Introduction: Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment seen within the outpatient orthopaedic clinic; therefore assessment and management of this common condition is of significant importance. Traditionally diagnosis has been made through detailed questioning; clinical examination and nerve conduction studies (NCS). There is however no true consensus as to the gold standard assessment of CTS and the use of NCS can confer additional costs and delay treatment. Previous studies have explored methods of predicting the presence of CTS including the clinician-administered Carpal Tunnel Questionnaire (CTQ) (Kamath and Stothard, 2003). The aim of the present studies is therefore to explore the versatility of the CTQ to see how a novel Patient-completed Version of the CTQ compares to the original Clinican-completed version. Psychometric properties of the questionnaire will be explored together the economic impact of integrating both versions within an orthopaedic care pathway. A further aim is to answer whether the CTQ more effective and cost-effective than NCS for patients referred to an orthopaedic clinic with suspected CTS. Method: 100 patients referred for further investigation of suspected CTS were assessed using parallel patient and clinician-completed versions of the CTQ and results were subsequently compared with those obtained from NCS. Item analysis explored each of the nine constructs of the questionnaire and the original scoring algorithm was validated using binary logistic regression and compared with alternative algorithms. Sensitivity and specificity of the questionnaire when compared to results of NCS was explored using Receiver Operating Characteristic (ROC) analyses. Inter-rater reliability was explored through Pearson’s correlation coefficient. Economic analysis and modelling was carried out to explore potential cost savings of use of the questionnaire rather than NCS for those with suspected CTS. Results demonstrated sensitivity of 92% and specificity of 54.67% (positive predictive value 95.35%) for the patient-completed questionnaire and 96% sensitivity with 70.67% specificity (98.15 positive predictive value) for the clinician-completed questionnaire when used to predict the outcome of NCS. Binary logistic regression confirmed the original scoring algorithm and a revised algorithm did not significantly improve sensitivity. Adoption of the clinician-completed CTQ would have screen out 54% of referrals for NCS, which in the case of the study site would have conferred cost savings of £73,305 per annum (base upon a referral rate of 750 per annum). The patient-completed CTQ in the current sample resulted in 43% of referrals with suspected CTS not requiring NCS to assist in diagnosis with a potential saving of £58,372.5 per annum. There are further considerations of the reduction in waiting times, which are explored further within the analysis. Conclusion: Economic evaluation is complex due to the variety of pathways adopted by different orthopaedic departments. While the results of the Patient-complete version of the CTQ may not be as convincing as the clinician completed the study does provide validation for its use and expands the versatility of this useful adjunct to the assessment of CTS. Both versions could potentially confer significant cost savings and reduce demands on investigative services, reducing waiting times and improving the patient journey in suspected CTS.

O envolvimento do sistema nervoso periférico em diversas doenças auto-imunes é bem estabelecido. No entanto, não existem estudos, com desenho metodológico apropriado, que tenham investigado a relação entre síndrome antifosfolípide primária (SAFP) e neuropatia periférica. Nosso objetivo nesse trabalho foi investigar a ocorrência de neuropatia periférica em pacientes com SAFP. Vinte e seis pacientes com SAFP (critérios de Sapporo) e vinte controles, saudáveis, pareados por sexo e idade, foram recrutados em dois centros de referência. Foram excluídas as causas secundárias de neuropatia periférica e um exame neurológico completo, seguido de estudo de neurocondução, foi realizado em todos os indivíduos. Parestesias foram observadas em oito pacientes (31%). Leve fraqueza distal e anormalidades nos reflexos tendíneos profundos, foram observados em três (11,5%) pacientes. Evidência eletrofisiológica de neuropatia periférica foi observada em nove (35%) pacientes: quatro (15,5%) pacientes apresentaram neuropatia sensitiva ou sensitivo-motora axonal distais (em dois deles, com a superposição de síndrome do túnel do carpo), um (4%) paciente apresentou neuropatia sensitivo-motora, axonal e desmielinizante, acometendo os membros superiores e inferiores, enquanto que em quatro (15,5%) pacientes, observou-se a presença isolada de síndrome do túnel do carpo. As alterações clínicas e sorológicas dos pacientes com SAFP não guardaram qualquer correlação, com as alterações eletrofisiológicas. Em conclusão, neuropatia periférica, em geral assintomática, é comum na SAFP. Estudo de condução nervosa deve ser considerado na avaliação desses pacientes. / The involvement of the peripheral nervous system in diverse autoimmune diseases is well established. However, no appropriately designed studies have been performed in primary antiphospholipid syndrome (PAPS)-related peripheral neuropathy. We aimed to investigate the occurrence of peripheral neuropathy in patients diagnosed with PAPS. Twenty-six consecutive PAPS (Sapporo\'s criteria) patients and twenty age- and gender-matched healthy controls were enrolled at two referral centers. Exclusion criteria were secondary causes of peripheral neuropathy. A complete clinical neurological exam followed by nerve conduction studies (NCSs) were performed. Paresthesias were reported in 8 patients (31%). Objective mild distal weakness and abnormal symmetric deep tendon reflexes were observed in three (11.5%) patients. With regard to the electrophysiological evidence of peripheral neuropathy, nine (35.0%) patients had alterations: four (15.5%) had pure sensory or sensorimotor distal axonal neuropathy (in two of them a carpal tunnel syndrome was also present) and one (4%) had sensorimotor demyelinating and axonal neuropathy involving upper and lower extremities, while four patients (15.5%) showed isolated carpal tunnel syndrome. Clinical and serological results were similar in all PAPS patients, regardless of the presence of electrophysiological alterations. In conclusion, peripheral neuropathy is a common asymptomatic abnormality in PAPS patients. The routine performance of NCS may be considered when evaluating such patients.

O envolvimento do sistema nervoso periférico em diversas doenças auto-imunes é bem estabelecido. No entanto, não existem estudos, com desenho metodológico apropriado, que tenham investigado a relação entre síndrome antifosfolípide primária (SAFP) e neuropatia periférica. Nosso objetivo nesse trabalho foi investigar a ocorrência de neuropatia periférica em pacientes com SAFP. Vinte e seis pacientes com SAFP (critérios de Sapporo) e vinte controles, saudáveis, pareados por sexo e idade, foram recrutados em dois centros de referência. Foram excluídas as causas secundárias de neuropatia periférica e um exame neurológico completo, seguido de estudo de neurocondução, foi realizado em todos os indivíduos. Parestesias foram observadas em oito pacientes (31%). Leve fraqueza distal e anormalidades nos reflexos tendíneos profundos, foram observados em três (11,5%) pacientes. Evidência eletrofisiológica de neuropatia periférica foi observada em nove (35%) pacientes: quatro (15,5%) pacientes apresentaram neuropatia sensitiva ou sensitivo-motora axonal distais (em dois deles, com a superposição de síndrome do túnel do carpo), um (4%) paciente apresentou neuropatia sensitivo-motora, axonal e desmielinizante, acometendo os membros superiores e inferiores, enquanto que em quatro (15,5%) pacientes, observou-se a presença isolada de síndrome do túnel do carpo. As alterações clínicas e sorológicas dos pacientes com SAFP não guardaram qualquer correlação, com as alterações eletrofisiológicas. Em conclusão, neuropatia periférica, em geral assintomática, é comum na SAFP. Estudo de condução nervosa deve ser considerado na avaliação desses pacientes. / The involvement of the peripheral nervous system in diverse autoimmune diseases is well established. However, no appropriately designed studies have been performed in primary antiphospholipid syndrome (PAPS)-related peripheral neuropathy. We aimed to investigate the occurrence of peripheral neuropathy in patients diagnosed with PAPS. Twenty-six consecutive PAPS (Sapporo\'s criteria) patients and twenty age- and gender-matched healthy controls were enrolled at two referral centers. Exclusion criteria were secondary causes of peripheral neuropathy. A complete clinical neurological exam followed by nerve conduction studies (NCSs) were performed. Paresthesias were reported in 8 patients (31%). Objective mild distal weakness and abnormal symmetric deep tendon reflexes were observed in three (11.5%) patients. With regard to the electrophysiological evidence of peripheral neuropathy, nine (35.0%) patients had alterations: four (15.5%) had pure sensory or sensorimotor distal axonal neuropathy (in two of them a carpal tunnel syndrome was also present) and one (4%) had sensorimotor demyelinating and axonal neuropathy involving upper and lower extremities, while four patients (15.5%) showed isolated carpal tunnel syndrome. Clinical and serological results were similar in all PAPS patients, regardless of the presence of electrophysiological alterations. In conclusion, peripheral neuropathy is a common asymptomatic abnormality in PAPS patients. The routine performance of NCS may be considered when evaluating such patients.

<p>Neurography is the most objective and reliable measure of the peripheral nerve function, and it is used to diagnose both local and generalized neuropathies. Neurography can measure both motor and sensory nerve functions. The principle for sensory neurgraphy is to stimulate over the nerve and record proximal or distal from the stimulated electrode.</p><p>At the Department of Clinical Neurophysiology, University Hospital Uppsala, a problem has been identified, in that young adult patients tend to show unexpected abnormal neurography values in relation to the expected, indicated by the reference limits, without clinical correlates. This concerns foremost the sensory amplitudes in median and ulnar nerves. The hypothesis is that the requirement of young adults’ amplitudes is too high. A reference material better including more subjects in this age group may solve the problem.</p><p>Sensory nerve conduction studies were performed in 33 subjects, aged 15-30. The nerve functions were tested on median, ulnar and radial nerves. Surface electrodes were used for both recording and stimulation.</p><p>The result shows that the presently used reference material for some nerves indeed has too high requirement for young adults. After increasing the reference material for younger age groups, the new reference limits has been changed and this should cause fewer false positive findings.</p>

Experimental measurements are never perfect, even with sophisticated modern instruments. One of the fundamental problems in signal measurement is distinguishing the noise from the signal. Sometimes the two can be partly distinguished on the basis of frequency components: for example, the signal may contain mostly low-frequency components and the noise may be located at higher frequencies. This is the basis of filtering. This thesis discusses some changes in the experimental protocol such as determining a suitable stimulation site to elicit full compound nerve action potentials (CNAP). The effect of sampling frequency and smoothing techniques to improve the resolution of the conduction velocity distribution (CVD) estimates will also be discussed. A change in stimulation site to elicit the full CNAPs is proposed after realizing that it is relatively difficult to stimulate at the same location to recruit the nerve fibers repeatedly at the elbow. Thus, the stimulation site was changed from elbow to wrist to elicit the full CNAPs. From the simulations it is evident that there was some signal information beyond 2.5 kHz frequency resulting in an increase in the sampling rate from 5 kHz to 10 kHz. The results obtained after employing smoothing techniques improved the CVD resolution. The simulation results were corroborated with the experimental results obtained. Another aspect of this thesis is to check the error tolerance of the EMG decomposition algorithm. Once the muscle electrical activity is recorded, MU trains undergo an automatic decomposition process. Decomposition errors are present in most contractions, thus a human operator has to make changes/correct the values of the motor unit firing times. From the data acquired, false negatives, false positives and false negative-positive errors have been introduced. Different levels of errors to measure the coherence between two motor-unit firing trains from a muscle contraction were also introduced. The firing rate curves are computed for each MU to analyze the interactions between two motor units (MU). The false negatives type of errors was found to be least detrimental. Whereas the false positives and false negative-positive errors affected coherence the most, their error tolerance was only a single error per 5 seconds.

Submitted by BRENO JOSE HULLE PEREIRA null (brenojhp@hotmail.com) on 2016-04-09T14:37:30Z No. of bitstreams: 1 Qualidade do sono em pacientes com síndrome do túnel do carpo - Pós defesa.pdf: 1149395 bytes, checksum: 10d3bbaef52562ba5ec7284510070c8c (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-04-11T13:04:38Z (GMT) No. of bitstreams: 1 pereira_bjh_me_bot.pdf: 1149395 bytes, checksum: 10d3bbaef52562ba5ec7284510070c8c (MD5) / Made available in DSpace on 2016-04-11T13:04:38Z (GMT). No. of bitstreams: 1 pereira_bjh_me_bot.pdf: 1149395 bytes, checksum: 10d3bbaef52562ba5ec7284510070c8c (MD5) Previous issue date: 2016-03-02 / Frequentemente os sintomas da síndrome do túnel do carpo (STC) ocorrem à noite, mas a relação entre STC e características do sono destes pacientes ainda não foram sistematicamente investigadas através de métodos objetivos, tais como a eletroneuromiografia (ENMG) e a polissonografia (PSNG), o que constitui o objetivo deste estudo. Métodos: Pacientes do sexo feminino com STC, diagnosticadas por estudo de condução nervosa (ENMG), foram estudadas por exames de polissonografia e listadas de acordo com a gravidade da STC, mensurada pela latência motora distal (LMD) do nervo mediano da mão ou mãos afetadas, e seus dados polissonográficos foram analisados. Resultados: 42 pacientes foram estudadas de Junho de 2011 a Junho de 2015. O Índice de Despertares (ID) das pacientes com STC acentuada mostrou-se alterado em uma porcentagem maior do que nas pacientes com STC leve ou moderada (100, 60 e 66%, respectivamente). Essa relação de prevalência se manteve quando o Tempo de Dessaturação (TD) foi analisado. Alterações da Eficiência do Sono (ES) foram mais comuns em pacientes com STC bilateral. Arquitetura do sono está igualmente alterada em todos os pacientes, com sono de ondas lentas (N3) e sono REM diminuídos em todos os grupos. A presença de Síndrome da Apneia Obstrutiva do Sono (SAOS) não dependeu da gravidade da STC. Conclusões: Quanto mais grave a STC documentada por ENMG, mais prevalente é o sono fragmentado e a dessaturação do sono. No entanto, analise aprofundada é necessária para se estabelecer relações entre a qualidade do sono e a gravidade da STC. / Frequently the symptoms of the carpal tunnel syndrome (CTS) occur at night time, but the relation between CTS and the sleep characteristics of those patients have yet to be systematically described by objective methods, such as conduction studies (ENMG) and polysomnography (PSG), which is the aim of this study. Methods: Consecutive female patients with CTS diagnosed by ENMG were studied by polysomnographic exams and listed in accordance with CTS severity, evaluated by distal motor latency of the median nerve of the affected hand or hands, and their polysomnographic data were analysed. Results: 42 patients were studied from June 2011 to June 2015. The Arousal Index (AI) of the patients with severe CTS were altered in larger proportion of those individuals than in those patients with slight or moderate CTS (100, 60% and 66%, respectively). This relation was also prevalent when the Desaturation Time (DT) was analyzed. Alterations of the Sleep Efficiency (SE) were more common among patients with bilateral CTS. Sleep architecture was equally altered among all patients, with slow wave sleep (SWS) and REM sleep diminished in all groups. The presence of Obstructive Sleep Apnea (OSA) was not dependent on CTS severity. Conclusions: The larger the CTS severity evaluated by ENMG, the more prevalent were fragmented sleep and sleep desaturation. Further analysis is required to ascertain causal relations between sleep quality and CTS severity.

Orientador: Luiz Antonio de Lima Resende / Resumo: Frequentemente os sintomas da síndrome do túnel do carpo (STC) ocorrem à noite, mas a relação entre STC e características do sono destes pacientes ainda não foram sistematicamente investigadas através de métodos objetivos, tais como a eletroneuromiografia (ENMG) e a polissonografia (PSNG), o que constitui o objetivo deste estudo.Métodos: Pacientes do sexo feminino com STC, diagnosticadas por estudo de condução nervosa (ENMG), foram estudadas por exames de polissonografia e listadas de acordo com a gravidade da STC, mensurada pela latência motora distal (LMD) do nervo mediano da mão ou mãos afetadas, e seus dados polissonográficos foram analisados.Resultados: 42 pacientes foram estudadas de Junho de 2011 a Junho de 2015. O Índice de Despertares (ID) das pacientes com STC acentuada mostrou-se alterado em uma porcentagem maior do que nas pacientes com STC leve ou moderada (100, 60 e 66%, respectivamente). Essa relação de prevalência se manteve quando o Tempo de Dessaturação (TD) foi analisado. Alterações da Eficiência do Sono (ES) foram mais comuns em pacientes com STC bilateral. Arquitetura do sono está igualmente alterada em todos os pacientes, com sono de ondas lentas (N3) e sono REM diminuídos em todos os grupos. A presença de Síndrome da Apneia Obstrutiva do Sono (SAOS) não dependeu da gravidade da STC.Conclusões: Quanto mais grave a STC documentada por ENMG, mais prevalente é o sono fragmentado e a dessaturação do sono. No entanto, analise aprofundada é neces... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Frequently the symptoms of the carpal tunnel syndrome (CTS) occur at night time, but the relation between CTS and the sleep characteristics of those patients have yet to be systematically described by objective methods, such as conduction studies (ENMG) and polysomnography (PSG), which is the aim of this study.Methods: Consecutive female patients with CTS diagnosed by ENMG were studied by polysomnographic exams and listed in accordance with CTS severity, evaluated by distal motor latency of the median nerve of the affected hand or hands, and their polysomnographic data were analysed.Results: 42 patients were studied from June 2011 to June 2015. The Arousal Index (AI) of the patients with severe CTS were altered in larger proportion of those individuals than in those patients with slight or moderate CTS (100, 60% and 66%, respectively). This relation was also prevalent when the Desaturation Time (DT) was analyzed. Alterations of the Sleep Efficiency (SE) were more common among patients with bilateral CTS. Sleep architecture was equally altered among all patients, with slow wave sleep (SWS) and REM sleep diminished in all groups. The presence of Obstructive Sleep Apnea (OSA) was not dependent on CTS severity.Conclusions: The larger the CTS severity evaluated by ENMG, the more prevalent were fragmented sleep and sleep desaturation. Further analysis is required to ascertain causal relations between sleep quality and CTS severity. / Mestre

Neurography is the most objective and reliable measure of the peripheral nerve function, and it is used to diagnose both local and generalized neuropathies. Neurography can measure both motor and sensory nerve functions. The principle for sensory neurgraphy is to stimulate over the nerve and record proximal or distal from the stimulated electrode. At the Department of Clinical Neurophysiology, University Hospital Uppsala, a problem has been identified, in that young adult patients tend to show unexpected abnormal neurography values in relation to the expected, indicated by the reference limits, without clinical correlates. This concerns foremost the sensory amplitudes in median and ulnar nerves. The hypothesis is that the requirement of young adults’ amplitudes is too high. A reference material better including more subjects in this age group may solve the problem. Sensory nerve conduction studies were performed in 33 subjects, aged 15-30. The nerve functions were tested on median, ulnar and radial nerves. Surface electrodes were used for both recording and stimulation. The result shows that the presently used reference material for some nerves indeed has too high requirement for young adults. After increasing the reference material for younger age groups, the new reference limits has been changed and this should cause fewer false positive findings.

A neuropatia hansênica e a neuropatia hereditária com suscetibilidade à pressão (Hereditary Neuropathy with liability to Pressure Palsies - HNPP) são mononeuropatias múltiplas em que os estudos da condução nervosa (ECN) mostram geralmente alentecimento focal em topografias muito semelhantes. Na ausência de uma história familiar de HNPP e das manifestações na pele típicas da hanseníase, o diagnóstico diferencial entre elas pode ser muito difícil. Procurando identificar características que ajudassem a distinguir essas doenças, revisamos e catalogamos os dados da história clínica e dos ECN de 39 pacientes com HNPP e 78 pacientes com neuropatia hansênica. A manifestação inicial mais frequente na hanseníase foi o déficit sensitivo (43 pacientes-55.1%) e na HNPP foi a fraqueza muscular localizada indolor (24 pacientes-61%). Fraqueza muscular foi significativamente superior na HNPP e déficit sensitivo foi significativamente superior na hanseníase (p<0.001). A evolução clínica foi estável ou progressiva até o tratamento em todos os pacientes com hanseníase e na HNPP dez pacientes (25.6%) tiveram um curso progressivo e 29 (74.4%) uma evolução com flutuações. O padrão predominante ao exame neurológico foi a mononeuropatia múltipla: 66 pacientes (84.6%) na hanseníase e 26 pacientes (66.7%) na HNPP. Espessamento neural foi mais frequente na hanseníase (p=0,001) e déficit sensitivo intradérmico foi observado somente na hanseníase (p<0,001). Episódio prévio ou atual de paralisia aguda de nervo foi referido somente na HNPP (p<0,001). O padrão dos ECN prevalente foi a neuropatia sensitivo-motora assimétrica com alentecimento focal da condução (NSMAAF): 44 pacientes (56.4%) na hanseníase e 31 pacientes (94.0%) na HNPP. Os parâmetros clínicos mais úteis em distinguir as duas doenças foram: a perda sensitiva intradérmica com comprometimento precoce das fibras finas e ocorrência de reação hansênica na hanseníase; o envolvimento motor inicial predominante, episódios de paralisia aguda de nervo e a evolução com flutuações na HNPP. Se o paciente a ser avaliado apresentar mononeuropatia múltipla com alentecimentos focais da velocidade de condução, os seguintes achados neurofisiológicos sugerem hanseníase: a não detecção de potenciais sensitivos ou motores, a redução da amplitude dos potenciais de ação sensitivos dos nervos sural, fibular superficial e radial superficial (< 8,8 ?V), a redução da amplitude do potencial de ação muscular composto dos nervos ulnar e tibial posterior, a redução da velocidade de condução do potencial de ação muscular composto do nervo ulnar motor no segmento do antebraço (< 43 m/s) e a presença de dispersão temporal frequente; enquanto os seguintes achados sugerem HNPP: aumento desproporcional da latência distal do nervo mediano motor e a presença de bloqueio de condução. / The Hansen\'s disease neuropathy (HDN) and the Hereditary Neuropathy with liability to Pressure Palsies (HNPP) are multiple mononeuropathies whose nerve conduction studies (NCS) usually show focal slowing at very similar topographies. In the absence of a family history of HNPP and the typical skin manifestations of HD, the differential diagnosis between them may be very difficult. In order to identify characteristics that may distinguish these diseases, we reviewed the data of 39 patients with HNPP and of 78 patients with HDN. The most frequent presenting sign was a sensory deficit in 43 patients (55.1%) in the HDN and a localized painless muscular weakness in 24 patients (61%) in the HNPP. Muscle weakness was significantly higher in HNPP and sensory deficit was significantly higher in leprosy (p<0.001). The disease was stable or progressive until treatment in all patients with HDN and among HNPP ten patients (25.6%) had a progressive course and 29 (74.4%) an intermittent evolution. Neural thickening was more frequent in leprosy (p=0.001) and intradermal sensory deficit was observed only in leprosy (p<0.001). Previous or current episode of acute nerve palsy was reported only in HNPP (p<0.001). The predominant pattern on neurological examination was the multiple mononeuropathy: 66 patients (84.6%) in the HDN and 26 patients (66.7%) in the HNPP. The most prevalent pattern of NCS was an asymmetric sensorimotor neuropathy with focal slowing (ASMNFS): 44 patients (56.4%) in HDN and 31 patients (94.0%) in HNPP. The most helpful clinical parameters in distinguishing these diseases were the presence of leprosy reaction and the intradermal sensory loss with predominant early involvement of small nerve fibers in HDN; the initial predominant motor involvement, episodes of acute nerve palsies and the intermittent evolution in HNPP. If the patient evaluation show a pattern of multiple mononeuropathy with focal slowing, the following neurophysiological findings suggest HDN: no detection of sensory or motor potentials, amplitude reduction of the sural, superficial fibular and superficial radial (<8.8 ?V) nerves, amplitude reduction of the motor ulnar and posterior tibial nerves, reduction of the conduction velocity of the motor ulnar nerve at the forearm segment (<43 m/s) and the presence of frequent temporal dispersion; while the following findings suggest HNPP: a disproportionate increase in the motor distal latency of the median nerve and the presence of conduction block.

Bakgrund: Nervus medianus är armens mittersta nerv med både efferenta och afferenta nervfibrer. För att undersöka perifera nerver används neurografi. N. medianus sensorik går att undersöka både ortodromt och antidromt där den antidroma metoden framförallt används vid karpaltunnelsyndromfrågeställning. Vanligtvis stimuleras nerven då 7 respektive 14 cm från registreringspunkten på digitorum III, men det finns fördelar med att istället för 7 cm-punkten använda sig av proximal stimulering ovanför armvecket. För denna metod finns dock ont om referensvärden. Syftet med denna studie var därför att samla in referensvärden för latenstider och amplituder.  Metod: Försökspersonerna bestod av 34 personer mellan 22 och 65 år. N. medianus undersöktes sensoriskt med proximal stimulering och registrering på dig III med både 0,1 och 0,2 ms impulsduration.  Resultat: Peaklatenstider varierade mellan 5,94 och 8,7 ms (x̄=7,00 ms) och amplituder varierade mellan 7,2 𝜇V och 72,6 𝜇V (x̄=35,6) vid 0,1 ms impulsduration. Det fanns ett signifikant bidrag av både längd och ålder på både latenstider och amplituder och en signifikant könsskillnad mellan män och kvinnor kunde uppmätas. Det fanns en signifikant, men mycket liten, skillnad i latenstid för impulsduration, men inga skillnader i amplituder. Variationskoefficienten för tre upprepade mätningar varierade mellan 0,9 och 5,3 % för peaklatens och 1,0 och 15,6 % för amplitud.  Slutsats: Hos friska försökspersoner ses en viss variation för amplituder medan latenstider ligger mer samlat. Ålder och längd bör tas med i beräkning av individuella normalvärden och en könsaspekt kan inte heller uteslutas. Impulsduration bör inte ha någon klinisk relevans. Reliabiliteten är bättre för latenstider än amplituder. / Background:. Sensory nerves can be examined both orthodromic and antidromic with nerve conduction studies. In the mixed median nerve is the antidromic method mainly used for evaluation of carpal tunnel syndrome. Usually the nerve is stimulated 7 and 14 cm from the recording at digitorum III, but there are some advantages in changing the 7 cm stimulation point to a more proximal one. The purpose of this study was to collect reference values for peak latency times and amplitudes with a proximal stimulation.  Methods: 34 test subjects in the age of 22-65 years were recruited for the study. Sensory nerve conduction studies of the median nerve with proximal stimulation and recording at digitorum III were performed with both 0,1 and 0,2 ms stimulus duration.  Results: Latency times varied between 5,94 and 8,7 ms (x̄=7,00 ms) and amplitudes varied between 7,2 𝜇V and 72,6 𝜇V (x̄=35,6) when 0,1 ms stimulus duration was used. There was a significant contribution by both length and age on latency times and amplitudes and a significant sex difference. There was a small difference in latency times by stimulus duration, but not in amplitudes. The coefficient of variation varied between 0,9 and 5,3 % for peak latency time and 1,0 and 15,6 % for amplitude.  Conclusion: There was some variation in amplitudes, but the latency times were more gathered together. Age and length have to be taken in consideration while individually reference values are calculated and a sex difference cannot be ruled out. Stimulus duration probably does not have a clinically relevant impact. The reliability is better for latency times than for amplitudes.