Exploration of the differences in effort regulation among ADHD subtypes - based on ex-gaussian distribution

• Main Authors: Hwang, Shoou Lian, 黃守廉
• Other Authors: Hsu, Wen Yau
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/72398742338831246869

博士 === 國立政治大學 === 心理學研究所 === 99 === Background: Literature documents that the reaction time (RT) assessed by a variety of neuropsychological tasks is typically both slower and more variable in individuals with attention-deficit hyperactivity disorder (ADHD) than the controls. Some studies further lent evidence to support a relationship between the RT patterns and the difficulty of effort regulation in ADHD. Objectives: 1) To explore the moderating effects from effort regulation (the inter-stimulus intervals (ISI) and Block) on three parameters (μ, σ, τ) of ex-Gaussian distribution of the reaction time of the Conner’s Continuous Performance Test (CCPT) among individuals with ADHD as compared with the controls; 2) To examine the association between the ex-Gaussian parameters and ADHD symptoms and the response errors in the CCPT to infer the psychological meanings of ex-Gaussian parameters (μ, σ, and τ); 3) To understand effort regulation for the ADHD-Combined Type (ADHD-C) and ADHD-Inattentive Type (ADHD-IA) by examining the relationship between effort regulation process (ISI and Block effects) and ex-Gaussian parameters (μ, σ, and τ); 4) To compare the performance in the time reproduction dual tasks and its relationship with ex-Gaussian parameters (μ, σ, and τ) among the ADHD-C, ADHD-IA, and controls; 5) To examine the developmental change of ex-Gaussian parameters (μ, σ, and τ) and to test the difference among the two age groups (adolescent vs. child) with three diagnostic groups (ADHD-C, ADHD-IA, and controls) on ex-Gaussian parameters. Methods: We assessed 261 participants with DSM-IV ADHD-C (221 Boys, 84.7%), 151 participants with ADHD-IA (128 Boys, 84.8%), and 161 typically developing controls (124 Boys, 77.0%). Their age ranged from 6 to 16 years old. All the participants and their parents were interviewed with the Chinese version of the Kiddie Epidemiologic Version of the Schedule for Affective Disorders and Schizophrenia to confirm the psychiatric diagnosis of ADHD and other psychiatric disorders. Participants also received the Chinese versions of the Conners’ Parent Rating Scale-revised: Short Form (CPRS-R: S), the Conners’ Teacher Rating Scale-revised: Short Form (CTRS-R: S), the Swanson, Nolan, and Pelham, version IV scale (SNAP-IV)-Parent/Teacher Forms, the Time Perception Single and Dual Tasks, the CCPT and Intelligence (WISC-Ⅲ). Results: Participants with ADHD had a smaller μ and larger σ and τ with the largest effect sizes from τ. As ISI/Block increased, the magnitude of greater τ in participants with ADHD than controls increased. As the ISI increased, μ became slower in both groups; as the Block increased, μ became smaller only noted in participants with ADHD. There were significant group differences (ADHD/control) in σ estimation across different ISIs rather than in different Block levels. Regarding the association between ADHD symptoms and ex-Gaussian parameters (μ, σ, and τ), only τ was related to ADHD symptoms. Moreover, μ was correlated with commission errors of the CCPT; τ was correlated with omission errors of the CCPT. ADHD subtypes analysis revealed that participants with ADHD-C had smaller μ than participants with ADHD-IA without significant difference in τ; there was no subtype difference in time reproduction but the differences between the ADHD and control groups were magnified with increased time intervals and task complexity. Moreover, the variance of the time reproduction performance can be explained well by τ. As to the developmental comparison (children vs. adolescents), larger τ in participants with ADHD than control participants did not vary between child and adolescent participants. On the other hand, there were development changes in μ and σ estimates. For example, adolescents with ADHD had smaller μ than the controls without group difference in σ. Discussion: This study contributes not only to our understanding about RT in ADHD, but also to provide evidence to support the Cognitive-Energetic Model for ADHD. The findings also demonstrated similar compensation in effort regulation between the ADHD-C and ADHD-IA. Moreover, the findings support the cross-validity between time perception and effort regulation. Among the three ex-Gaussian parameters, τ is the most significant index to differentiate ADHD from non-ADHD. Finally, this study provides strong evidence to support the ex-Gaussian parameter as an appropriate method to assess the energetic pool of the Cognitive-Energetic Model for ADHD. A theoretical model for intervention can be established by taking the pathological model of Cognitive-Energetic Model for ADHD as reference.