The utility of intraindividual variability in selective attention tasks as an early marker for Alzheimer’s disease.

Abstract

This study explored differences in intraindividual variability in three attention tasks across a large sample of healthy older adults and individuals with very mild dementia of the Alzheimer's type (DAT). Three groups of participants (healthy young adults, healthy older adults, very mild DAT) were administered three computerized tasks of attentional selection and switching (Stroop, Simon, Task Switching). The results indicated that a measure of intraindividual variability, coefficient of variation (CoV; SD/Mean) increased across age and early-stage DAT. The CoV in Stroop discriminated the performance of ε4 carriers from noncarriers in healthy older controls and the CoV in Task Switching was correlated with CSF biomarkers predictive of DAT.

Associations between reaction time measures and white matter hyperintensities in very old age

“…One proposal holds that IIV is an early indicator of neurobiological disturbance (Hultsch, MacDonald, Hunter, Levy-Bencheton, & Strauss, 2000;Hultsch, Strauss, Hunter, & MacDonald, 2008). In support of this, greater variability is evident in individuals with agerelated disorders such as mild cognitive impairment and dementia (Christensen et al, 2005;Duchek et al, 2009;Gorus, De Raedt, Lambert, Lemper, & Mets, 2008;Hultsch et al, 2000;Strauss, Bielak, Bunce, Hunter, & Hultsch, 2007), Parkinson's disease (de Frias, Dixon, Fisher, & Camicioli, 2007) and also frontal lobe lesions (Stuss, Murphy, Binns, & Alexander, 2003).…”

“…One proposal holds that IIV is an early indicator of neurobiological disturbance (Hultsch, MacDonald, Hunter, Levy-Bencheton, & Strauss, 2000;Hultsch, Strauss, Hunter, & MacDonald, 2008). In support of this, greater variability is evident in individuals with agerelated disorders such as mild cognitive impairment and dementia (Christensen et al, 2005;Duchek et al, 2009;Gorus, De Raedt, Lambert, Lemper, & Mets, 2008;Hultsch et al, 2000;Strauss, Bielak, Bunce, Hunter, & Hultsch, 2007), Parkinson's disease (de Frias, Dixon, Fisher, & Camicioli, 2007) and also frontal lobe lesions (Stuss, Murphy, Binns, & Alexander, 2003).Given the suggestion that IIV is an indicator of neurobiological disturbance, a number of magnetic resonance imaging (MRI) studies have investigated the link between variability and structural brain measures. In healthy ageing, associations have been shown between IIV and white matter hyperintensities (WMH: Bunce et al, 2010;Bunce et al, 2007), white matter volume (Jackson, Balota, Duchek, & Head, 2012;Lovden et al, 2013;Ullen, Forsman, Blom, Karabanov, & Madison, 2008;Walhovd & Fjell, 2007) and diffusion tensor imaging metrics (e.g., FA -fractional anisotropy) (Deary et al, 2006;Fjell, Westlye, Amlien, & Walhovd, 2011;Mella, de Ribaupierre, Eagleson, & de Ribaupierre, 2013; Moy et al, 2011).…”

A Systematic Review of Longitudinal Associations Between Reaction Time Intraindividual Variability and Age-Related Cognitive Decline or Impairment, Dementia, and Mortality

“…For example, cross-sectional studies show that relative to healthy older persons, IIV is greater in individuals living with a range of neurodegenerative disorders including Parkinson's disease (e.g., de Frias, Dixon, Fisher, & Camicioli, 2007), MCI (e.g., Christensen et al, 2005;Dixon et al, 2007), and dementia (e.g., Gorus, De Raedt, Lambert, Lemper, & Mets, 2008;Hultsch et al, 2000), including early stage Alzheimer's disease (Duchek et al, 2009). However, given these findings of greater variability in the presence of age-related neuropathology, what evidence is there of associations between IIV and brain substrates?…”

Procesos de control ejecutivo en la enfermedad de Alzheimer.

“…Bondi et al (2002) confirman el efecto stroop con la puntuación de interferencia ajustada a la velocidad de procesamiento, y también encontraron que los pacientes cometen más errores de intrusión. Por su parte, Duchek et al (2009) aplican una tarea stroop a un grupo de adultos jóvenes, un grupo de mayores y un grupo de pacientes con EA muy inicial y toman las medidas están-dar de tiempo de reacción (TR) y de errores. También codifican la variabilidad individual ensayo a ensayo, para lo cual calculan el coeficiente de variación (CoV), que se computa dividiendo la desviación típica del sujeto por su media.…”