In this study, we analyzed the influence of artificially imposed attention variations using the auditory oddball paradigm on the cortical activity associated to motor preparation/execution. EEG signals from Cz and its surrounding channels were recorded during three sets of ankle dorsiflexion movements. Each set was interspersed with either a complex or a simple auditory oddball task for healthy participants and a complex auditory oddball task for stroke patients. The amplitude of the movement-related cortical potentials (MRCPs) decreased with the complex oddball paradigm, while MRCP variability increased. Both oddball paradigms increased the detection latency significantly (p<0.05) and the complex paradigm decreased the true positive rate (TPR) (p=0.04). In patients, the negativity of the MRCP decreased while pre-phase variability increased, and the detection latency and accuracy deteriorated with attention diversion. Attention diversion has a significant influence on MRCP features and detection parameters, although these changes were counteracted by the application of the laplacian method. Brain-computer interfaces for neuromodulation that use the MRCP as the control signal are robust to changes in attention. However, attention must be monitored since it plays a key role in plasticity induction. Here we demonstrate that this can be achieved using the single channel Cz.

Background: In older age, walking ability gradually decreases due to factors including impaired balance, reduced muscle strength, and impaired vision and proprioception. Further, cognitive functions play a key role during walking and gradually decline with age. There is greater variability in gait parameters when the demands during walking increase, in dual- and multiple-task situations. The aim of this study was to analyze gait parameters while performing a demanding cognitive and motor dual task in three different age-related healthy elderly subject groups. Method: A total of 132 healthy individuals (54 males, 78 females) were divided into three groups—55 to 65, 66 to 75, and 76 to 85 years. The subjects performed a basic walking task, dual motor task, dual mental task, and combined motor and mental task while walking. The gait parameters cycle time, stride length, swing time, and double support time were noted, as well as the variability of those parameters. Results: Cycle time was longer and stride length was shorter in the >76-year-old group than in the 51–65-year-old group in all test conditions. A comparison of all three groups did not show a significant difference in swing time, while double support time was increased in the same group. Conclusions: Changes are observed when gait is performed simultaneously with an additional motor or cognitive task. Early detection of gait disorders can help identify elderly people at increased risk of falls. Employing a dual-task paradigm during gait assessment in healthy elderly subjects may help identify cognitive impairment early in the course of the disturbance.

Purpose: Huntington’s disease (HD) is an neurodegenerative genetic disorder with characteristic gait changes. HD also results in a range of cognitive impairments, such as difficulties to divide attention, or simultaneously monitoring two tasks. Aim: The impact of cognitive and/or motor tasks on HD gait has not been fully elucidated. The aim of this study was to examine gait in HD patients while performing motor and/or cognitive dual tasks walking. Methods: Gait performance was measured with and without performing concurrent cognitive and/or motor tasks. Sixteen HD patients and 24 healthy control subjects performed a self-paced basic walking task, a dual motor, a dual mental and a combined motor and mental task while walking. Results: Base walk gait parameters are significantly different between HD and HC groups. Same is true for motor, mental and combined tasks comparisons of HD and HC subjects. Gait velocity is also significantly reduced in HD compared to HC for all experimental conditions. Comparison of base walk and mental task performance showing differences in CT, SL, DST and CV SL, while base walk to motor task comparison is different only in SL. No differences were found when motor and combined tasks were compared to mental task in HD patients. Conclusion: Gait pattern in HD patients while performing motor and/or cognitive dual tasks walking is remarkable preserved. Gait parameters are changed in order to reduce possible falls, and lack of differences of dual tasks gait parameters variability is attributed that patients minimizing risk of falling and preserving stability.