Two-point discrimination and judgment of laterality in individuals with chronic unilateral non-traumatic shoulder pain.

BACKGROUND: Cortical representation of the painful body region may be disrupted in several chronic pain conditions. The two-point discrimination test (TPDT) and the Left/Right Judgement Task (LRJT) have been used to identify changes in the cortical body schema in several chronic pain conditions. However, it is unclear if these changes are present for all chronic pain mechanisms. OBJECTIVES: To investigate the integrity of the body schema of the painful shoulder in patients with chronic unilateral nociceptive shoulder pain. METHODS: The sample consisted of 52 individuals with chronic unilateral nociceptive shoulder pain. The TPDT was measured over the anterosuperior and lateral regions of both shoulders using a staircase method. Participants also performed judgment tests of shoulder and foot laterality. The comparison of the TPDT and LRJT was performed using the linear regression model with mixed effects. RESULTS: There was no difference in TPDT in the anterosuperior and lateral regions when comparing the symptomatic and asymptomatic shoulders. There was no difference in the LRJT accuracy and response time between the symptomatic and asymptomatic shoulders. No differences were observed when comparing LRJT variables from symptomatic shoulder and foot. CONCLUSION: Therefore, results do not provide clear evidence of altered body schema in chronic nociceptive unilateral shoulder pain. This suggest that alterations in body representations may depend on the primary pain mechanism.

Clinical evaluation of somatosensory integrity in people with chronic shoulder pain.

PURPOSE: Indirect evaluation tests of somatosensory integrity, such as the left/right judgment task and two-point discrimination thresholds, are used to complement a clinical evaluation facilitating tailored rehabilitation programs for patients with chronic pain. This study aimed to compare performance on the left/right judgment task and two-point shoulder discrimination thresholds between people with chronic shoulder pain and asymptomatic controls. The study's secondary objective was to investigate whether there is a relationship between pain intensity and the painful area with TPDT and LRJT. MATERIALS AND METHODS: It is a cross-sectional study with a control group. Volunteers participated in the left/right judgment task using the Recognise ShoulderTM app, and two-point discrimination thresholds were performed using a Mitutoyo® digital caliper. The extent of the painful area, affectivity, and functionality were also determined to characterize the sample. RESULTS: We assessed 52 symptomatic and 50 asymptomatic individuals. A between-group difference was observed in time response for the left/right judgment task (p = 0.025) and the two-point discrimination thresholds when tested over the shoulder's lateral region (p = 0.012). There was a significant positive weak correlation between pain intensity and TPDT test performance over the anterior shoulder (rs = 0.35; p = 0.01) and a positive weak correlation between pain area and LRJT response time (rs = 0.26; p = 0.04). CONCLUSIONS: This study demonstrates a difference of small magnitude in the response time of the LRJT for the shoulder segment and TPDT in the lateral shoulder region between individuals with chronic shoulder pain and asymptomatic controls.

Confiabilidade e validade de um dispositivo de célula de carga para avaliação da força de preensão palmar / Fiabilidad y validez de un dispositivo de célula de carga para evaluar la fuerza de prensión palmar / Reliability and validity of a load cell device for hand grip strength assessment

RESUMO A força de preensão palmar é uma medida influenciada por diversos fatores como sexo, idade, motivação, treinamento muscular, dominância, altura, peso, variáveis socioeconômicas, participação em esportes específicos ou profissões. Pode ser mensurado por meio da dinamometria ou por medidores de tensão como as células de carga (strain gauges ). Confiabilidade e validade são importantes propriedades psicométricas que avaliam a reprodutibilidade da medida de um instrumento e sua aplicabilidade. Desse modo, o objetivo deste estudo foi avaliar a confiabilidade teste-reteste e a validade de constructo de uma célula de carga para medida da força de preensão palmar isométrica, em voluntários assintomáticos e portadores de disfunções no punho e mão. Foram utilizados métodos padronizados de posicionamento do membro superior e realizada aleatorização da ordem das coletas. A análise estatística de confiabilidade foi realizada pelo ICC e a validade de constructo pelo coeficiente de correlação de Pearson (r), com p <0,05, com IC de 95%, utilizando o SPSS versão 20(r). A amostra constou de 24 voluntários saudáveis com idade média de 22,25 anos, todos universitários, e 21 voluntários portadores de disfunções do membro superior e mão, de ambos os sexos. A confiabilidade teste-reteste para o grupo dos indivíduos assintomáticos foi ICC 0,90 (0,78-0,95), no grupo dos portadores de disfunções do punho e mão o ICC encontrado foi 0,94 (0,87-0,97), ambos considerados excelentes. Os gráficos de Bland e Altman mostraram que, embora a confiabilidade apresentasse níveis excelentes e com baixos valores de erro padrão de medida, alguns dados discrepantes foram encontrados. Os coeficientes de correlação de Pearson foram altos tanto para o grupo de indivíduos assintomáticos (r=0,85), como para o grupo de pacientes (r=0,83). Conclusão: baseado nos achados da amostra analisada é sugerido que a célula de carga seja um dispositivo confiável e válido para a medida de força de preensão palmar isométrica da mão, podendo ser utilizado em futuros estudos e na prática clínica.

RESUMEN La fuerza de prensión palmar es una medida influida por diversos factores tales como, sexo, edad, motivación, entrenamiento muscular, dominio, altura, peso, variables socioeconómicas, participación en deportes específicos o profesiones. Se la puede medir mediante la dinamometría o por medidores de tensión como las células de carga (strain gauges ). La fiabilidad y la validez son importantes propiedades psicométricas que evalúan la reproducibilidad de un instrumento de medición y su aplicabilidad. De esa manera, este estudio tuvo la pretensión de evaluar la fiabilidad test-retest y la validez del constructo de una célula de carga para medir la fuerza de prensión palmar isométrica, en participantes asintomáticos y en portadores de trastornos de la muñeca y de la mano. Se utilizaron métodos estandarizados de posicionamientos del miembro superior y se llevó a cabo la aleatorización del orden de la recolección de datos. El análisis estadístico de fiabilidad fue realizado por el ICC y la validez del constructo por el coeficiente de correlación de Pearson (r), con p<0,05, con IC de 95%, utilizando el SPSS en la versión 20(r). El muestreo contó con 24 personas saludables con un promedio de 22,25 años de edad, todos universitarios, y 21 personas portadoras de trastornos del miembro superior y de la mano, de ambos los sexos. La fiabilidad test-retest para el grupo de sujetos asintomáticos fue de ICC 0,90 (0,78-0,95), en el grupo de los portadores de trastornos de la muñeca y de la mano el ICC encontrado fue de 0,94 (0,87-0,97), ambos considerados excelentes. En los gráficos de Bland y Altman se mostró que aunque la fiabilidad presente niveles excelentes y con bajos valores de error estándar de medida, se encontraron algunos datos divergentes. Los coeficientes de correlación de Pearson fueron altos tanto para el grupo de sujetos asintomáticos (r=0,85) como para el grupo de portadores (r=0,83). Con base en los resultados de la muestra evaluada se propone que la célula de carga puede ser un dispositivo fiable y válido para medir la fuerza de presión palmar isométrica de la mano, y que puede utilizarla futuramente en investigaciones y en la práctica clínica.

ABSTRACT The grip strength is a complex measure influenced by factors such as gender, age, motivation, muscle training, handedness, height, weight, socioeconomic variables, and participation in specific sports or professions. It can be measured by dynamometers or by tension meters such as load cells (strain gauges). Reliability and validity are important psychometric properties, which analyze consistency and applicability of an instruments' measurement. Thus, the aim of this study was to evaluate the test-retest reliability and construct validity of a load cell device in isometric grip force measurements using a sample of asymptomatic subjects and patients with wrist and hand dysfunctions. Standardized methods of the upper limb positioning and randomization of the sample order were used. Statistical analysis of reliability was conducted by the ICC (Intraclass Correlation Coefficient) and the construct validity by Pearson correlation coefficient (r), with p<0.05, 95% CI, using SPSS version 20(r). The sample consisted of 24 healthy volunteers with an average age of 22.25 years old, all college students, and 21 volunteers with upper extremity and hand disorders, from both genders. The test-retest reliability for the asymptomatic group was ICC 0.90 (0.78-0.95) and for the group of patients was 0.94 (0.87-0.97), both considered excellent. The Bland and Altman graphics showed that although the reliability has displayed excellent levels and low standard error values of measurement, some discrepant data were found. Pearson correlation coefficients were high, both for the asymptomatic group (r=0.85), and for the patients group (r=0.83). Conclusion: based on these findings, it is suggested that this load cell is a reliable and valid device for isometric grip strength measurement and its use is suitable for future clinical trials and practice.