Blomhoff S, Spetalen S, Jacobsen M B, Malt U F
Department of Psychosomatic and Behavioral Medicine, National Hospital, Oslo, Norway.
Psychosom Med. 2001 Nov-Dec;63(6):959-65. doi: 10.1097/00006842-200111000-00015.
Disease severity in the irritable bowel syndrome (IBS) is highly influenced by psychiatric comorbidity. The mechanism of this influence is generally unknown, even if the brain-gut axis seems to be involved. Recent research has indicated that IBS patients have aberrant perception of visceral stimuli in the CNS. We compared IBS patients with and without comorbid phobic anxiety to see if the comorbid disorder influenced brain information processing of auditory stimuli, and looked for possible consequences with respect to visceral sensitivity thresholds and disease severity.
Eleven female patients with IBS with comorbid phobic anxiety disorder were compared with 22 age-matched female IBS patients without such comorbidity. The groups were compared with respect to event-related potentials (ERP), auditory-presented words with emotional contents, barostat-assessed visceral sensitivity thresholds, and symptom levels the last week before assessment.
The comorbid group had a significantly enhanced first negative ERP wave (N1) to all stimuli, indicating increased use of brain attentional resources. It also had increased visceral threshold for the sensation of gas, and reduced gas-stool and gas-discomfort tolerances compared with the noncomorbid group. Enhanced N1 amplitude at the frontal electrode and reduced gas-stools tolerance significantly predicted subjective gas complaints, explaining 47% of the symptom variation.
The study suggests an association between information processing in the frontal brain and visceral sensitivity characteristics in IBS patients, and indicates that subjective disease-related symptomatology is predicted by brain perceptual characteristics. The findings indicate that an interaction between IBS-related and anxiety-related hyperreactivity in the frontal brain may constitute a psychophysiological mechanism for the contribution of psychiatric comorbidity to severity and duration of the irritable bowel syndrome.
肠易激综合征（IBS）的疾病严重程度受精神共病的影响很大。即使脑-肠轴似乎与之相关，这种影响的机制通常仍不清楚。最近的研究表明，IBS患者在中枢神经系统中对内脏刺激存在异常感知。我们比较了伴有和不伴有共病性恐惧焦虑的IBS患者，以观察共病是否会影响听觉刺激的脑信息处理，并寻找其对内脏敏感性阈值和疾病严重程度的可能影响。
将11名患有共病性恐惧焦虑障碍的女性IBS患者与22名年龄匹配的无此类共病的女性IBS患者进行比较。比较两组在事件相关电位（ERP）、呈现带有情感内容的听觉单词、通过气压监测评估的内脏敏感性阈值以及评估前最后一周的症状水平。
共病组对所有刺激的第一个负向ERP波（N1）显著增强，表明大脑注意力资源的使用增加。与非共病组相比，其对气体感觉的内脏阈值也有所增加，对气体-粪便和气体不适的耐受性降低。额电极处增强的N1波幅和降低的气体-粪便耐受性显著预测了主观气体不适，解释了47%的症状变异。
该研究表明IBS患者额叶脑区的信息处理与内脏敏感性特征之间存在关联，并表明主观疾病相关症状可由脑感知特征预测。研究结果表明，额叶脑区中IBS相关和焦虑相关的反应过度之间的相互作用可能构成了精神共病对肠易激综合征严重程度和病程产生影响的心理生理机制。
