Ensuring inter-tester reliability of voluntary muscle and monofilament sensory testing in the INFIR Cohort Study.

OBJECTIVE: To assess the reliability of monofilament (MF) and voluntary muscle strength (VMT) testing carried out by nine physiotherapy staff recruited for the ILEP Nerve Function Impairment & Reaction (INFIR) Cohort Study in India. DESIGN: A multiple pair inter-tester reliability study was carried out in Uttar Pradesh, India. Newly trained testers were paired up with an experienced physiotherapist, whose assessment served as the gold standard. Each pair completed a series of assessments. All testers had undertaken a week of specific VMT and MF training, followed by a month of practice in the hospital setting. Reliability was assessed by calculating weighted Kappa (Kw) statistics, which may be interpreted as the chance-corrected proportion of agreement between testers. RESULTS: Eight newly-trained physiotherapists and one physiotechnician took part in the study. In the early stages of the study some areas of weak agreement were identified and correct assessment technique was reviewed, particularly for the eye. Good to very good reliability (Kw 0.62 to 0.99) was found for all sensory tests and most muscle strength tests. The only lower Kw scores (0-48 to 0-59, suggesting only moderate reliability) were for the VMT of muscles supplied by the median nerve in one of the study's two field centres. Even in this case, testers never varied by more than one grade, but calculation of Kw was negatively influenced by a lack of variation among the subjects. In addition, testers never varied by more than one grade from the gold standard. CONCLUSION: Even though all testers were professionally trained and received additional specific training and practice in MF and VMT testing, discrepancies in technique required an early review and correction. This fact highlights the need for careful training and formal reliability testing. This should extend to referral centres where staff are involved in assessing the symptoms of reaction and monitoring response to treatment. Reliability testing provides the opportunity to address important discrepancies in technique that may persist even in the presence of protocols and qualified and trained staff. It is therefore a valuable tool as part of a training procedure for situations, where patients may be assessed by different testers. Overall, our results were deemed good enough to proceed with the INFIR study, using VMT and MF testing as a baseline against which to compare more sophisticated methods of nerve function testing.

El estudio de Cohortes Infir: evaluación de la neuropatía sensitiva y motora en la lepra / No disponible

Objetivo: Comparar los distintos métodos para detector la neuropatía periférica en la lepra y evaluar la validez de la prueba de monofilamente (MF) y la técnica del músculo voluntario (VMT) como pruebas estándar de la función neural. Diseño: Un estudio multicéntrico de 303 pacientes de lepra multibacillar (MB). Métodos: Se dieron de alta en el estudio nuevos pacientes MB que requieren un tratamiento completo de MDT en dos clínicas para pacientes de lepra ambulatorios del norte de la India. Los controles fueron individuos sin lepra o condiciones neurológicas, que atendían los departamentos dermatológicos de las mismas clínicas. Se evaluó electrofisiológicamente la función neural mediante parámetros estándar para la conducción neural sensitiva y motora (NC), detección de umbrales térmicos (W/CDT), umbrales de percepción vibratoria, dinamometría, MF y VMT. Estos últimos definen los resultados de detección sensitivo y motor. Resultados: 115 pacientes presentaron deterior neural o una reacción reciente en el momento del diagnóstico. Los amplificados sensitivos y motores y WDT eran las pruebas más frecuentemente anormales. De entre todos los nervios evaluados, el safeno externo y nervio tibial posterior. En el nervio cubital, se detectaron anormalidades en el 25% de los individuos y las amplitudes en el 40%. Las velocidades de conducción del cubital sobre el codo resultaron anormales en el 39% y las amplitudes en el 32%. Las WDT se detectaron más frecuentemente que las CDT en todos los nervios evaluados. Los umbrales para todos los parámetros difieren significativamente entre controles y pacientes, mientras que las diferencias eran mínimas entre pacientes con o sin reacción. Se detectó una buena correlación entre los resultados MF y las latencias y velocidades sensitivas (concordancia del 80% para el nervio cubital). Sin embargo, una proporción de los nervios con resultados MF anormales resultaron normales en una o más de las pruebas o viceversa. La concordancia para el nervio cubital entre la VMT y las velocidades de conducción motora resultó buena, pero para los nervios medianos y peroneales, la proporción de los que presentan detección de la VMT entre los afectados por conducción motora resultó baja. Conclusiones: La concordancia entre los monofilamentos y otras pruebas de función sensitiva fue aceptable, apoyando la validez de los monofilamentos como test de cribaje para la función sensitiva. La concordancia entre VMT y conducción motora resultó buena para el cubita, pero muy pocos nervios medianos y peroneales con conducción anormal presentaron VMT anormal. Se requiere un test manual para la función motora más sensible. De entre los test de evaluación neural. De entre las pruebas neurológicas ensayadas, las más afectadas eran las amplitudes NC y la sensación de calor. Por tanto, los estudios sobre conducción neural y medidas WDT parecen ser las más prometedoras para la detección precoz de la neuropatía de la lepra. El patrón de la concordancia entre la afectación de la lepra sensibilidad térmica y táctil no apoya la hipótesis de que la neuropatía de pequeñas fibras sugiere preceder la afectación de las fibras mayores. La sensación de calor está más frecuentemente afectada que la de frío. Esto podría decir que las fibras C desmielinizadas están más frecuentemente afectadas que las fibras pequeñas Ad mielinizadas

Aim: To compare different method(s) to detect peripheral neuropathy in leprosy and to study the validity of the monofilament test (MF) and the voluntary muscle test (VMT ) as standard test of nerve function. Design: A multi-centre cohort study of 303 multibacillary (MB) leprosy patients. Methods: Newly registered MB patients requiring a full course of MDT were recruited in two leprosy outpatient clinics in North India. Controls were people without leprosy or neurological conditions, attending the dermatological outpatient departments of the same clinics. Never function was evaluated electrophysiologically using standard parameters or sensory and motor nerve conduction (NC) testing, warm and cold detection thresholds (W/CDT), vibration perception thresholds, dynamometry, MF and VMT. The latter two defined the outcomes of sensory and motor impairment. Results 115 patients had never damage or a reaction recent onset at diagnosis. Sensory and motor amplitudes and WDTs were the most frequently abnormal. Among the nerves tested, the sural and posterior tibial were the most frequently impaired. In the ulnar nerve, sensory latencies were abnormal in 25% of subjects; amplitudes in 40%. Ulnar above-elbow motor conduction velocities were abnormal in 39% and amplitudes 32%. WDTs were much more frequently affected ficanty between controls and patients, while only some differed between MF results wever, a proportion of nerves with abnormal MF results tested normal on one or more of the other test or vice versa. Concordance between VMT and motor conduction velocities was good for the ulnar nerve, but for the median and peroneal nerves, the proportion impaired by VMT out of those with abnormal motor conduction was very low. Conclusions: Concordance between monofilaments and other sensory function test results was good, supporting the validity of the monofilaments as standard screening test of sensory function. Concordance between VMT results and motor nerve conduction was good for the ulnar nerve, but vey few median and peroneal nerves with abnormal conduction had an abnormal VMT. A more sensitive manual motor test may be needed for these nerves. Of the nerve assessment tests conducted, NC amplitudes and warm sensation were the most frequently affected. There-fore, nerve conduction studies and WDT measurements appear to be most promising tests for early detection of leprous neuropathy. The pattern of concordance between tactile and thermal sensory impairment failed to support the hypothesis that small fibre neuropathy always precedes large fibre damage. Warm sensation was more frequently affected that cold sensation. This could indicate that unmyelinated C fibres are more frequently affected than small myelinated Ad fibres

The INFIR Cohort Study: investigating prediction, detection and pathogenesis of neuropathy and reactions in leprosy. Methods and baseline results of a cohort of multibacillary leprosy patients in north India.

The aim of this study was to find predictors of neuropathy and reactions, determine the most sensitive methods for detecting peripheral neuropathy, study the pathogenesis of neuropathy and reactions and create a bank of specimen, backed up by detailed clinical documentation. A multi-centre cohort study of 303 multibacillary leprosy patients in Northern India was followed for 2 years. All newly registered MB patients requiring a full course of MDT, who were smear positive and/or had six or more skin lesions and/or had two or more nerve trunks involved, were eligible. A detailed history was taken and physical and neurological examinations were performed. Nerve function was assessed at each visit with nerve conduction testing, warm and cold detection thresholds, vibrometry, dynamometry, monofilaments and voluntary muscle testing. Because the latter two are widely used in leprosy clinics, they were used as 'gold standard' for sensory and motor impairment. Other outcome events were type 1 and 2 reactions and neuritis. All subjects had a skin biopsy at registration, repeated at the time of an outcome event, along with a nerve biopsy. These were examined using a variety of immunohistological techniques. Blood sampling for serological testing was done at every 4-weekly clinic visit. At diagnosis, 115 patients had an outcome event of recent onset. Many people had skin lesions overlying a major nerve trunk, which were shown to be significantly associated with an increased of sensory or motor impairment. The most important adjusted odds ratios for motor impairment were, facial 4.5 (1.3-16) and ulnar 3.5 (1.0-8.5); for sensory impairment they were, ulnar 2.9 (1.3-6.5), median 3.6 (1.1-12) and posterior tibial 4.0 (1.8-8.7). Nerve enlargement was found in 94% of patients, while only 24% and 3% had paraesthesia and nerve tenderness on palpation, respectively. These increased the risk of reactions only marginally. Seven subjects had abnormal tendon reflexes and seven abnormal joint position sense. In all but one case, these impairments were accompanied by abnormalities in two or more other nerve function tests and thus seemed to indicate more severe neuropathy. At diagnosis, 38% of a cohort of newly diagnosed MB leprosy patients had recent or new reactions or nerve damage at the time of intake into the study. The main risk factor for neuropathy found in this baseline analysis was the presence of skin lesions overlying nerve trunks. They increased the risk of sensory or motor impairment in the concerned nerve by 3-4 times. For some nerves, reactional signs in the lesions further increased this risk to 6-8 times the risk of those without such lesions. Patients with skin lesions overlying peripheral nerve trunks should be carefully monitored for development of sensory or motor impairment.

The INFIR Cohort Study: assessment of sensory and motor neuropathy in leprosy at baseline.

AIM: To compare different method(s) to detect peripheral neuropathy in leprosy and to study the validity of the monofilament test (MF) and the voluntary muscle test (VMT) as standard tests of nerve function. DESIGN: A multi-centre cohort study of 303 multibacillary (MB) leprosy patients. METHODS: Newly registered MB patients requiring a full course of MDT were recruited in two leprosy outpatient clinics in North India. Controls were people without leprosy or neurological conditions, attending the dermatological outpatient departments of the same clinics. Nerve function was evaluated electrophysiologically using standard parameters for sensory and motor nerve conduction (NC) testing, warm and cold detection thresholds (W/CDT), vibration perception thresholds, dynamometry, MF and VMT. The latter two defined the outcomes of sensory and motor impairment. RESULTS: 115 patients had nerve damage or a reaction of recent onset at diagnosis. Sensory and motor amplitudes and WDTs were the most frequently abnormal. Among the nerves tested, the sural and posterior tibial were the most frequently impaired. In the ulnar nerve, sensory latencies were abnormal in 25% of subjects; amplitudes in 40%. Ulnar above-elbow motor conduction velocities were abnormal in 39% and amplitudes 32%. WDTs were much more frequently affected than CDTs in all nerves tested. The thresholds of all test parameters differed significantly between controls and patients, while only some differed between patients with and without reaction. Good concordance was observed between MF results and sensory latencies and velocities (direct concordance 80% for the ulnar). However, a proportion of nerves with abnormal MF results tested normal on one or more of the other tests or vice versa. Concordance between VMT and motor conduction velocities was good for the ulnar nerve, but for the median and peroneal nerves, the proportion impaired by VMT out of those with abnormal motor conduction was very low. CONCLUSIONS: Concordance between monofilaments and other sensory function test results was good, supporting the validity of the monofilaments as standard screening test of sensory function. Concordance between VMT results and motor nerve conduction was good for the ulnar nerve, but very few median and peroneal nerves with abnormal conduction had an abnormal VMT. A more sensitive manual motor test may be needed for these nerves. Of the nerve assessment tests conducted, NC amplitudes and warm sensation were the most frequently affected. Therefore, nerve conduction studies and WDT measurements appear to be most promising tests for early detection of leprous neuropathy. The pattern of concordance between tactile and thermal sensory impairment failed to support the hypothesis that small fibre neuropathy always precedes large fibre damage. Warm sensation was more frequently affected than cold sensation. This could indicate that unmyelinated C fibres are more frequently affected than small myelinated Asigma fibres.