Age-dependent changes in steady-state visual evoked potentials

Variability in user performance has been a crucial hurdle that prevents the adoption of brain-computer interfaces (BCIs), but the factors that led to the variations were unclear. This study investigates the effect of age on the strength of steady-state visual evoked potentials (SSVEPs) – an important attribute that determines the BCI performance. Ninety-three subjects ranging from six to 78 years old were recruited for the study, and each of them was tested for their SSVEPs in response to flickering lights of five different frequencies presented at random sequences. The results showed that there is a significant correlation between the strength of SSVEP and user age, with weaker SSVEP response registered in older subjects at all stimulation frequencies tested. Further inter-group comparisons indicated that older subjects tended to show more attenuated SSVEP response compared to the younger and the middle-aged subjects, while there is no significant difference in the SSVEP amplitude between the subjects from the younger and the middle-age groups. The SSVEP response was stronger when elicited using light-emitting diode (LED) compared to liquid crystal display (LCD) stimulators. These findings suggest that age as an important factor in BCI performance, and learning about the age-associated changes could provide additional insight into adapting the BCI system to individual users.