De Benedittis G
Institute of Neurosurgery, University of Milan, Italy.
J Neurosurg Sci. 1987 Jul-Sep;31(3):109-19.
Clinical evidence shows that pain, particularly without organic lesions, tends to be more frequent on the left side of the body. Concomitantly, experimental data indicate that differential sensitivity for the right and left side, the pain threshold and tolerance being usually higher in the dominant than in the non-dominant side of the body. Headache laterality was investigated in 188 consecutive chronic headache patients. Headache was lateralized in approximately 50% of the cases, with an overall right predominance (59%). However, when descriptive diagnosis was taken into consideration, lateralized pain was predominant on the left side in psychogenic headache (p less than .01), whereas somatogenic headache was more often right-sited. Since pain lateralization can hardly be explained by peripheral factors, we assumed that reduced efficiency of the non-dominant side in processing several perceptual and cognitive activities could reflect asymmetry in cerebral organization. As differential engagement of the two hemispheres by appropriate tasks can be demonstrated with the EEG, we have studied 13 chronic headache patients with quantitative EEG analysis, compared with a control group of normal subjects (n = 7). The analysis of alpha-asymmetry, during analytical and spatial tasks, revealed that chronic headache patients showed a trend toward a relative activation of the right hemisphere during both tasks, independently of descriptive diagnosis, suggesting that chronic headache might be considered a "psychosomatic continuum". We postulate that pain perception may be biased by the reduced efficiency of the right hemisphere in sensory processing, so that the sensory message may be misinterpreted or amplified as painful by higher centers, even in absence of nociceptive stimuli.
临床证据表明，疼痛，尤其是无器质性病变的疼痛，往往在身体左侧更为常见。与此同时，实验数据表明，身体左右两侧的敏感性存在差异，优势侧的疼痛阈值和耐受性通常高于非优势侧。对188例连续性慢性头痛患者的头痛偏侧性进行了研究。约50%的病例头痛呈偏侧性，总体上以右侧为主（59%）。然而，考虑到描述性诊断时，心因性头痛中左侧偏侧性疼痛占主导（p<0.01），而躯体性头痛更多位于右侧。由于疼痛偏侧化很难用外周因素来解释，我们推测非优势侧在处理多种感知和认知活动时效率降低可能反映了大脑组织的不对称性。由于通过脑电图可以证明适当任务对两个半球的不同参与情况，我们对13例慢性头痛患者进行了定量脑电图分析研究，并与7名正常受试者的对照组进行了比较。在分析性和空间性任务期间对α波不对称性的分析表明，慢性头痛患者在两项任务中均呈现右半球相对激活的趋势，与描述性诊断无关，这表明慢性头痛可能被视为一种“身心连续体”。我们推测，疼痛感知可能因右半球感觉处理效率降低而产生偏差，以至于即使在没有伤害性刺激的情况下，感觉信息也可能被高级中枢错误解读或放大为疼痛。
