A framework for secondary cognitive and motor tasks in dual-task gait testing in people with mild cognitive impairment

Background: Cognition is a key factor in the regulation of normal walking and dual-task gait assessment is an accepted method to evaluate the relationship. The objective of this study was to create a framework for task complexity of concurrent motor and cognitive tasks with gait in people with mild cognitive impairment (MCI). Methods: Community-dwelling people with MCI (n = 41, mean age = 76.20 ± 7.65 years) and cognitively normal controls (n = 41, mean age = 72.10 ± 3.80 years) participated in this study. Gait velocity was collected using an instrumented walkway under one single task and six combined tasks of motor and cognitive activities. The cognitive cost was the difference between the single gait task and each of the concurrent motor and cognitive challenges. A repeated two-way measure ANOVA assessed the effect of cognitive group and walking test condition for each gait task test. Results: Gait velocity was significantly slower in the MCI group under all tasks. For both groups, the concurrent motor task of carrying a glass of water conferred a challenge not different from the cognitive task of counting backwards by ones. Performance of the complex cognitive task of serial seven subtractions reduced gait velocity in both groups, but produced a greater change in the MCI group (31.8%). Conclusions: Not all concurrent tasks challenge cognition-motor interaction equivalently. This study has created a framework of task difficulty which allows for the translation of dual-task test conditions to future research and clinical practice to ensure the accuracy of assessing patient deficits and risk

Children's construction task performance and spatial ability: controlling task complexity and predicting mathematics performance.

This paper presents a methodology to control construction task complexity and examined the relationships between construction performance and spatial and mathematical abilities in children. The study included three groups of children (N = 96); ages 7-8, 10-11, and 13-14 years. Each group constructed seven pre-specified objects. The study replicated and extended previous findings that indicated that the extent of component symmetry and variety, and the number of components for each object and available for selection, significantly predicted construction task difficulty. Results showed that this methodology is a valid and reliable technique for assessing and predicting construction play task difficulty. Furthermore, construction play performance predicted mathematical attainment independently of spatial ability

Comparisons of Animal “Smarts” Using the First Four Stages of the Model of Hierarchical Complexity

The Model of Hierarchical Complexity is a behavioral model of development and evolution of the complexity of behavior. It is based on task analysis. Tasks are ordered in terms of their hierarchical complexity, which is an ordinal scale that measures difficulty. The hierarchical difficulty of tasks is categorized as the order of hierarchical complexity. Successful performance on a task is called the behavioral stage. This model can be applied to non-human animals, and humans. Using data from some of the simplest animals and also somewhat more complex ones, this analysis describes the four lowest behavioral stages and illustrate them using the behaviors of a range of simple organisms. For example, Stage 1 tasks, and performance on them, are addressed with automatic unconditioned responses. Behavior at this Stage includes sensing, tropisms, habituation and, other automatic behaviors. Single cell organisms operate at this Stage. Stage 2 tasks include these earlier behaviors, but also include respondent conditioning but not operant conditioning. Animals such as some simple invertebrates have shown respondent conditioning, but not operant conditioning. Stage 3 tasks coordinate three instances of these earlier tasks to make possible operant conditioning. These stage 3 performances are similar to those of some invertebrates and also insects. Stage 4 tasks organisms coordinate 2 or more circular sensory-motor task actions into a superordinate “concept”. This explanation of the early stages of the Model of Hierarchical Complexity may help future research in animal behavior, and comparative psychology.

Identifying the task variables that predict object assembly difficulty.

We investigated the physical attributes of an object that influence the difficulty of its assembly. Identifying attributes that contribute to assembly difficulty will provide a method for predicting assembly complexity

Surrogate in-vehicle information systems and driver behaviour: Effects of visual and cognitive load in simulated rural driving

The underlying aim of HASTE, an EU FP5 project, is the development of a valid, cost-effective and reliable assessment protocol to evaluate the potential distraction of an in-vehicle information system on driving performance. As part of this development, the current study was performed to examine the systematic relationship between primary and secondary task complexity for a specific task modality in a particular driving environment. Two fundamentally distinct secondary tasks (or surrogate in-vehicle information systems, sIVIS) were developed: a visual search task, designed such that it only required visual processing/demand and an auditory continuous memory task, intended to cognitively load drivers without any visual stimulus. A high fidelity, fixed-base driving simulator was used to test 48 participants on a car following task. Virtual traffic scenarios varied in driving demand. Drivers compensated for both types of sIVIS by reducing their speed (this result was more prominent during interaction with the visual task). However, they seemed incapable of fully prioritising the primary driving task over either the visual or cognitive secondary tasks as an increase in sIVIS demand was associated with a reduction in driving performance: drivers showed reduced anticipation of braking requirements and shorter time-to-collision. These results are of potential interest to designers of in-vehicle systems

The acquisition of Sign Language: The impact of phonetic complexity on phonology

Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality

The task complexity and Extraversion: an ERP study

Trying to prove the validity of Eysenck’s theories for the biological basis of personality many data for the differences between extraverts and introverts were collected. It was obtained, that the ERP differences between extraverts and introverts depend on the intensity and frequency of stimulation, but the papers concerning task difficulty dependence are very limited. The purpose of this work was to investigate how the task complexity affects ERP differences between extraverts and introverts. For testing the extraversion we used Eysenck Personality Questionary (EPQ). We recorded EEG under four equal audio series of pseudo-randomized low and high tones. We changed the level of task complexity by different instructions: 1 - passive listening; 2 – answering with the right index finger to the low tone and the left index finger to the high tone; 3 – counting the low tones; 4 – answering with the right index finger to low tones; We averaged stimulus locked ERP across each series and tones for extraverts and introverts separately. It was evident that the ERP differences between extraverts and introverts depend on the task complexity. We found P2, N2 and P3 latency differences and N1, P2, N2 and P3 amplitude differences. As whole extraverts showed larger N2 amplitudes and shorter N2 latencies. The differences were more pronounced in the task supposed less complexity and decreased with the increase of task complexity

Everyday walking with Parkinson's disease: understanding personal challenges and strategies

PURPOSE: This qualitative study was designed to explore the personal experience of everyday walking with Parkinson's disease (PD), the challenges and the strategies employed to compensate for difficulties, to help contextualise the scientific knowledge base. METHODS: Semi-structured interviews were undertaken with a sample of 20 people with idiopathic PD (12 male, 8 female; mean age 65 years (range 50 - 80); mean disease duration 10 years (range 2.5 - 26). Verbatim interview transcripts were analyzed thematically using NUD*IST N6 qualitative data analysis software. RESULTS: Walking was invariably performed as an integral part of a purposeful activity within a specific context, termed walking 'plus', with challenges encountered by people with PD in three main areas: Undertaking tasks; negotiating environments; and making transitions to walking. The two key strategies to compensate for difficulties experienced were monitoring through the use of concentration, and correcting through generating rhythm and size of steps. Carers supported monitoring and correcting. CONCLUSION: People with PD need to constantly assess and drive their walking performance. Attentional resources, which can themselves be compromised in PD, were used to accomplish what is normally a largely automatic activity. Personal accounts support scientific hypotheses. Rehabilitation interventions and measurements in PD need to reflect both the physical and psychosocial context of everyday walking

Identifying the task characteristics that predict children's construction task performance

Construction tasks form a major part of children’s play and can be linked to achievement in maths and science. However there is a lack of understanding of construction task ability and development. Therefore, there is little foundation for the applied use of construction tasks, such as in teaching or research, as there are no apparent methods for assessing difficulty. This empirical research identifies four construction task characteristics that impact on cognition and predict construction task difficulty in children aged 7-8 and 10-11 years and adults. The results also reveal a developmental trajectory in construction ability. The research provides a method to quantify, predict and control the complexity of construction tasks for future research and to inform applied use

Attention, effort, and fatigue: Neuropsychological perspectives

Models of attention, effort, and fatigue are reviewed. Methods are discussed for measuring these phenomena from a neuropsychological and psychophysiological perspective. The following methodologies are included: (1) the autonomic measurement of cognitive effort and quality of encoding; (2) serial assessment approaches to neurophysiological assessment; and (3) the assessment of subjective reports of fatigue using multidimensional ratings and their relationship to neurobehavioral measures