrapment syndromes. This study aims to evaluate the neurophysiological abnormalities of small-diameter sensory fibers in ulnar neuropathy at the elbow (UNE) by means of CSP. METHODS: We consecutively evaluated UNE patients at one electrodiagnostic laboratory. The CSP was obtained upon stimulating the fifth (D5) and third digits, recording from the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles. RESULTS: We enrolled 37 UNE patients (mean age 55.4 ± 11.2 y) and 30 controls (mean age 51.2 ± 11.1 y). The combinations of the D5-APB and D5-FDI mean onset latencies of CSP were significantly more prolonged in patients (83.7 ± 6.8 and 84.5 ± 8 ms, respectively) than in controls (78.2 ± 8.1 and 79.4 ± 7.6 ms, respectively). The D5-FDI duration of CSP was shorter in patients (52.2 ± 8.3 ms) than in controls (55.8 ± 7 ms). The mean of the onset latencies of D5-FDI and D5-APB was related to the clinical severity (P = .013 and .0025, respectively). D5-APB and D5-FDI onset latencies were more prolonged and the duration was shorter in the UNE group with absent ulnar sensory nerve action potentials (SNAPs) and axonal motor damage than in patients with preserved SNAPs and with demyelinating damage. DISCUSSION: CSP was able to demonstrate abnormalities of small-diameter myelinated sensory fibers. This damage was directly related to UNE severity and to axonal damage of motor fibers. Absence of a sensory large-diameter fiber response did not exclude preserved residual small fiber conduction.

Sympathetic Skin Response in Ulnar Neuropathy at the Elbow.

INTRODUCTION: The sympathetic skin response (SSR) reflects the function of sudomotor sympathetic unmyelinated fibers. This study evaluates SSR abnormalities in ulnar neuropathy at the elbow (UNE). METHODS: Sympathetic skin response was obtained after electrical stimulation of the glabella recording simultaneously from the hand palm (P), third digit (M3) and fifth digit ipsilateral (U5) and contralateral (cU5) to the side of UNE. Ten consecutive SSRs were recorded from each recording side of all participants. RESULTS: The authors enrolled 31 patients (mean age 54.3 ± 11.4 years) and 25 subjects of a control group (mean age 52.6 ± 11.3 years). The mean of the areas and the area of the largest response of U5-SSR were significantly lower in the patients (106.9 ± 68.9 and 127.8 ± 79.7 µV/s, respectively) than in control group (161.8 ± 116.6 and 197.2 ± 143.3 µV/s, respectively) and in the affected than in the unaffected sides of the patients (155.3 ± 84.8 and 197.7 ± 103.3 µV/s, respectively); there were no differences in U5-SSR latencies and P-SSR and M3-SSR parameters. U5-SSR mean areas and U5-SSR largest area were reduced in 29% and 26% of patients, respectively. The differences between patients and control group and the number of patients with U5-SSR abnormalities increased when the ratios of M3/U5-SSR and U5/cU5-SSR areas were considered. U5-SSR area was related to UNE clinical severity and to some parameters of the ulnar nerve conduction velocity and cutaneous silent period. CONCLUSIONS: Sympathetic skin response is useful to demonstrate abnormalities of sympathetic fibers even if UNE patients do not complain for sympathetic symptoms. The SSR abnormalities were evident only if electrophysiological damage of myelinated fibers was moderate or severe.

Comorbidities, anthropometric, demographic, and lifestyle risk factors for ulnar neuropathy at the elbow: A case control study.

We performed a prospective multicenter case-control study to explore the association between ulnar neuropathy at elbow (UNE) and body and elbow anthropometric measures, demographic and lifestyle factors, and comorbidities. Cases and controls were consecutively enrolled among subjects admitted to four electromyography labs. UNE diagnosis was made on clinical and neurographic findings. The control group included all other subjects without signs/symptoms of ulnar neuropathy and with normal ulnar nerve neurography. Anthropometric measurements included weight, height, waist, hip circumferences, and external measures of elbow using a caliper. The participants filled in a self-administered questionnaire on personal characteristics, lifestyle factors, and medical history. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) by fitting unconditional logistic regression models adjusted by center and education level. We enrolled 220 cases (males 61.8%; mean age 51.7 years) and 460 controls (47.4% males; mean age 47.8 years). At multivariable analysis, UNE was associated to male gender (OR = 2.4, 95%CI = 1.6-3.7), smoking habits (>25 pack-years (OR = 2.3, 95%CI = 1.3-4.1), body mass index (OR = 1.05, 95%CI 1.01-1.10), polyneuropathies (OR = 4.1, 95%CI 1.5-11.5), and leaning with flexed elbow on a table/desk (OR = 1.5, 95%CI 1.0-2.2). Cubital groove width (CGW) turned out to be negatively associated with UNE (OR = 0.80, 95%CI = 0.74-0.85). Our study suggests that some personal factors especially anthropometric measures of the elbow may play a role in UNE pathogenesis as the measures of wrist in CTS. We demonstrated that for each millimeter of smaller CGW the risk of idiopathic UNE increases of 25%.

The effects of anthropometric and demographic factors on conduction parameters of the ulnar nerve: Multivariate analysis.

The objective of the study is to investigate the effects of age, height, gender, body mass index (BMI), waist-to-hip ratio (WHR), arm and elbow measures on ulnar nerve conduction. We enrolled 261 "disease-free" subjects. We analyzed motor conduction velocity (MCV) in across elbow (AE) and forearm tracts, and sensory conduction velocity in 4th, 5th digit-wrist tracts (U4, U5) and in dorsal ulnar cutaneous nerve (DUC). We calculated the amplitudes of sensory and motor potentials (CMAPa and SNAPa), % of CMAPa drop AE, MCV drop and distal motor latency (DML). Univariate and multivariate analyses were performed. We estimated the predictive equations. The median nerve was examined for comparison. Age was negatively correlated with all conduction parameters. Forearm and AE MCV, % of CMAPa drop, DML, U4 and U5 SCV also depended upon height. Females had higher U4 and U5 SNAPa than males. BMI showed inverse relationship with U4 and U5 SNAPa. DUC parameters depended upon BMI and arm length. Similar trends were observed for the median nerve. "Normative" ulnar conduction parameters should be adjusted for demographic and anthropometric measures to improve diagnostic sensitivity.

Clinical Findings and Electrodiagnostic Testing in Ulnar Neuropathy at the Elbow and Differences According to Site and Type of Nerve Damage.

OBJECTIVE: The aim of the study was to evaluate the clinical and electrodiagnostic testing in ulnar neuropathy at the elbow and differences according to site (humeroulnar arcade vs. retroepicondylar groove) and injury physiopathology (axonal vs. demyelinating), through prospective multicenter case-control study. DESIGN: Cases and controls were matched by age and sex. Ulnar neuropathy at the elbow diagnosis was made on symptoms. Statistical analysis was performed using Mann-Whitney, χ, and analysis of variance tests. RESULTS: One hundred forty-four cases and 144 controls were enrolled. Sensory loss in the fifth finger had the highest sensitivity (70.8%) compared with clinical findings. Motor conduction velocity across elbow reached the highest sensitivity (84.7%) in localizing ulnar neuropathy at the elbow recording from at least one of the two hand muscles (first dorsal interosseous and abductor digiti minimi). Abnormal sensory action potential amplitude from the fifth finger occurred more frequently in axonal than in demyelinating forms. Differences between retroepicondylar groove and humeroulnar arcade regarded conduction block and job type. CONCLUSIONS: Clinical findings have less usefulness than electrodiagnostic testing in ulnar neuropathy at the elbow diagnosis. Motor conduction velocity across elbow recorded from both abductor digiti minimi and first dorsal interosseous increases diagnostic accuracy. Axonal forms have greater clinical and electrodiagnostic testing severity than demyelinating forms, which are more frequent in retroepicondylar groove. Manual workers prevailed in humeroulnar arcade. These findings may be helpful in prognostic and therapeutic approaches.

The external elbow measure as surrogate of the anatomical width of cubital groove and possible risk factor of ulnar neuropathy at the elbow.

Introduction: There are no studies on elbow anthropometry in ulnar neuropathy at the elbow (UNE). We aimed to test the interrater agreement of external elbow measurements with caliper, the matching of external width of cubital groove (WCG) measures with those obtained through conventional radiography (XR) and ultrasonography (US). The final aim was to evaluate the differences of anthropometric elbow and body measures between UNE cases and controls with multicenter prospective study.Materials and methods: After common training of five observers for external elbow and body anthropometric measurements, we assessed the interrater agreement of measures in a single blind measurement session in 16 healthy volunteers. Then we verified if external WCG measures in eight and four of the above 16 subjects matched with those obtained with US and XR. Finally, we enrolled 40 consecutive idiopathic UNE cases in four electromyographic labs matched for sex and age with 40 controls to evaluate the differences of anthropometric measures.Results: There was high interrater agreement of all anthropometric body and elbow measures (Kendal's and interclass correlation coefficients between 0.84 and >0.9). We found high relations between WCG caliper measures and those obtained with US and XR (r > 0.9). WCG was smaller in cases than in controls (13.2 vs.15.7 mm, p < 0.001). There were no differences in body anthropometric measures (BMI and waist-to-hip ratio).Conclusion: The external measurement of WCG is reliable and reproducible and may be risk factor of UNE. Future studies should be performed in lager samples evaluating the relations with lifestyle and occupational factors.

Diagnostic Accuracy of Sensory Clinical Findings of the Hand Dorsum and of Neurography of the Dorsal Ulnar Cutaneous Nerve in Ulnar Neuropathy at the Elbow.

OBJECTIVE: The main objective is to investigate the diagnostic accuracy and the relation of touch sensation and subjective sensory symptoms in the medial aspect of the hand dorsum, and neurography of the dorsal ulnar cutaneous nerve (DUCN) in ulnar neuropathy at the elbow (UNE). Secondary objective is to report the electrophysiological occurrence of anatomical variant of sensory innervation of the medial aspect of the hand dorsum from superficial radial nerve (SRN). DESIGN: Prospective, cohort study. SETTING: Electromyography laboratory. PARTICIPANTS: Consecutive participants (N=282), those with UNE (n=81) and those without UNE (n=201), were enrolled. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Accuracy and agreement between sensory clinical findings of the medial hand dorsum and neurography of DUCN in UNE diagnosis. RESULTS: DUCN neurographic and sensory findings had high specificity and relatively low sensitivity. Normal or abnormal sensory nerve action potential (SNAP) of DUCN matched with normal or abnormal touch sensation of the medial aspect of hand dorsum. Abnormal DUCN SNAP was related to the clinical severity of UNE and to the axonal damage of the ulnar nerve. Anatomical variant of the innervation of hand dorsum from SRN was demonstrated in 31 of 564 hands (6.2%) belonging to 26 of 282 participants (9.2%). If the variant was present, DUCN SNAP of the same side was more frequently absent or of low amplitude. CONCLUSIONS: The utility of DUCN neurography and sensory findings of the medial aspect of the dorsum of the hand is limited in the diagnosis of UNE. However, if DUCN SNAP is absent or low in amplitude, it is advisable to check the presence of the anatomical variant of the innervation of the medial aspect of the hand dorsum from SRN.

Relations between sensory symptoms, touch sensation, and sensory neurography in the assessment of the ulnar neuropathy at the elbow.

OBJECTIVES: To evaluate sensitivity, specificity and predictive values of sensory findings in ulnar neuropathy at the elbow (UNE), differences according to UNE localization and pathophysiology, and relation between the sites of sensory symptoms, abnormal evaluation of sensation and neurographic findings of ulnar sensory nerve. METHODS: Hand diagram and Semmes-Weinstein monofilaments were used for clinical evaluation in four ulnar hand territories. Sensory neurography was measured in the fourth and fifth digits-wrist segments (U5) and in the dorsal ulnar cutaneous nerve. RESULTS: We enrolled 75 idiopathic UNE cases and 180 controls. Symptoms in the fifth digit, reduction of touch sensation and U5 sensory nerve action potential amplitude (SNAPa) had the highest sensitivity, specificity and predictivity in UNE diagnosis. The normal/abnormal sensory clinical findings of the fifth digit matched with normal/abnormal U5 SNAP more than the matching of sensory parameters in the other ulnar hand sites. Sensory anomalies were more frequent in predominantly axonal than demyelinating UNE. There were no differences according to UNE location. CONCLUSION: Sensory anomalies of the fifth digit are constant findings in UNE more than anomalies of the other ulnar nerve hand regions. SIGNIFICANCE: Probably the fascicles from fifth digit are the most liable to damage at elbow.

Severity of Carpal Tunnel Syndrome and Diagnostic Accuracy of Hand and Body Anthropometric Measures.

OBJECTIVE: To study the diagnostic properties of hand/wrist and body measures according to validated clinical and electrophysiological carpal tunnel syndrome (CTS) severity scales. METHODS: We performed a prospective case-control study. For each case, two controls were enrolled. Two five-stage clinical and electrophysiological scales were used to evaluate CTS severity. Anthropometric measurements were collected and obesity indicators and hand/wrist ratios were calculated. Area under the receiver operating characteristic curves (AUC), sensitivity, specificity, and likelihood ratios were calculated separately by gender. RESULTS: We consecutively enrolled 370 cases and 747 controls. The wrist-palm ratio, waist-hip-height ratio and waist-stature ratio showed the highest proportion of cases with abnormal values in the severe stages of CTS for clinical and electrophysiological severity scales in both genders. Accuracy tended to increase with CTS severity for females and males. In severe stage, most of the indexes presented moderate accuracy in both genders. Among subjects with severe CTS, the wrist-palm ratio presented the highest AUC for hand measures in the clinical and electrophysiological severity scales both in females (AUC 0.83 and 0.76, respectively) and males (AUC 0.91 and 0.82, respectively). Among subjects with severe CTS, the waist-stature ratio showed the highest AUC for body measures in the clinical and electrophysiological severity scales both in females (AUC 0.78 and 0.77, respectively) and males (AUC 0.84 and 0.76, respectively). The results of waist-hip-height ratio AUC were similar. CONCLUSIONS: Wrist-palm ratio, waist-hip-height ratio and waist-stature ratio could contribute to support the diagnostic hypothesis of severe CTS that however has to be confirmed by nerve conduction study.

Associations Between Body Anthropometric Measures and Severity of Carpal Tunnel Syndrome.

OBJECTIVE: To assess the associations between carpal tunnel syndrome (CTS) severity and selected anthropometric and obesity indexes. DESIGN: We performed a case-control study. Clinical and electrophysiological severity of CTS was classified as mild, moderate, or severe based on validated scales. Body and hand anthropometric characteristics were measured at the time of the electrodiagnostic study. We estimated the relative risk ratios (RRRs) of CTS severity by fitting multinomial logistic regression models adjusted by age and sex. In addition, we fitted multivariable models, including age, sex, wrist ratio, hand ratio, body mass index (BMI), and waist/stature ratio. SETTING: Electromyography laboratories. PARTICIPANTS: Consecutive patients (N=1087), those with CTS (n=340) and those without CTS (n=747), were enrolled. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Associations between CTS severity and selected anthropometric and obesity indexes. RESULTS: We observed associations between many anthropometric indexes and CTS severity. Among obesity indexes, the waist/stature ratio, and among hand anthropometric indexes, the wrist/palm ratio, showed the highest RRRs for the clinical and electrophysiological severity scales. The RRRs of severe CTS (adjusted for age and sex) for the wrist/palm ratio were 3.5 for the clinical scale and 2.4 for the electrophysiological scale. The RRRs of severe CTS for the waist/stature ratio were 2.3 for the clinical scale and 2.0 for the electrophysiological scale. In the multivariable models, both BMI and the waist/stature ratio were associated with the outcomes. CONCLUSIONS: Different configurations of the body and, in particular, the hand and wrist system may influence the occurrence and severity of CTS. Multiple obesity indexes, possibly including the waist/stature ratio, should be considered when investigating the association between body composition and CTS. Future studies should determine whether in obese subjects with CTS the weight and waist circumference loss produces an improvement in CTS symptoms and recovery of distal conduction velocity of the median nerve.

Low sensitivity of F-wave in the electrodiagnosis of carpal tunnel syndrome.

OBJECTIVE: Previous studies showed "F-wave inversion" (F-INV) as a sensitive method in the electrodiagnosis of early stage of carpal tunnel syndrome (CTS). This study aimed at evaluating the sensitivity and specificity of F-wave and nerve conduction velocity (NCV) testing in CTS. METHODS: We consecutively enrolled 244 cases and 108 controls. F-waves analysis included: Fwave minimum and mean latencies, F-wave persistence and chronodispersion, mean-F/CMAP amplitude ratio, F-INV. Specificity and sensitivity of F-waves parameters were calculated in the whole sample of CTS patients and by grouping the patients according to CTS severity. Multivariate logistic regression was also performed using F-INV as a dependent variable. RESULTS: In the whole sample the sensitivity of F-mean-INV and of median-ulnar NCV comparative testing was 50.8% and 93.7%, respectively. F-INV sensitivity dropped to 8% in CTS early stage. F-INV could be predicted only by distal motor latency of the median nerve. The sensitivity of all F-wave parameters increased only in the most severe stages of CTS. CONCLUSIONS: This study does not confirm the electrodiagnostic usefulness of F-INV in early stage of CTS. All F-wave parameters, including F-INV, are much less sensitive than conventional NCV in CTS electrodiagnosis. F-wave does not add further useful information specifically related to CTS.

Anthropometric measurements as a screening test for carpal tunnel syndrome: receiver operating characteristic curves and accuracy.

OBJECTIVE: To identify optimal cutoff values for body, hand, and wrist measurements in order to correctly identify individuals with carpal tunnel syndrome (CTS), using receiver operating characteristic (ROC) curves. METHODS: We enrolled patients with CTS and control subjects at a 1:2 ratio, regardless of age and sex. The diagnosis of CTS was based on clinical findings and delayed distal conduction velocity of the median nerve. The anthropometric measurements included weight, height, waist circumference, hip circumferences, wrist depth/width, third digit length, and palm length/width. Obesity indicators and hand/wrist ratios were calculated. Area under the ROC curve (AUC), sensitivity, specificity, and likelihood ratios were calculated separately according to sex. To assess the role of multiple anthropometric measurements, we fit multivariable logistic regression models including age, wrist ratio, shape index, body mass index, and waist-to-hip ratio. RESULTS: The study group comprised 1,117 subjects (250 female patients and 474 female controls; 120 male patients and 273 male controls). In women, the accuracy of all anthropometric measures was low (AUC ≤0.64). In men, the accuracy of the hand ratio, shape index, and wrist-to-palm ratio was moderate (AUC = 0.75). The estimates from the multivariable models confirmed the well-known associations between the selected variables and the risk of CTS, but the use of multiple predictors did not dramatically improve the diagnostic performance observed for single anthropometric indexes. CONCLUSION: In clinical practice, the cutoff values for many anthropometric measurements have limited value as tools for the diagnosis of CTS.

Knowledge of electromyography (EMG) in patients undergoing EMG examinations.

The aim of this study was to evaluate knowledge of electromyography (EMG) in patients undergoing the procedure. In one year, 1,586 consecutive patients (mean age 56 years; 58.8% women) were admitted to two EMG labs to undergo EMG for the first time. The patients found to be "informed" about the how an EMG examination is performed and about the purpose of EMG numbered 448 (28.2%), while those found to be "informed" only about the manner of its execution or only about its purpose numbered 161 (10.2%) and 151 (9.5%), respectively. The remaining 826 (52.1%) patients had either no information, or the information they had was very poor or incorrect (this was particularly true if they had been consulting websites). Being "informed" was associated with level of education (high), type of referring physician (specialist) and with an appropriate referral diagnosis specified in the EMG request. The quality of patient information on EMG was found to be very poor and could be improved. Physicians referring patients for EMG examinations, especially general practitioners, should assume primary responsibility for patient education and counseling in this field.

Waist circumference and waist-to-hip ratio in carpal tunnel syndrome: a case-control study.

BACKGROUND: The association between carpal tunnel syndrome (CTS) and high body mass index (BMI) and some hand measures is well known. No study has been specifically focused on waist circumference (WC) and waist-to-hip-ratio (WHR). The aim of this prospective case-control study is to evaluate the association between CTS and WC, WHR and other body and hand anthropometric measures. METHODS: We consecutively enrolled one "idiopathic" CTS case for two controls in 3 outpatient electromyography labs. The main anthropometric measures were BMI, WC, WHR, wrist ratio (WR) and hand ratio (HR). We performed univariate and multivariate analyses. RESULTS: Female cases and controls were 250 and 474 and male cases and controls were 120 and 273, respectively. At univariate analysis there were differences in many anthropometric measures between cases and controls. At multivariate logistic regression analyses high BMI, WC and WHR and abnormal HR and WR were independent risk factors for CTS. Crossing two categories between BMI, WC and WHR, the overweight subjects, especially females, were at risk only if they had very high WC or high WHR. The risk increased if they were obese. CONCLUSIONS: High WC/WHR doubles the risk of CTS, the risk further increased if overweight/obese subjects have also very high WC or high WHR. The obese subjects were always at risk regardless of WC and WHR values. Metabolic causes of this association with CTS were hypothesised. BMI is not the only and most powerful body predictor of "idiopathic" CTS, but also WHR and WC should be considered. These measures may not be interchangeable and it may be desirable to consider the utility of their joint use.

Requests of electrodiagnostic testing: consistency and agreement of referral diagnosis. What is changed in a primary outpatient EMG lab 16 years later?

The aims are to evaluate electrodiagnostic testing (EDX) requests and verify if presence, consistency and agreement of referral diagnosis could be predicted by patient demographic findings and referring physician typology, and if there were differences in respect to our previous study performed 16 years ago. The study concerns EDX requests referred to two electromyography labs during the year 2011. Differences between findings of general practitioners (GPs) versus specialists' requests and between this study with the previous were assessed. Multivariate logistic regression was performed to calculate odds ratio to assess the strength of association between presence, consistency and agreement of referral diagnosis with patient demographic findings and referring physician typology. We evaluated EDX requests of 1,586 patients (mean age 56 ± 16.7 years, 58.8 % women), 1,050 (66.2 %) were referred by GPs and 536 (33.8 %) by specialists. The suspected diagnosis was reported in 1,033 (65.1 %) requests, the overall consistency was 79.9 % and agreement was 71.9 %. Presence, consistency and agreement of referral diagnosis were predicted by physician's typology (specialist). Only if the suspected diagnosis was carpal tunnel syndrome, consistency and agreement were high regardless of doctor's typology. The physicians, especially GPs, who reported the referral diagnosis decreased during the past 16 years. A diagnostic test, including EDX, should be considered mainly if it fits into the best diagnostic strategy. The neurophysiologist should decide if EDX is useful, make the best decision on further management, and not submit patients to unnecessary and uncomfortable procedures. This choice of behaviour could be questionable and may lead to ethical and deontological problems.

Predictive factors of recovery in long thoracic mononeuropathy.

The aim of the study was to identify specific factors that affect the outcome in patients with long thoracic mononeuropathy. The authors reviewed all medical records of patients with long thoracic mononeuropathy from the archive of the electromyography service over the past 16 years. Age, sex, occupation, pain at onset, symptom duration, neuropathy causes and side, and electromyography findings were collected. The outcome was evaluated by performing standard telephone interviews consisting of 9 queries about use limitations in the affected upper limb. If no limitation existed, the recovery was considered complete. If partial limitations only affected the upper limb in performing 5 or fewer of 9 specific activities, the outcome was considered good; if limitations affected more than 5 activities, the outcome was considered poor. The authors performed a multivariate logistic regression to calculate the association between good outcome or full recovery and poor outcome with demographic, clinical, and electromyography findings. Forty-one patients were included (mean±SD age, 39±14 years; 68.3% men). Causes were shoulder-arm overuse or trauma in 19 patients, iatrogenic in 5, idiopathic in 9, and inflammatory in 8. Twenty-seven patients had a good outcome and full recovery and 14 had a poor outcome. No patient underwent surgery. Age, sex, occupation, pain at onset, symptom duration, neuropathy side, and electromyography findings were not predictive of the outcome. The probability of full recovery and good outcome was 7.5 times greater in long thoracic mononeuropathy secondary to idiopathic or inflammatory causes compared with other etiologies.

Sympathetic skin response. Glabella stimulation may be more useful than peripheral nerve stimulation in clinical practice.

The aim is to verify whether glabella electrical stimulation evokes sympathetic skin responses (SSR) without inter-side differences in latency and area of the responses and is more useful in mononeuropathies than peripheral nerve stimulation. SSRs were recorded in 25 healthy subjects from right palm, third (M3SSR) and fifth fingers and contralateral third finger. The inter-side differences of grand mean area and mean of largest area of M3SSR were significant only by ulnar nerve and not by glabella stimulation. Therefore glabella stimulation may be used in mononeuropathies comparing SSR area recorded from affected side with respect to contralateral healthy side.

Thenar motor neuropathy electrophysiological study of 28 cases.

PURPOSE: To report an electrophysiological study on thenar motor neuropathy of the median nerve. METHODS: Twenty-eight consecutive patients (mean age, 48.8 years; 17 men) with dominant hand thenar muscle weakness without sensory symptoms were enrolled in this study. Electromyography of hand and forearm muscles and neurography of median, ulnar, radial, and palmar nerves, including distal motor latency recording from the second interosseous-lumbrical muscles, were performed. RESULTS: Complete denervation of the abductor pollicis brevis muscle was observed in one case and delayed median abductor pollicis brevis-distal motor latency was observed in the others. Other neurographic findings were normal. CONCLUSIONS: Thenar motor neuropathy may have different pathogeneses. It may be considered a variant of carpal tunnel syndrome involving the motor branch only or more likely due to chronic direct compression of the branch, because it preferentially affects males, dominant hand, and persons doing manual work. In both cases, anatomic origin and variations in the course of the branch may favor thenar motor neuropathy.

Sympathetic skin response in primary Raynaud's phenomenon.

OBJECTIVES: The pathogenetic hypotheses of Raynaud's phenomenon include increased activation of sympathetic noradrenergic nerves controlling muscle tone of digit arteriolar walls. Because acral sympathetic fibres contain vasoactive adrenergic and cholinergic fibres for sweat glands, we tested cholinergic sympathetic fibre function in primary Raynaud's phenomenon (PRP) patients by sympathetic skin response (SSR). METHODS: Twenty-six consecutive patients (19 women, 7 men, mean age 37.8 years) with PRP were enroled prospectively. SSR was obtained by random electrical stimulation of the left ulnar nerve at the wrist recording from the palm (PSSR), third (M3SSR) and fifth fingers (U5SSR) on the right side. For each subject latency of shortest response, area of largest response and grand mean latencies and areas of 12 consecutive responses were calculated. The differences between patients and a control group (15 women, 6 men, mean age 38.9 years) were calculated. SSR habituation was also compared between patients and controls. RESULTS: PSSRs were recorded in all patients and no difference in any PSSR parameter was found between patients and controls. U5SSRs and M3SSRs were absent in two patients. Grand mean area and mean of largest M3SSRs and U5SSRs were significantly lower in patients than in controls. Grand mean latency and mean of shortest M3SSRs and U5SSRs were significantly slower in patients than in controls. M3 and U5SSRs habituated less in patients than in controls. INTERPRETATION: Dysregulation of cholinergic sympathetic fibres innervating the fingers was found in PRP. Abnormal peripheral mechanisms may be the cause. Since SSR habituation was also not normal, even central mechanisms may be implicated.