Effects of transcutaneous electrical nerve stimulation and cryotherapy on pain threshold by induced pressure / Efectos de la estimulación eléctrica nerviosa transcutánea y crioterapia en el umbral de dolor inducida por presión / Efeitos da estimulação elétrica nervosa transcutânea e da crioterapia sobre o limiar de dor induzida por pressão

Studies have shown that cryotherapy, transcutaneous electrical nerve stimulation (TENS) and the association of them promotes analgesia, but the effectiveness of this association is unclear. The objective was to evaluate the effects of single and combined application of TENS and cryotherapy on pressure-induced pain threshold in healthy subjects. The sample consisted of 40 subjects, randomly assigned into four groups: (1) cryotherapy group - CG, (2) TENS group - GT; (3) cryotherapy + TENS group - GCT; (4) placebo group - GP. The pain threshold was determined by an algometer before (T1), immediately after (T2) and in the instants 10 (T3), 20 (T4) and 30 (T5) minutes after application of the analgesic techniques. TENS (100 Hz, 40 μs) and cryotherapy (cold compress) were applied for 20 minutes in the GC, GT and GTC, while in the GP was simulated electrical stimulation for the same period of time. Repeated measures ANOVA and Bonferroni post hoc test were employed, considering a significance level of 5%. All experimental groups showed an increase in pain threshold when compared to GP: GC (p<0.001), GT (p<0.009) and GCT (p<0.008). In relation to the time of analgesia, there was an increase in pain threshold in T2 for all experimental groups (p <0.001) up T3 to GCT (p <0.001) and only in the GC analgesia lasted up to T5. We concluded that under the conditions studied, the three experimental groups had an increase in pain threshold compared to the GP, but cryotherapy had more prolonged effect.

Estudios tienen demostrado que la crioterapia, la estimulación eléctrica nerviosa transcutánea (TENS) y la asociación de ellas promueven analgesia, pero la efectividad de esa asociación no está clara. Se objetivó evaluar los efectos de la aplicación aislada y asociada de la TENS y de la crioterapia sobre el umbral doloroso inducido por presión en sujetos saludables. La muestra incluyó 40 sujetos aleatoriamente separados en cuatro grupos.: (1) grupo crioterapia - GC; (2) grupo TENS - GT; (3) grupo crioterapia + TENS - GCT; y (4) grupo placebo - GP. El umbral doloroso fue determinado por medio de un algómetro antes (T1), luego después (T2) y en los instantes 10 (T3), 20 (T4) y 30 (T5) minutos después de la aplicación de las técnicas de analgesia. La TENS (100 Hz, 40 μs) y la crioterapia (compresa fría) fueron aplicadas durante 20 minutos en el GC, GT y GCT, mientras que en el GP fue simulada la electroestimulación por el mismo período. Un ANOVA para medidas repetidas y el test post hoc de Bonferroni fueron utilizados en los analices, considerando un 5% de nivel de significancia. Todos los grupos experimentales presentaron aumento en el umbral doloroso al compararlos al GP: GC (p<0,001), GT (p<0,009) y GCT (p<0,008). Con relación al tiempo de analgesia, se observó un aumento del umbral doloroso en T2 para todos los grupos experimentales (p<0,001) hasta T3 para el GCT (p<0,001) y solamente en el GC la analgesia prosiguió hasta T5. Se concluyó que en las condiciones estudiadas, los tres grupos experimentales tuvieron un aumento en el umbral doloroso comparado al GP, pero la crioterapia tuvo un efecto más longo.

Estudos têm demonstrado que a crioterapia, a estimulação elétrica nervosa transcutânea (TENS) e a associação destas promovem analgesia, porém a efetividade dessa associação não está clara. Objetivou-se avaliar os efeitos da aplicação isolada e associada da TENS e da crioterapia sobre o limiar de dor induzida por pressão em sujeitos saudáveis. A amostra constou de 40 sujeitos, designados aleatoriamente em quatro grupos: (1) grupo crioterapia - GC; (2) grupo TENS - GT; (3) grupo crioterapia + TENS - GCT; e (4) grupo placebo - GP. O limiar doloroso foi determinado por meio de um algômetro antes (T1), imediatamente após (T2) e nos instantes 10 (T3), 20 (T4) e 30 (T5) minutos após a aplicação das técnicas de analgesia. A TENS (100 Hz, 40 μs) e a crioterapia (compressa fria) foram aplicadas durante 20 minutos em GC, GT e GCT, enquanto no GP foi simulada a eletroestimulação pelo mesmo período de tempo. Uma ANOVA para medidas repetidas e o teste post hoc de Bonferroni foram utilizados nas análises, considerando nível de significância de 5%. Todos os grupos experimentais apresentaram aumento no limiar doloroso quando comparados ao GP: GC (p<0,001), GT (p<0,009), e GCT (p<0,008). Em relação ao tempo da analgesia, observou-se aumento do limiar doloroso em T2 para todos os grupos experimentais (p<0,001), até T3 para o GCT (p<0,001) e apenas no GC a analgesia se prolongou até o T5. Concluiu-se que nas condições estudadas, os três grupos experimentais tiveram um aumento no limiar doloroso comparado ao GP, porém a crioterapia teve o efeito mais prolongado.

Effectiveness of low level laser therapy in the treatment of TMD myalgia: two case reports / Eficácia do laser de baixa potência no tratamento da DTM: dois relatos de casos

Objective: To report two cases of low level laser therapy used in the treatment of muscle pain caused by temporomandibular disorders (TMDs). Methods: Two patients were selected and subjected to eight applications of low level laser therapy (diode - wavelength of 795 nm, energy density of 8 J/cm2, power of 120 mW, 66 se per point). Laser was punctually applie on masseter and temporalis muscles bilaterally. Three methods were used to evaluate the effectiveness of treatment: pressure algometer, visual analog scale (VAS) and maximal mouth opening. Each measurement was performed before and after the laser therapy session. The results were subjected to statistical analysis (ANOVA two factors and Tukey’s test, α = 0.05). Results: For both patients, no significant difference was found between the results obtained with the algometer, before and after laser application, within each session. VAS results showed a tendency to lower values after laser application. In both cases, the highest values obtained by the pressure algometer were found between the days 9 (fourth application) and 16 (sixth application). Both patients had an improvement on mouth opening. Conclusions: The assessment methods used were quite practical to register the pain before and after treatment. Therapy with low level laser seems to have a beneficial effect for the masticatory muscles pain.

Objetivo: relatar dois casos do uso do laser de baixo potência no tratamento da dor muscular causada pela disfunção temporomandibular (DTM). Métodos: Dois pacientes foram selecionados e submetidos a oito aplicações de laser de baixa potência (diodo - comprimento de onda de 795 nm, densidade de energia de 8 J/cm2, potência de 120 mW, 66 segundos por ponto). O laser foi aplicado pontualmente nos músculos masseter e temporal bilateralmente. Três métodos foram utilizados para avaliar a eficácia do tratamento: algômetro de pressão, escala visual analógica (VAS) e abertura máxima da boca. Cada medição foi realizada antes e após a sessão de terapia com laser. Os resultados foram submetidos à análise estatística (ANOVA dois fatores e teste de Tukey, α= 0,05). Resultados: Em ambos os casos, não foi encontrada diferença significativa entre os resultados obtidos com o algômetro antes e depois da aplicação do laser dentro de cada sessão. Os resultados com o VAS mostraram uma tendência a reduzir os valores após a aplicação do laser. Foram encontrados os maiores valores obtidos pelo algômetro de pressão entre os dias 9 (quarta aplicação) e 16 (sexta aplicativo), em ambos os casos. Ambos os pacientes tiveram uma melhora na abertura da boca. Conclusões: Os métodos de avaliação utilizados foram bastante prático para registrar a dor antes e após o tratamento. A terapia com laser de baixa potência parece ter um efeito benéfico para a dor músculos mastigatórios

Reliability and Usefulness of the Pressure Pain Threshold Measurement in Patients with Myofascial Pain

OBJECTIVE: To assess the usefulness of a pressure algometer to measure pressure pain threshold (PPT) for diagnosis of myofascial pain syndrome (MPS) in the upper extremity and trunk muscles. METHOD: A group of 221 desk workers complaining of upper body pain participated in this study. Five physiatrists made the diagnosis of MPS using physical examination and PPT measurements. PPT measurements were determined for several muscles in the back and upper extremities. Mean PPT data for gender, side, and dominant hand groups were analyzed. Sensitivity and specificity of Fischer's standard method were evaluated. PPT cut-off values for each muscle group were determined using an ROC curve. RESULTS: Cronbach's alpha for each muscle was very high. The PPT in men was higher than in females, and the PPT in the left side was higher than in the right side for all muscles tested (p<0.05). There was no significant difference in PPT for all muscles between dominant and non-dominant hand groups. Diagnosis of MPS based on Fischer's standard showed relatively high specificity and poor sensitivity. CONCLUSION: The digital pressure algometer showed high reliability. PPT might be a useful parameter for assessing a treatment's effect, but not for use in diagnosis or even as a screening method.

Interference of age and repetition of the same noxious stimulus on hyperalgesia / Interferência da idade e repetição do mesmo estímulo doloroso na hiperalgesia

Pain in animals has been recognized for less than one century. Several authors confirm that animals are capable to process, register and modulate nociceptive stimuli in a very similar way to human kind and there are several evidences registering the impact of pain sensation over vital systems interfering on disease outcome. Nevertheless, despite some evidences that animals, as human beings, can store information from past painful experiences less is known about how this so called pain memory works. The aims of this study were: to evaluate if the response to a painful stimuli differs during different stages of life and if repetition of a same acute stimuli in the same animal interferes with expression of hyperalgesia. Thus, 60 rats were selected and arranged in 3 equal groups: 3 months, 6 months, and 9 months of age. All animals were injected 5 percent formalin solution in the plantar face of hind paw under volatile general anesthesia. Von Frey filaments were applied at 1h, 24h and 48h after sensitization. Injection was repeated twice with a 30-day interval, each time in a different hind paw. Results showed that younger rats express lower hyperalgesia thresholds in the first stimulation compared to elder animals and that repetition of same stimulus diminishes hyperalgesia thresholds when it begins during infant period and augments hyperalgesia thresholds when it begins during elder ages.

A dor nos animais tem sido reconhecida há pouco manos de um século. Vários autores reconhecem que os animais são capazes de processar, registrar e modular estímulos nociceptivos de modo muito similar aos seres humanos e há várias evidências registrando o impacto da sensação dolorosa sobre os sistemas vitais e curso da doença. Entretanto, a despeito das evidências de que os animais, como os seres humanos, podem armazenar informações passadas de experiências dolorosas pouco se sabe sobre como a chamada memoria de dor funciona. Os objetivos deste estudo foram: avaliar se a resposta a um estímulo doloroso difere em diferentes fases da vida e se a repetição de um mesmo estímulo doloroso agudo no mesmo animal interfere na expressão da hiperalgesia. Assim, 60 ratos foram selecionados e agrupados em três grupos iguais: 3 meses, 6 meses e 9 meses. Foi injetada solução de formalina 5 por cento na face plantar de todos os animais durante anestesia. O limiar de hiperalgesia foi testado pelo método de filamentos de Von Frey à 1h, 24h e 48h após a sensibilização. A injecão foi repetida duas vezes com intervalo de 30 dias, uma vez em cada membro. Os resultados demonstraram que animais mais jovens possuem limiares menores de hiperalgesia na primeira estimulação, comparados com os mais velhos e que a repetição de um mesmo estímulo doloroso agudo diminui o limiar de hiperalgesia quando o primeiro estímulo ocorre nas idades mais tenras e aumenta o limiar quando se inicia em idades mais avançadas.

Reliability and validity of the hand-held pressure algometer as a measuring instrument of pressure pain threshold / 中华物理医学与康复杂志

Objective To evaluate the test-retest and inter-rater reliability of the hand-held pressure algometer as a measuring instrument of pressure pain threshold(PPT).Method A total of 37 healthy subjects were recruited for reliability test.Three raters measured the PPT at 12 body sites of the subjects.Each rater conducted three trials on each site.In the validity test,10 patients with active trigger points in the upper trapezius were recruited and measured by one rater using the pressure algometer for PPT,the visual analogue scale(VAS)was also used to evaluate the pain intensity induced by the trigger point.The intraclass correlation coefficient and Spearman correlation coefficient were calculated to reflect the reliability and validity.Results The test-retest and inter-rater reliabilities were both high(ICC＞0.95),with the measurements by one rater were more reliable than measurements by multiple raters.The inter-rater reliability of PPT measurement obtained by using the mean value of 3 trials was higher than any of the 3 trials alone.The PPT values of the trigger points were higher than those of the normal points,and there was a significantly negative correlation between the PPT values of the trigger points and the VAS scores.Conclusion The intra-and inter-rater PPT measurements in healthy subjects obtained with the hand-held pressure algometer were highly reliable.The algometer was valid for quantifying myofascial trigger point sensitivity.

Usefulness of Electronic Pressure Algometer in Evaluation of Pressure Pain Threshold in Normal Korean Adults

OBJECTIVE: To examine pressure pain threshold (PPT) on several skeletal muscles in upper extremity, trunk, and lower extremity by using electronic pressure algometer and to evaluate it's interrater reliability, reproducibility, difference between gender and dominance, correlation with body mass index, and comparison among each muscles. METHOD: Forty healthy adults (male 27, female 13) were examined by two raters and reexamined in the same order after a rest of 10 minute. PPT at the splenius capitis, upper trapezius, infraspinatus, lumbar paraspinal muscle, extensor carpi radialis, vastus medialis, and gluteus medius muscles of both side was measured by medical electronic algometer. Rate of force application was approximately 2 lb/sec. Body mass index (BMI) was estimated from the individual's body weight by the square of their height. RESULTS: There were no statistical differences of PPTs at all muscles between two raters, between two test with time interval, and between dominant and nondominant side, respectively. PPT in man was higher than female at all muscles. There was significant correlation between BMI and PPT at lumbar paraspinal muscle, vastus medialis, and gluteus medius only in male. PPT was highest at lumbar paraspinal muscle and lowest at splenius capitis. CONCLUSION: Electronic pressure algometer is a reliable tool for evaluation of PPT which has high interrater reliability and high reproducibility and is not affected by dominance and location of muscles. Therefore, it is a useful clinical tool to compare PPT before and after treatment and to study the mechanism of musculoskeletal pain research program.