Terkelsen A J, Andersen O K, Mølgaard H, Hansen J, Jensen T S
Department of Neurology and Danish Pain Research Center, Aarhus University Hospital, Aarhus, Denmark.
Acta Physiol Scand. 2004 Apr;180(4):405-14. doi: 10.1111/j.1365-201X.2004.01263.x.
Do distraction from- or attention to sural nerve stimulation affect pain, heart rate variability, and a spinal withdrawal reflex?
In 26 male volunteers, electrical stimulation at the distal cutaneous receptive field of the sural nerve elicited pain and a nociceptive withdrawal reflex. Intensity of pain was rated on a numeric rating scale. Electromyographic reflex responses were measured from biceps femoris muscle. Cardiac autonomic function was estimated by heart rate variability measures and was expressed in the time domain as mean of RR-intervals for normal heart beats (mean-RR) and standard deviation of all normal RR-intervals (SD-NN) and, in the frequency domain, where pure vagal activity was assessed by high frequency power (0.15-0.4 Hz). Low frequency power (0.04-0.15 Hz) reflects both parasympathetic and sympathetic control. Effect parameters were recorded before and during random distraction and attention. Distraction from sural nerve stimulation was induced by a mental arithmetic test, paced auditory serial addition task (PASAT), while attention was induced by concentrating on painful foot stimulation.
Paced auditory serial addition task decreased mean-RR and SD-NN, frequency domain parameters, as well as pain (P<0.001). In contrast, PASAT did not change the spinal withdrawal reflex. Attention did not affect any effect parameter.
Distraction by PASAT altered autonomic activity and inhibited pain but failed to affect withdrawal reflex responses, while attention had no effect on either parameter. Psychological distraction and attention may have different effects on noxious evoked pain perception and autonomic activity. Pain relief during PASAT probably involves supraspinal mechanisms.
对腓肠神经刺激的注意力分散或集中是否会影响疼痛、心率变异性和脊髓退缩反射？
在26名男性志愿者中，对腓肠神经远端皮肤感受野进行电刺激可引发疼痛和伤害性退缩反射。疼痛强度采用数字评分量表进行评定。从股二头肌测量肌电图反射反应。通过心率变异性测量评估心脏自主神经功能，在时域中以正常心跳的RR间期平均值（平均RR）和所有正常RR间期的标准差（SD-NN）表示，在频域中，通过高频功率（0.15 - 0.4 Hz）评估纯迷走神经活动。低频功率（0.04 - 0.15 Hz）反映副交感神经和交感神经的控制。在随机的注意力分散和集中之前及期间记录效应参数。通过心算测试、听觉连续加法任务（PASAT）诱导对腓肠神经刺激的注意力分散，而通过专注于足部疼痛刺激诱导注意力集中。
听觉连续加法任务降低了平均RR、SD-NN、频域参数以及疼痛（P<0.001）。相比之下，PASAT并未改变脊髓退缩反射。注意力集中未影响任何效应参数。
PASAT引起的注意力分散改变了自主神经活动并抑制了疼痛，但未能影响退缩反射反应，而注意力集中对这两个参数均无影响。心理上的注意力分散和集中可能对伤害性诱发的疼痛感知和自主神经活动有不同影响。PASAT期间的疼痛缓解可能涉及脊髓上机制。
