Fear-related visual stimuli do not promote internal focus of attention in older adults

Abstract

Background: The influence of internal focus (IF) on postural balance needs to be determined when assessing fall risk in older adults. Moreover, the mechanism through which IF is triggered should be elucidated.

Research question: Does fear unrelated to threats to postural balance modulate IF during postural control?

Methods: The participants were 16 community-dwelling older adults. We generated visual stimuli for neutral and fear conditions using the International Affective Picture System. Participants were assessed for postural control while standing on a stabilometer and looking at projected images. The IF allocated to postural control during task was assessed immediately after the task using the Conscious Movement Processing subscale of the Movement-Specific Reinvestment Scale (MSRS-CMP). Sympathetic activity was assessed using the mean low-frequency/high-frequency ratio (LF/HF), and posture was evaluated using the root mean square area (RMS-A), anteroposterior mean power frequency (MPF-AP), mediolateral MPF, and co-contraction index. Differences (Δ) in the MSRS-CMP, RMS-A and MPF between the neutral/fear conditions and control condition were calculated. Each index was also compared among the control, neutral, and fear conditions. The correlations between ΔMSRS-CMP and postural measures were evaluated. Equivalence tests were conducted to determine whether change of IF was different among conditions.

Results: The MSRS-CMP score did not differ significantly among conditions; equivalence was observed. The LF/HF and MPF-AP in the fear condition were higher than in the other conditions. The RMS-A in the fear condition was lower than in the neutral condition. ΔMSRS-CMP and ΔMPF-AP were significantly negatively correlated.

Significance: The results of this study suggest that feelings of fear affect postural control but not the IF of attention. Taken together with previous research, the findings of this study suggest that consideration of the fear-inducing context may be useful in assessments of, and interventions for, older adults with a fall risk.

Keywords: Fear; Internal focus; Older adults; Postural control.