Heart Rate Changes Prior to Freezing of Gait Episodes Are Related to Anxiety

Freezing of gait (FOG) in Parkinson's disease (PD) has been shown to be more frequent in stressful situations, implicating anxiety. Heart rate (HR) has been shown to increase prior to a FOG episode supporting the notion that elevated stress levels may trigger FOG. However, no studies to date have investigated whether elevated HR precedes all subtypes of FOG or only those episodes that are driven by anxiety.

The present study sought to investigate whether 1) HR increases prior to FOG episodes in nonspecific environments (Experiment 1), and if 2) HR increases prior to FOG when provoked in high but not low threat environments using a virtual reality paradigm (Experiment 2).

In Experiment 1, 10 of 19 participants with PD and FOG (PD + FOG) experienced FOG during a series of walking trials. In Experiment 2, 12 of 23 participants with PD + FOG experienced FOG while walking across an elevated and ground level narrow plank in virtual reality. HR was collected throughout the duration of both experiments, while FOG was quantified by experts using video review and tagging.

HR significantly increased 2-3 seconds prior to a FOG episode during Experiment 1. In Experiment 2, HR significantly increased 4-6 seconds prior to a FOG episode, specifically while navigating the elevated plank. However, there were no significant increases in HR prior to FOG episodes when participants navigated the ground plank.

This study extends previous work further demonstrating that increases in HR prior to FOG episodes appear linked to elevated anxiety levels.