Building a Framework for a Dual Task Taxonomy

Abstract

The study of dual task interference has gained increasing attention in the literature for the past 35 years, with six MEDLINE citations in 1979 growing to 351 citations indexed in 2014 and a peak of 454 cited papers in 2013. Increasingly, researchers are examining dual task cost in individuals with pathology, including those with neurodegenerative diseases. While the influence of these papers has extended from the laboratory to the clinic, the field has evolved without clear definitions of commonly used terms and with extreme variations in experimental procedures. As a result, it is difficult to examine the interference literature as a single body of work. In this paper we present a new taxonomy for classifying cognitive-motor and motor-motor interference within the study of dual task behaviors that connects traditional concepts of learning and principles of motor control with current issues of multitasking analysis. As a first step in the process we provide an operational definition of dual task, distinguishing it from a complex single task. We present this new taxonomy, inclusive of both cognitive and motor modalities, as a working model; one that we hope will generate discussion and create a framework from which one can view previous studies and develop questions of interest.

Loss of gait control assessed by cognitive-motor dual-tasks: pros and cons in detecting people at risk of developing Alzheimer’s and Parkinson’s diseases

“…Prodromal markers represent Bsignatures^of an ongoing pathological process before the presence of typical symptoms allowing the clinical diagnosis (Heinzel et al 2016). The loss of gait control is commonly evaluated by dual-task walking paradigms, during which the subject performs a cognitive (attention-demanding) task while walking, to assess any modifications compared to the reference (i.e., single-task condition), in either the cognitive or the walking subtasks (Bdual-task cost^; Woollacott and Shumway-Cook 2002;McIsaac et al 2015). At the onset of mild cognitive impairment (MCI, which may in some cases represent the prodromal phase of AD), this method has been widely used to assess whether or not executive attention functions (i.e., refers to higher cognitive processes used to allocate attention among different tasks performed simultaneously) are abnormally impaired.…”

Retraining Automaticity: Recovering the Procedural Memory of Walking after Stroke

“…In a related consideration, patients with mild cognitive impairment (MCI) may have fewer cognitive resources to devote to the "equation" of dual task tolerance [21,22]. In contrast, redundancy or reserve in intelligence and cognition can afford enough shared resources to divide (simultaneous), or decide (allocate appropriate resources through filtering) when faced with dual task demands.…”

“…The timing of the rehearsal trials matters, for example, we know that spaced retrieval can lead to new skill development much quicker than other rehearsal schedules, even for people with cognitive impairment [25,26]. Another factor is whether the learner can use declarative memory to support the development of the new procedural learning [21]. If the learner needs to inhibit an existing procedural memory, in order to perform a new behavior that could also reduce the efficiency of learning.…”

“…Respectively, these versions superimpose serial subtraction and holding a cup of water, while conducting the timed walk test. Each test has inherent limitations in that the secondary tasks are not measured for accuracy or participation and, arguably (using McIsaac's definition [21]), may not truly be a secondary task, but rather just a more complex version of the TUG.…”

“…This must be carried out using reasonable expectations based on lesion size and location, age, learning style, and personality [59][60][61][62][63][64][65][66][67][68][69]. As McIsaac and colleagues [21] wrote, "In aging and disease states, declines in sensorimotor and cognitive functions may lead to reduced postural reserve and cognitive reserve creating overall greater demands for attention to the task. "…”