Effects of specific hypnotic suggestions on mechanical and thermal sensitivity of healthy volunteers: randomized and double-blind study / Efeito de sugestões hipnóticas específicas sobre a nocicepção mecânica e térmica em voluntários saudáveis: estudo randomizado e duplo-cego

ABSTRACT BACKGROUND AND OBJECTIVES: Hypnotic suggestions for hypoalgesia or analgesia are efficient for relieving different pain conditions, presenting few or no side effects. However, little is known about its direct effect on the modulation of peripheral nociception. The goal of this study was to evaluate the mechanical and thermal response after specific hypnotic suggestions in healthy volunteers. METHODS: This is a randomized double-blinded controlled trial that aimed to evaluate both mechanical and thermal nociception after specific hypnotic suggestions in healthy volunteers. For this, twenty-seven participants were enrolled, according to the following eligibility criteria: age between 18-65 years and absence of pain complaints or psychological disorders. After signed Free Informed Consent Term (FICT) the participants were divided by a computer-generated randomization in three groups: sham group (no induction of hypnosis), hypnosis-induced pain group and hypnosis-induced analgesia group. Susceptibility to hypnosis was assessed through the Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility and outcomes included evaluation of questionnaires (Hospital Anxiety and Depression Scale and Short Form Brief Pain Inventory) as well as the examination of mechanical and thermal nociception through the Quantitative Sensory Testing (QST), a tool widely used to investigate somatosensory sensitivity by assessing functions of small A-δ and C nerve sensory fibers, before and after specific hypnotic suggestion for pain and analgesia made by a qualified hypnotherapist. RESULTS: Data demonstrated that specific hypnotic suggestions induced significant changes in mechanical and thermal sensitivity. The pain group revealed an increase in mechanical hyperalgesia and allodynia, while the analgesia group increased pain thresholds to thermal stimulations, being conditioned to withstand temperature changes after hypnosis, demonstrating a modulatory effect for both pain and analgesia sensations in healthy volunteers. CONCLUSION: The evidence presented in this study supports the use of the hypnosis technique as an auxiliary tool in clinical practice. HIGHLIGHTS Specific hypnotic suggestions can modulate peripheral nociception in healthy subjects. Data show a modulatory effect for both pain and analgesia sensations. Hypnosis can be considered a feasible technique for the clinical pain management.

RESUMO JUSTIFICATIVA E OBJETIVOS: Sugestões hipnóticas de hipoalgesia ou analgesia são eficientes para aliviar diferentes quadros álgicos, apresentando poucos ou nenhum efeito colateral. No entanto, pouco se sabe sobre seu efeito direto na modulação da nocicepção periférica. O objetivo deste estudo foi avaliar a resposta mecânica e térmica após sugestões hipnóticas específicas em voluntários saudáveis. MÉTODOS: Este é um estudo randomizado e duplo-cego que visou avaliar a nocicepção mecânica e térmica após sugestões hipnóticas específicas em voluntários saudáveis. Para isso, vinte e sete participantes foram selecionados, de acordo com os seguintes critérios de elegibilidade: idade entre 18 e 65 anos e ausência de distúrbios psicológicos e de queixas de dor. Após a assinatura do Termo de Consentimento Livre e Esclarecido (TCLE), os participantes foram divididos por randomização gerada por computador em três grupos: grupo sham (sem indução de hipnose), grupo dor induzida por hipnose e grupo analgesia induzida por hipnose. A suscetibilidade à hipnose foi avaliada através da escala Waterloo-Stanford Group C (WSGC) de suscetibilidade hipnótica e os resultados incluíram a avaliação de questionários (Escala Hospitalar de Ansiedade e Depressão e Inventário Breve de Dor), bem como o exame de nocicepção mecânica e térmica através do Teste Sensorial Quantitativo (QST), uma ferramenta amplamente utilizada para investigar a sensibilidade somatossensorial por meio da avaliação das funções das fibras sensoriais finas dos nervos A-δ e C, antes e após sugestão hipnótica específica para dor e analgesia aplicada por um hipnoterapeuta qualificado. RESULTADOS: Os dados mostraram que as sugestões hipnóticas específicas induziram mudanças significativas na sensibilidade mecânica e térmica dos indivíduos. O grupo dor revelou aumento da hiperalgesia mecânica e da alodinia, enquanto o grupo analgesia aumentou os limiares de dor por estímulos térmicos, sendo condicionado a suportar mudanças de temperatura após a hipnose, demonstrando efeito modulador tanto para as sensações de dor quanto de analgesia em voluntários saudáveis. CONCLUSÃO: As evidências apresentadas neste estudo sustentam o uso da técnica de hipnose como ferramenta auxiliar na prática clínica. DESTAQUES Sugestões hipnóticas específicas podem modular a nocicepção periférica em sujeitos saudáveis. Os dados mostram um efeito modulador tanto para as sensações de dor quanto de analgesia. A hipnose pode ser considerada uma técnica viável para o manejo clínico da dor.

Analysis of nerve conduction velocity and quantitative sensory test in patients with early diabetic peripheral neuropathy / 中国医师进修杂志

Objective To observe the characteristics of electro-neurophysiology in diabetic patients with early peripheral neuropathy. Method The nerve conduction velocity ( NCV ) and quantitative sensory test (QST) were examined in 175 diabetic patients without clinical peripheral neuropathy and in 50 normal subjects, and their results were compared. Results In 175 diabetic patients, the abnormal ratio of NCV was 7% (13/175).While using QST,the abnormal ratio was 45% (79/175). There was significant difference between two methods (P< 0.01). Compared diabetic patients with normal subjects,there was no significant difference between motor conduction velocity and sensory conduction velocity (P > 0.05 ).While using QST, the threshold values of cold sensation, warm sensation, and thermalgesia showed significant difference between diabetic patients and normal subjects (P< 0.01). Conclusion QST is more sensitive than NCV in diagnosing diabetic peripheral neuropathy, which suggests that small nerve fibers are more likely to be damaged than large fibers in early stage.

Evaluation of Peripheral Polyneuropathy in Patients with Diabetes Mellitus Using Quantitative Sensory Test

OBJECTIVE: The purpose of this study was to determine whether quantitative sensory test can be used as a screening test of peripheral polyneuropathy in patients with diabetes mellitus, and to evaluate the severity of peripheral polyneuropathy in patients with diabetes mellitus using quantitative sensory test. METHOD: We performed nerve conduction study to right upper and left lower extremity of the patients. Quantitative sensory test was performed using TSA-2001 thermal sensory analyser on right thenar and left foot dorsum in both diabetic and control groups. RESULTS: 1) The warm sense and heat pain threshold were higher, the cold sense and cold pain threshold were lower in diabetic group than age-matched control group (p<0.05). 2) The warm sense and heat pain threshold were higher, the cold sense and cold pain threshold were lower in diabetic group than young-aged control group (p<0.05). 3) As nerve conduction study results were severe, the cold sense threshold in right thenar were decreased (p<0.05). CONCLUSION: Quantitative sensory study in patients with diabetes mellitus are sensitive to identify neuropathic change; thus, they would be used as the screening method of diabetic peripheral polyneuropathy.

Quantitative Sensory Test in Normal Adult

OBJECTIVE: To obtain normal data of quantitative sensory test (QST) in Korean adult. METHOD: The subjects were 85 normal adults aging from 30 to 69 years old, who had no abnormal sensory and neurologic problem. We performed following three QSTs on dominant side and one verbal questionnaire. 1) Semmes-Weinstein monofilament wire system (0.05 G, 0.2 G, 2 G, 4 G, 10 G, 300 G) for touch sensation, 2) Rydel-Seiffer Tuning Fork for vibration sensation, 3) TSA-2001 Thermal sensory analyser for thermal sensation, 4)University of Texas Subjective Peripheral Neuropathy verbal questionnaire. RESULTS: 1) Touch perception score measured with Semmes-Weinstein monofilament wire system, declined with age (p<0.01). 2) Vibration perception score measured with the tuning fork, declined with age in foot (p<0.01). 3) Warm sense and heat pain threshold measured with TSA-2001 thermal sensory analyser increased with age, and cold sense and cold pain threshold declined with age. 4) Weight showed negative correlation with vibration perception score in man's foot. CONCLUSION: Normal data of three sensory test obtained from this study could be used for the early detection of peripheral neuropathy or loss of "protective sensation".

Diagnostic Usefulness of Quantitative Sensory Test in Diabetic Polyneuropathy: Comparison with Nerve Conduction Study

BACKGROUND: Although nerve conduction study(NCS) is useful to diagnose diabetic neuropathy, it is still difficult to define objectively the presence or absence of neuropathy in patients with diabetes mellitus. Results of NCS mainly reflect the function of large myelinated nerve fibers, and sometimes reveal no abnormality even in patients with objective signs or subjective sensory symptoms. Recently, a new diagnostic approach, quantitative sensory test (QST) was introduced and exploited for diagnosis of diabetic neuropathy. The objective of this study is to compare the sensitivities of two tests, QST and NCS. METHODS: We evaluated the sensory thresholds of QST in 22 normal controls (group 1) and 26 diabetic patients. The diabetic patients were divided into two groups, 11 patients without symptomatic diabetic polyneuropathy(group 2) and 15 patients with symptomatic diabetic polyneuropathy(group 3). We evaluated warm (WDT), cooling (CDT), heat-pain (HPDT) and vibration (VDT) detection thresholds in all three groups with computer-assisted sensory examination system (CASE IV). We also did NCS in group 2 and 3. The diagnostic value of QST was compared with NCS. RESULTS: In group 1, the CDT, WDT, VDT and HPDT were 7.3, 9.9, 8.7, and 17.2 JND on hand, and 11.6, 15.3, 13.9 and 17.8 JND on foot respectively. On foot, the CDT and WDT of group 3 were different from that of group 1 and 2, and the VDT of group 3 was different from that of group 1. However, no other sensory thresholds on hand and foot were different significantly among three groups. The diagnostic specificity of QST was similar to NCS and the diagnostic sensitivity was slightly lower than NCS without statistical significance. CONCLUSIONS: We measured sensory thresholds in normal and diabetic patients, and concluded that the QST might be complement to NCS for early detection of diabetic polyneuropathy.

Quantitative sensory analysis of anxiety neurosis / 重庆医科大学学报

Objective:To investigate the characteristics of quantitative sensory test(QST) in anxiety neurosis patients and to evaluate the effect of anti-anxiety treatment.Methods:30 anxiety neurosis patients with subjective sensory disturbance,20 diabetes patients and 46 health controls were chosen.Each person's thermal thresholds of both left and right thenar and instep were tested.The results of QST were compared among each other.Results:The thermal thresholds of the patients with anxiety neruosis were lower than those of the patients with diabetes and healthy controls( P