EEG signals may be affected by physiological and non-physiological artifacts hindering the analysis of brain activity. Blind source separation methods such as independent component analysis (ICA) are effective ways of improving signal quality by removing components representing non-brain activity. However, most ICA-based artifact removal strategies have limitations, such as individual differences in visual assessment of components. These limitations might be reduced by introducing automatic selection methods for ICA components. On the other hand, new fully automatic artifact removal methods are developed. One of such method is artifact subspace reconstruction (ASR). ASR is a component-based approach, which can be used automatically and with small calculation requirements. The ASR was originally designed to be run not instead of, but in addition to ICA. We compared two automatic signal quality correction approaches: the approach based only on ICA method and the approach where ASR was applied additionally to ICA and run before the ICA. The case study was based on the analysis of data collected from 10 subjects performing four popular experimental paradigms, including resting-state, visual stimulation and oddball task. Statistical analysis of the signal-to-noise ratio showed a significant difference, but not between ICA and ASR followed by ICA. The results show that both methods provided a signal of similar quality, but they were characterised by different usabilities.

Hemispheric Asymmetry Reduction in Old Adults (HAROLD) is one of the most well-known models of compensatory brain involvement in older adults. Most evidence supports its occurrence from the perspective of PET and fMRI studies, with a deficiency in electroencephalographic research in this domain. Therefore, we aimed to investigate the possibility of identifying the HAROLD pattern in older adults’ power of theta and alpha. The study sample comprised 50 older adults and 60 young adults performing n-back tasks while recording EEG signals. The level of cognitive performance and the theta and alpha power for pairs of symmetrical electrodes in the prefrontal, frontal, and parietal areas were analyzed. Older adults exhibited inferior cognitive performance compared to young adults and heightened theta power in the right hemisphere within the prefrontal and parietal areas. However, they also demonstrated increased alpha power in the right frontal pole, which contradicts the compensatory effects of theta power. Moreover, the two indicated phenomena of lateralization of theta and alpha power in older adults were unrelated to individual cognitive performance. The results make it challenging to discern whether the revealed age-related differences in theta and alpha power lateralization denote compensation, dedifferentiation, or nonselective recruitment as neutral features of brain activity in old adults.