This dissertation aimed to investigate the utility of the ex-Gaussian approach to estimating intraindividual variability (IIV) of response times (RT) in diagnosing attention deficit/hyperactivity disorder (ADHD) in children ages 6 to 13 years old. Higher IIV is consistently noted in children with ADHD, but also with other disorders commonly associated with impairments in attention. Firstly, the relationship between IIV and attention abilities was investigated both in relation to parent ratings and participants’ objective performance. Secondly, IIVs utility as an objective measure for supplementing behavioural ratings in the diagnosis of ADHD, a diagnosis which is currently primarily assigned based on informant interviews and ratings of attention, was assessed. Participants included 46 children with ADHD and 58 children without ADHD. Children completed computerized tasks to estimate IIV and assess inattention and hyperactivity/impulsivity. Parents completed questionnaires aimed at assessing attention and hyperactive/impulsive behaviours of participants. Analyses revealed that IIV was predictive of parent ratings of inattention and hyperactivity/impulsivity as well as the number of omission errors made by participants. Regarding diagnostic utility, IIV significantly predicted group membership (ADHD vs Control). However, IIV did not improve diagnostic accuracy when parent ratings were used, such that parent ratings were superior at determining diagnosis. Overall, current results support the use of IIV, based on the ex-Gaussian approach, as an objective measure of attention problems such that it appears to be superior to omission errors on sustained attention CPT-type tasks. Additionally, while parent ratings of attention impairment remain the best predictor of ADHD diagnostic status, IIV may be helpful in determining when further assessment is required in the absence of those ratings. / Graduate / 2021-06-17

Made available in DSpace on 2015-05-14T12:36:51Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1355559 bytes, checksum: fe1c88470e43ce75f706ec9d15cc7bb1 (MD5) Previous issue date: 2014-07-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / With the advent of technological advances, increasingly demand solutions that use fewer resources, are faster and low cost. As a result, this paper proposed a hybrid approach using metaheuristics Greedy Randomized Adaptive Search Procedure (GRASP) and Iterated Local Search (ILS) applied to the Response Time Variability Problem (RTVP). Since this problem may involve allocation of scarce resources, such as industrial machinery or meeting rooms, going for scheduling of banking customers that require certain conditions, planning of TV ads or route taken by vehicles of logistic companies, etc. For application of the procedure, the movements of shifting symbols, swapping positions between symbols and one called double bridge, which is a mix of movements of shifting and swapping involving opposite symbols were used. The neighborhood structures were based on the movements described above, varying the number of symbols involved. Thus, the results obtained demonstrate that such procedures satisfied the problem and brought consistent results when compared with the literature. / Com o advento dos avanços tecnológicos, cada vez mais se procura soluções que utilizem menos recursos, sejam mais rápidos e de baixo custo. Em virtude disso, este trabalho propôs uma abordagem meta-heurística híbrida utilizando Greedy Randomized Adaptive Search Procedure (GRASP) e Iterated Local Search (ILS) aplicados ao Problema da Variabilidade do Tempo de Resposta. Este problema pode envolver desde alocação de recursos escassos, como por exemplo, máquinas industriais ou salas de reunião, passando pelo agendamento de clientes de um banco que requerem certas condições, o planejamento das propagandas de TV ou o percurso feito por caminhões de empresas transportadoras, dentre outros. Para a aplicação do procedimento, foram utilizados os movimentos de deslocamento do mesmo, permuta de posição entre símbolos e de um movimento chamado double brigde, que é uma mistura dos movimentos de deslocamento e permutação envolvendo símbolos opostos. As estruturas de vizinhança compostas basearam-se nos movimentos descritos anteriormente, variando a quantidade de símbolos envolvidos. Desta forma, os resultados obtidos demonstram que tais procedimentos trouxeram resultados satisfatórios ao problema e condizentes quando comparados com a literatura.