Patients with attention deficit/(hyperactivity) disorder (AD(H)D) show increased intra-individual variability (IIV) in behavioral performance. This likely reflects dopaminergic deficiencies. However, the precise performance profile across time and the pattern of fluctuations within it have not yet been considered, partly due to insufficient methods. Yet, such an analysis may yield important theory-based implications for clinical practice. Thus, in a case-control cross-sectional study, we introduce a new method to investigate performance fluctuations in patients with ADD (n = 76) and ADHD (n = 67) compared to healthy controls (n = 45) in a time estimation task. In addition, we also evaluate the effects of methylphenidate (MPH) treatment on this performance pattern in 29 patients with AD(H)D. Trial-by-trial differences in performance between healthy controls and patients with AD(H)D do not persist continuously over longer time periods. Periods during which no differences in performance between healthy controls and patients occur alternate with periods in which such differences are present. AD(H)D subtype and surprisingly also medication status does not affect this pattern. The presented findings likely reflect (phasic) deficiencies of the dopaminergic system in patients with AD(H)D which are not sufficiently ameliorated by first-line pharmacological treatment. The presented findings carry important clinical and scientific implications.

中文翻译：

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ADHD内个体表现差异的新颖方法。

有注意缺陷/（多动）障碍（AD（H）D）的患者表现出个体内行为变异（IIV）增加。这可能反映了多巴胺能缺陷。但是，尚未考虑跨时间的精确性能概况及其内的波动模式，部分原因是方法不足。但是，这种分析可能会对临床实践产生重要的基于理论的启示。因此，在病例对照横断面研究中，我们引入了一种新方法来研究与健康对照（n = 45）相比ADD（n = 76）和ADHD（n = 67）与ADHD（n = 67）患者的性能波动任务。此外，我们还评估了29例AD（H）D患者的哌醋甲酯（MPH）治疗对这种表现模式的影响。健康对照与AD（H）D患者之间的逐项试验差异不会持续较长时间。健康对照与患者之间在性能上没有差异的时期与存在这种差异的时期交替出现。AD（H）D亚型以及令人惊讶的药物状态也不会影响此模式。所提出的发现可能反映了AD（H）D患者的多巴胺能系统的（阶段性）缺陷，而一线药物治疗并不能充分缓解该缺陷。提出的发现具有重要的临床和科学意义。健康对照与患者之间在性能上没有差异的时期与存在这种差异的时期交替出现。AD（H）D亚型以及令人惊讶的药物状态也不会影响此模式。所提出的发现可能反映了AD（H）D患者的多巴胺能系统的（阶段性）缺陷，而一线药物治疗并不能充分缓解该缺陷。提出的发现具有重要的临床和科学意义。健康对照与患者之间在性能上没有差异的时期与存在这种差异的时期交替出现。AD（H）D亚型以及令人惊讶的药物状态也不会影响此模式。所提出的发现可能反映了AD（H）D患者的多巴胺能系统的（阶段性）缺陷，而一线药物治疗并不能充分缓解该缺陷。提出的发现具有重要的临床和科学意义。