重新思考其他ADHD亞型分類方式：檢驗ADHD-PI次亞型獨特的認知神經功能缺失

Abstract

注意力不足過動症（Attention Deficit Hyperactivity Disorder, ADHD）是常見的發展疾患，具有症狀異質性高的特徵，依照過動衝動、注意力缺失症狀的嚴重程度被分成三種亞型。過去的學者認為ADHD的亞型分類方式缺乏區辨效度，可能與注意力不足為主型（Predominantly inattentive type, ADHD-PI）存在內部異質性過高有關。如果未將ADHD-PI再分類，解決異質性高的問題，可能混淆後續研究結果與治療效果，形成錯誤的結論。精神疾病診斷與統計手冊第五版的編輯委員會最初也提出將ADHD-PI再區分亞型，但這項決議最終仍以實證研究不足為由刪除，並鼓勵後進學者補充關於ADHD-PI次亞型特有的認知神經功能障礙的證據（或稱生物標記）。此外，近年一些研究報告了患有注意力問題的患者大致可歸納為兩類，第一類的注意力不足患者幾乎沒有過動衝動的症狀，甚至是過度不活動，另一類的注意力不足患者則是具有過動衝動的症狀，除了過動衝動程度的差異，兩群人的注意力問題型態似乎也不同，沒有過動衝動症狀的患者具有高緩慢的認知風格（Sluggish cognitive tempo, SCT） 注意力問題，具有過動衝動的患者則少有高緩慢的認知風格問題，而是分心問題（distractibility）。因此，有些學者利用過動衝動症狀程度將ADHD-PI再區分成近無過動衝動症狀的ADHD嚴格限制注意力問題型（Restrictive inattentive type, ADHD-RI），以及中度過動衝動症狀的ADHD非嚴格限制注意力問題型（None restrictive inattentive type, ADHD-NRI），也有些學者是利用緩慢的認知格高低將ADHD-PI區分成PI+HSCT （PI and high SCT）、PI+LSCT（PI and low SCT）。雖然傳統觀點認為這兩種分類方式應該相同，但近期仍有不一致的結果，尚需再次檢驗。本研究目的在評估注意力不足為主型的次亞型獨有的認知神經功能障礙，並且檢驗以「過動衝動量」所區分得出的兩個注意力缺失為主型的次亞型，是否等同於以「緩慢的認知風格」做區分所得出的兩個注意力缺失為主型的次亞型。本研究選用經精神科醫師評估的兒童，主要分成正常控制組、ADHD-C、ADHD-PI。藉由過動衝動量將ADHD-PI分成ADHD-RI、ADHD-NRI，以及藉由緩慢的認知風格將ADHD-PI分成PI+HSCT、PI+LSCT。首先以卡方檢定檢驗兩種分類方式是否相同，接著以劍橋神經心理評估系統（CANTAB）作為認知神經功能評估工具，先比較正常控制組、ADHD-C、ADHD-RI、ADHD-NRI的差異，再比較正常控制組、ADHD-C、PI+HSCT、PI+LSCT的差異。結果顯示這兩種ADHD-PI的分類方式並不相同。在認知神經功能方面，四組注意力缺失為主型的亞型均有獨特但不同的認知神經功能障礙。這些發現意味著在未來的治療或研究中有必要特別區分出ADHD-PI的次亞型，以找出更精確的病理機制與最佳治療策略。

Attention-deficit hyperactivity disorder (ADHD) is a common developmental disorder, which has high heterogeneity in symptoms. According to the severity in core symptoms, there are three subtypes. Researcher indicated that the classification of ADHD subtypes was lack of discriminant validity, it might be due to the high internal heterogeneity of the Predominantly inattentive type(ADHD-PI). If it didn’t classified the ADHD-PI again, and solved the high heterogeneity, it could confuse the following researchers and the treatment effects, resulting in a wrong conclusion in the end. The editorial board of DSM-5 initially suggested to classify the ADHD-PI into subgroups; however, the last few meetings removed it for its lack of existing empirical research result, and also encourage those late researchers to complement the evidence of the distinctive neurocognitive profiles of ADHD-PI subgroups. Additionally, in recent years, some researchers reported that these patients with attention problems could be approximately classified into two categories. Some ADHD-PI patients are hyperactive/impulsive and some lack this trait altogether. Furthermore, each of these groups appear to differ in their attention problem type. Patients without hyperactivity/impulsivity had the attention problem of “sluggish cognitive tempo,”(SCT), while patients with hyperactivity/impulsivity showed less of a tendency to exhibit this problem. Therefore, some researchers used the level of hyperactivity/impulsivity to distinguish the ADHD-PI into Restrictive inattentive type(ADHD-RI)which showed bare symptom of hyperactivity/impulsivity and None restrictive inattentive type(ADHD-NRI)with moderate symptom of hyperactivity/impulsivity. Meanwhile, some researchers used the level of sluggish cognitive tempo to distinguish the ADHD-PI into PI+HSCT(PI and high SCT)and PI+LSCT(PI and low SCT).These two classifications should be the same that based on the traditional perspective, but there are still inconsistent results in and they need to be tested again. Our purpose is to assess neurocognitive profiles which ADHD-PI subgroups have, and test whether two subgroups categorized by the level of hyperactivity/impulsivity, is equivalent to two subgroups categorized by the level of SCT. In this study, children assessed by the psychiatrists were divided into groups, including typical developing control, ADHD-C, ADHD-PI. According to the level of hyperactivity/impulsivity to distinguish the ADHD-PI into ADHD-RI and ADHD-NRI and meanwhile according to level of SCT to distinguish the ADHD-PI into PI+HSCT and PI+LSCT. First, use the chi-square to test whether these two classifications are the same, and the use CANTAB as the measurement of neurocognitive function. To find out the difference on neurocognitive function, we compared the difference among TD, ADHD-C, ADHD-RI and ADHD-NRI, and then compared the difference among TD, ADHD-C, PI+HSCT, PI+LSCT. Results suggested that these two classification of ADHD-PI are different. All four ADHD-PI subgroups uniquely differ in their neurocognitve profiles. These findings suggest that it is necessary to distinguish ADHD-PI subgroups in future treatments or studies to find more precise pathological mechanisms and optimal treatment strategies.