Dual-task motor performance with a tongue-operated assistive technology compared with hand operations.

BACKGROUND: To provide an alternative motor modality for control, navigation, and communication in individuals suffering from impairment or disability in hand functions, a Tongue Drive System (TDS) has been developed that allows for real time tracking of tongue motion in an unobtrusive, wireless, and wearable device that utilizes the magnetic field generated by a miniature disk shaped magnetic tracer attached to the tip of the tongue. The purpose of the study was to compare the influence of a concurrent motor or cognitive task on various aspects of simple movement control between hand and tongue using the TDS technology. METHODS: Thirteen young able-bodied adults performed rapid and slow goal-directed movements of hand and tongue (with TDS) with and without a concurrent motor (hand or tongue) or cognitive (arithmetic and memory) task. Changes in reaction time, completion time, speed, correctness, accuracy, variability of displacement, and variability of time due to the addition of a concurrent task were compared between hand and tongue. RESULTS: The influence of an additional concurrent task on motor performance was similar between the hand and tongue for slow movement in controlling their displacement. In rapid movement with a concurrent motor task, most aspects of motor performance were degraded in hand, while tongue speed during rapid continuous task was maintained. With a concurrent cognitive task, most aspects of motor performance were degraded in tongue, while hand accuracy during the rapid discrete task and hand speed during the rapid continuous task were maintained. CONCLUSION: Rapid goal-directed hand and tongue movements were more consistently susceptible to interference from concurrent motor and cognitive tasks, respectively, compared with the other movement.

Predictors of Financial Capacity in Young Adults.

OBJECTIVE: To examine several predictors of financial capacity as assessed via the Independent Living Scales Money Management (ILS-MM) subtest in a regression correlational design. METHOD: One hundred and five college students were administered measures of financial literacy and financial experience, as well as multiple neuropsychological measures assessing language, processing speed, executive functioning, and arithmetic. Using hierarchical regression analyses, we sought to predict performance on the two subscales of the ILS-MM-Problem Solving and Performance/Information. The former assesses financial knowledge (e.g., defining financial terms such as health insurance) whereas the latter assesses financial abilities (e.g., computing a financial balance). RESULTS: After controlling for demographic variables, financial literacy and experience predicted the Problem Solving subscale, but not the Performance subscale. Neuropsychological measures did not account for additional variance. In contrast, after controlling for demographic variables and financial literacy and financial experience, neuropsychological measures predicted the Performance but not the Problem Solving subscale. The key predictor was the Arithmetic subtest of the Wide Range Achievement Test4, which is not surprising given the mathematical demands of the task. Measures of executive functioning were not related to this measure. CONCLUSIONS: Financial capacity is a broad construct, encompassing many financial abilities and concepts. To predict these, a variety of measures is necessary: financial literacy and experience predict knowledge-based items, whereas neuropsychological measures, especially arithmetic, predict performance-based items. Clinical and research implications of these findings are discussed as well as directions for future investigation.

Corticomuscular coherence with and without additional task in the elderly.

Aging and dual-task paradigms often degrade fine motor performance, but the effects of aging on correlated neural activity between motor cortex and contracting muscle are unknown during dual tasks requiring fine motor performance. The purpose of this study was to compare corticomuscular coherence between young and elderly adults during the performance of a unilateral fine motor task and concurrent motor and cognitive tasks. Twenty-nine healthy young (18-38 yr) and elderly (61-75 yr) adults performed unilateral motor, bilateral motor, concurrent motor-cognitive, and cognitive tasks. Peak corticomuscular coherence between the electroencephalogram from the primary motor cortex and surface electromyogram from the first dorsal interosseous muscle was compared during steady abduction of the index finger with visual feedback. In the alpha-band (8-14 Hz), corticomuscular coherence was greater in elderly than young adults especially during the motor-cognitive task. The beta-band (15-32 Hz) corticomuscular coherence was higher in elderly than young adults across unilateral motor and dual tasks. In addition, beta-band corticomuscular coherence in the motor-cognitive task was negatively correlated with motor output error across young but not elderly adults. The results suggest that 1) corticomuscular coherence was increased in senior age with a greater influence of an additional cognitive task in the alpha-band and 2) individuals with greater beta-band corticomuscular coherence may exhibit more accurate motor output in young, but not elderly adults, during steady contraction with visual feedback.

Attenuation of corticomuscular coherence with additional motor or non-motor task.

OBJECTIVE: The study aimed to compare beta (15-30 Hz) band corticomuscular coherence between a unilateral hand motor task and concurrent motor or non-motor tasks. Additionally, we examined the potential associations between corticomuscular coherence and fine motor performance. METHODS: Ten healthy young right-handed adults performed unilateral, bilateral, concurrent motor-cognitive, and cognitive tasks. Electroencephalogram and electromyogram were recorded from the primary motor cortex and the first dorsal interosseous muscle, respectively, during steady contractions. RESULTS: Corticomuscular beta band coherence decreased (P<0.05) from the unilateral motor task with the right hand to the same extent in both the bilateral motor and motor-cognitive tasks. A decrease in corticomuscular coherence with concurrent tasks was also observed for the left hand (P<0.05). Beta band coherence was not associated with motor output steadiness or accuracy. CONCLUSIONS: Beta band coherence decreased during concurrent tasks irrespective of the additional task, most likely due to divided attention. There was no association between beta band coherence and fine motor performance during steady contractions. SIGNIFICANCE: This study supports that attention divided by an additional motor or non-motor task influences beta band corticomuscular coherence that was not associated with fine motor performance. The results suggest clinical relevance to identify what might occur in clinical distracter tasks.

A discriminative approach to EEG seizure detection.

Seizures are abnormal sudden discharges in the brain with signatures represented in electroencephalograms (EEG). The efficacy of the application of speech processing techniques to discriminate between seizure and non-seizure states in EEGs is reported. The approach accounts for the challenges of unbalanced datasets (seizure and non-seizure), while also showing a system capable of real-time seizure detection. The Minimum Classification Error (MCE) algorithm, which is a discriminative learning algorithm with wide-use in speech processing, is applied and compared with conventional classification techniques that have already been applied to the discrimination between seizure and non-seizure states in the literature. The system is evaluated on 22 pediatric patients multi-channel EEG recordings. Experimental results show that the application of speech processing techniques and MCE compare favorably with conventional classification techniques in terms of classification performance, while requiring less computational overhead. The results strongly suggests the possibility of deploying the designed system at the bedside.

Feature subset selection for age-related changes in EEG and EMG during motor tasks.

The paper presents an ongoing investigation into the feasibility of distinguishing between healthy young and older adults, but more specifically into the nature of the features that would provide this distinction. The present study compared the performance of forward, backward, and branch and bound feature selection algorithms when applied to electroencephalography and electromyography data. The results showed that the forward selection algorithm outperformed the other techniques for this particular problem. In addition, time domain features were primarily selected over frequency domain features. Validation of the selected subset suggests the approach is appropriate for future investigation.

Automated polysomnogram artifact compensation using the generalized singular value decomposition algorithm.

Manual/visual polysomnogram (psg) analysis is a standard and commonly implemented procedure utilized in the diagnosis and treatment of sleep related human pathologies. Current technological trends in psg analysis focus upon translating manual psg analysis into automated/computerized approaches. A necessary first step in establishing efficient automated human sleep analysis systems is the development of reliable pre-processing tools to discriminate between outlier/artifact instances and data of interest. This paper investigates the application of an automated approach, using the generalized singular value decomposition algorithm, to compensate for specific psg artifacts.

Effects of additional workload on hand and tongue performance.

Tongue Drive System (TDS) is an unobtrusive, wireless, and wearable device that allows for real time tracking of the tongue motion in the oral space for communication, control, and navigation applications. Utilizing the TDS, we were able to assess the use of tongue motion as a voluntary motor modality and its effect on the human performance in a realistic environment. Preliminary human trials were conducted on 13 able-bodied subjects to assess the speed and accuracy of rapid repetitive goal-directed movements during independent or concurrent use of hand (index finger) and the tongue. The accuracy of hand and tongue movements was decreased with the concurrent hand and tongue task compared with the independent movement task. The speed of hand movement was also decreased with the concurrent hand and tongue movements, but not with the concurrent hand and cognitive task (arithmetic and memory). In contrast, the speed of tongue movement was maintained with the concurrent hand and tongue movements. Instead, the tongue speed was decreased with the concurrent tongue and cognitive task. It was suggested that control via tongue movement with TDS would have the advantage of maintaining comparable speeds between independent and concurrent use over the hand movement control during the tasks that require rapid repetitive goal-directed movements.