Objective: To examine the use of EEG during the performance of two well-known paradigms, dual task and oddball, to reveal changes in brain activation during walking.

Background: Walking in everyday life requires coping with challenging conditions such as dual tasking, and thus considered to be controlled by higher cognitive processes. The effects of dual-task on behavior and their association with fall risk in older adults and patients with Parkinson’s disease (PD) have been vastly investigated. In recent years, more direct evidence related to changes in brain activation during dual task are starting to emerge. Electroencephalogram (EEG) is a neuroimaging method that can be useful in investigating brain activity during real dual task walking (1).

Methods: 13 young adults (age: 32.2±1.6yrs; 54% men), 10 older adults (age: 67.1±1.7yrs; 40% men), and 10 patients with PD (age: 61.8±3.7yrs; 60% men; UPDRS motor: 22.8±0.8) performed an audio oddball task during standing and walking on a treadmill while wearing a wireless 20 channel EEG cap. The oddball task, is highly used in neuropsychological studies to elicit an automatic neural response (P300) considered an event related potential (ERP) associated with attention (2). This task was performed during walking and standing. Amplitude and latency of the P300 were compared between and within groups using liner mix model analysis.

Results: Differences in P300 latency were observed between standing and walking (p=0.014), between groups (p<0.001), with a task x group interaction (p=0.036). During standing older adults (p=0.020) and patients with PD (p<0.001) showed delayed P300 compared to young adults. Moreover, during walking P300 latency gradually increased with age and disease, with older adults presenting longer P300 latency than young adults (p=0.001) and patients with PD showing longer P300 latency than older adults (p<0.001). No significant changes in P300 amplitude were found between tasks or between groups.

Conclusions: These findings provide direct evidence that walking relays on higher cognitive processes associated with attention. P300 latency reflects the stimulus classification speed, which is an index of stimulus processing rather than response generation. Therefore, our findings may indicate that changes in gait and the higher fall risk in aging and neurodegeneration may be a result of impairments in speed and stimulus processing.

References: (1) Malcolm BR, Foxe JJ, Butler JS, Mowrey WB, Molholm S, De SP. Long-term test-retest reliability of event-related potential (ERP) recordings during treadmill walking using the mobile brain/body imaging MoBI) approach. Brain Res 2017. (2) Huang WJ, Chen WW, Zhang X. The neurophysiology of P 300–an integrated review. Eur Rev Med Pharmacol Sci 2015;19:1480-1488.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/new-approach-to-assess-changes-in-brain-activation-during-real-walking-using-eeg/