Revised normative values for grip strength with the Jamar dynamometer

The Jamar dynamometer has been widely used in various chronic illnesses and has demonstrated its strength as a potential prognostic indicator. Various stratified normative values have been published using different methodologies, leading to conflicting results. No study used statistical techniques considering the non-Gaussian distribution of the obtained grip strength (GS) values. Jamar GS was assessed in 720 healthy participants, subdivided into seven age decade groups consisting of at least 50 men and 50 women each. Normative values (median and fifth values) were calculated using quantile regressions with restricted cubic spline functions on age. Possible confounding personal factors (hand dominance, length, weight, hobby, and job categorization) were examined. Clinically applicable revised normative values for the Jamar dynamometer, stratified for age and gender, are presented. Hand dominance had no influence. Other personal factors only minimally influenced final values. This study provides revised normative GS values for the Jamar dynamometer

Small fiber neuropathy in Fabry disease

Previous studies have explicitly shown that small nerve fibers are affected in Fabry disease which is assumed to cause the severe neuropathic pain that patients may have from childhood on. Neuropathic pain and small fiber neuropathy characteristics have therefore been considered as appropriate study endpoints in studies on the efficacy of enzyme replacement therapy. However, the relationship between small fiber neuropathy characteristics and pain, as well as the course of small fiber neuropathy in Fabry disease is still uncertain. In this article a comprehensive overview of the existing literature on small nerve fiber function and structure and the relationship with pain, age and disease severity is presented supplemented with data from the Dutch Fabry cohort, with the aim to identify consensus as well as controversies and to propose a hypothesis on the evolution of neuropathy in Fabry disease. (C) 2012 Elsevier Inc. All rights reserve

Intraepidermal nerve fiber density and its application in sarcoidosis

Background: Intraepidermal nerve fiber density (IENFD) is considered a good diagnostic tool for small fiber neuropathy (SFN). Objectives: To assess stratified normative values for IENFD and determine the reliability and validity of IENFD in sarcoidosis. Methods: IENFD was assessed in 188 healthy volunteers and 72 patients with sarcoidosis (n = 58 with SFN symptoms, n = 14 without SFN symptoms). Healthy controls were stratified (for age and sex), resulting image groups (20-29, 30-39, ... up to >= 70 years) containing at least 15 men and 15 women. A skin biopsy was taken in each participant 10 cm above the lateral malleolus and analyzed in accordance with the international guidelines using bright-field microscopy. Interobserver/intraobserver reliability of IENFD was examined. In the patients, a symptoms inventory questionnaire (SIQ; assessing SFN symptoms) and the Vickrey Peripheral Neuropathy Quality-of-Life Instrument-97 (PNQoL-97) were assessed to examine the discriminative ability of normative IENFD values. Results: There was a significant age-dependent decrease of IENFD values in healthy controls, with lower densities in men compared with women. Good interobserver/intraobserver reliability scores were obtained (kappa values >= 0.90). A total of 21 patients with sarcoidosis had a reduced IENFD score (<5th percentile; 19 [32.8%] in patients with SFN symptoms, 2 [14.3%] in patients without SFN symptoms). The validity of the normative IENFD values was demonstrated by distinguishing between the SIQ scores and various PNQoL-97 values for the different patient groups. Conclusion: This study provides clinically applicable distal intraepidermal nerve fiber density normative values, showing age-and sex-related differences. Neurology (R) 2009; 73: 1142-114

Revising two-point discrimination assessment in normal aging and in patients with polyneuropathies

Objectives: To revise the static and dynamic normative values for the two-point discrimination test and to examine its applicability and validity in patients with a polyneuropathy. Methods: Two-point discrimination threshold values were assessed in 427 healthy controls and 99 patients mildly affected by a polyneuropathy. The controls were divided into seven age groups ranging from 20-29, 30 39,..., up to 80 years and older; each group consisted of at least 30 men and 30 women. Two-point discrimination examination took place under standardised conditions on the index finger. Correlation studies were performed between the scores obtained and the values derived from the Weinstein Enhanced Sensory Test (WEST) and the arm grade of the Overall Disability SumScore (ODSS) in the patients' group (validity studies). Finally, the sensitivity to detect patients mildly affected by a polyneuropathy was evaluated for static and dynamic assessments. Results: There was a significant age-dependent increase in the two-point discrimination values. No significant gender difference was found. The dynamic threshold values were lower than the static scores. The two-point discrimination values obtained correlated significantly with the arm grade of the ODSS (static values: r = 0.33, p = 0.04; dynamic values: r = 0.37, p = 0.02) and the scores of the WEST in patients (static values: r = 0.58, p = 0.0001; dynamic values: r = 0.55, p = 0.0002). The sensitivity for the static and dynamic threshold values was 28% and 33%, respectively. Conclusion: This study provides age-related normative two-point discrimination threshold values using a two-point discriminator (an aesthesiometer). This easily applicable instrument could be used as part of a more extensive neurological sensory evaluation

Intraepidermal nerve fiber density at the distal leg: a worldwide normative reference study

The diagnostic reliability of skin biopsy in small fiber neuropathy depends on the availability of normative reference values. We performed a multicenter study to assess the normative values of intraepidermal nerve fiber (IENF) density at distal leg stratified by age deciles. Eight skin biopsy laboratories from Europe, USA, and Asia submitted eligible data. Inclusion criteria of raw data were healthy subjects 18 years or older; known age and gender; 3-mm skin biopsy performed 10-cm above the lateral malleolus; bright-field immunohistochemistry protocol, and quantification of linear IENF density in three 50-mu m sections according to published guidelines. Data on height and weight were recorded, and body mass index (BMI) was calculated in subjects with both available data. Normative IENF density reference values were calculated through quantile regression analysis; influence of height, weight, or BMI was determined by regression analyses. IENF densities from 550 participants (285 women, 265 men) were pooled. We found a significant age-dependent decrease of IENF density in both genders (women p < 0.001; men p = 0.002). Height, weight, or BMI did not influence the calculated 5th percentile IENF normative densities in both genders. Our study provides IENF density normative reference values at the distal leg to be used in clinical practice

Contact heat evoked potentials: Normal values and use in small-fiber neuropathy

Introduction: Contact heat evoked potentials (CHEPs) may be an objective, non-invasive diagnostic tool in small-fiber neuropathy (SFN). This study establishes normal CHEP values and examines their applicability in SFN patients. Methods: Standardized CHEPs were administered at the wrist and ankle. The N2 and P2 latencies and N2-P2 peak-peak amplitude were recorded by electroencephalography. We examined healthy subjects (n=97), stratified by age and gender, and SFN patients with abnormal intraepidermal nerve fiber density (n=42). CHEP reproducibility and interobserver values were also investigated. Results: CHEP normative values were determined. There was a 9-16% increase in latency per centimeter of height with increasing age. Amplitudes were higher in women than men, and decreased (17-71%) with aging. Test-retest reproducibility and interobserver values were >0.61 and >0.96, respectively. CHEPs were abnormal in 73.8% of the patients. Conclusion: In this study we have established normal values, reliability, and clinical applicability of CHEPs in SFN

Grip strength comparison in immune-mediated neuropathies: Vigorimeter vs. Jamar

The Jamar dynamometer and Vigorimeter have been used to assess grip strength in immune-mediated neuropathies, but have never been compared to each other. Therefore, we performed a comparison study between these two devices in patients with immune-mediated neuropathies. Grip strength data were collected in 102 cross-sectional stable and 163 longitudinal (new diagnoses or changing condition) patients with Guillain-Barre syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), gammopathy-related polyneuropathy (MGUSP), and multifocal motor neuropathy (MMN). Stable patients were assessed twice (validity/reliability studies). Longitudinal patients were assessed 3-5times during 1year. Responsiveness comparison between the two tools was examined using combined anchor-/distribution-based minimum clinically important difference (MCID) techniques. Patients were asked to indicate their preference for the Jamar or Vigorimeter. Both tools correlated highly with each other (=0.86, p<0.0001) and showed good intra-class correlation coefficients (Jamar [Right/Left hands]: ICC 0.997/0.96; Vigori: ICC 0.95/0.98). Meaningful changes were comparable between the two instruments, being higher in GBS compared to CIDP patients. In MGUSP/MMN poor responsiveness was seen. Significant more patients preferred the Vigorimeter. In conclusion, validity, reliability, and responsiveness aspects were comparable between the Jamar dynamometer and Vigorimeter. However, based on patients' preference, the Vigorimeter is recommended in future studies in immune-mediated neuropathies