Effects of transcutaneous vagus nerve stimulation in individuals aged 55 years or above: potential benefits of daily stimulation

Abstract

Ageing is associated with attenuated autonomic function. Transcutaneous vagal nerve stimulation (tVNS) improved autonomic function in healthy young participants. We therefore investigated the effects of a single session of tVNS (studies 1 and 2) and tVNS administered daily for two weeks (study 3) in volunteers aged ≥ 55 years. tVNS was performed using modified surface electrodes on the tragus and connected to a transcutaneous electrical nerve stimulation (TENS) machine. Study 1: participants (n=14) received a single session of tVNS and sham. Study 2: all participants (n=51) underwent a single session of tVNS. Study 3: participants (n=29) received daily tVNS for two weeks. Heart rate variability and baroreflex sensitivity were derived. Quality of life (QoL), mood and sleep were assessed in study 3. tVNS promoted increases in measures of vagal tone and was associated with greater increases in baroreflex sensitivity than sham. Two weeks of daily tVNS improved measures of autonomic function, and some aspects of QoL, mood and sleep. Importantly, findings showed that improvements in measures of autonomic balance were more pronounced in participants with greater baseline sympathetic prevalence. This suggests it may be possible to identify individuals who are likely to encounter significant benefits from tVNS.

Stress and Tinnitus; Transcutaneous Auricular Vagal Nerve Stimulation Attenuates Tinnitus-Triggered Stress Reaction

“…This indicates that taVNS is more efficient in older patients, a result that could be explained by lower starting levels of HRV in this group due to age-related decline in parasympathetic activity. The magnitude of taVNS-induced changes has been shown to be higher in individuals with lower starting HRV level (Bretherton et al, 2019). The taVNS significantly increased all HRV parameters: the mean R-R interval in 81%, Flexibility in 63%, Dynamics (RMSSD) in 69%, Tone in 68% of patients, and decreased the HRV age by 9 years.…”

“…Because HRV is a biomonitor for ANS function, we also analyzed HRV changes before and immediately after acute test-taVNS. HRV as well as HR have been found to be useful in monitoring the effects of taVNS (Clancy et al, 2014;Antonino et al, 2017;De Couck et al, 2017;Ylikoski et al, 2017;Badran et al, 2018b;Bretherton et al, 2019). Clancy et al (2014) demonstrated that 15 min of taVNS administered to the tragus significantly increased HRV, at least partly through reduction of sympathetic nerve activity.…”

“…Clancy et al (2014) demonstrated that 15 min of taVNS administered to the tragus significantly increased HRV, at least partly through reduction of sympathetic nerve activity. In addition, the acute taVNS has been demonstrated to improve spontaneous baroreflex sensitivity (BRS) that may be the most sensitive measure of ANS function and thereby the parasympathetic activity (Antonino et al, 2017;Bretherton et al, 2019). Normal aging is associated with increase in sympathetic prevalence and/or decreases in the vagal tone and overall variability, which is reflected in HRV (Stein et al, 1997;Kuo et al, 1999).…”

The rise of bioelectric medicine sparks interest among researchers, patients, and industry

“…Researchers are also investigating the potential health benefits of stimulating the vagus nerve through the outer ear (19). One study published in July found the self-administered stimulation boosted the quality of life, mood, and sleep compared with a sham treatment in older adults (20).…”

EEG alpha activity increased in response to transcutaneous electrical nervous stimulation in young healthy subjects but not in the healthy elderly

“…Most of the studies which evaluated the clinical efficacy of TENS were on young subjects. There was a limited number of studies, which have investigated the effect of aging on TENS application (Grant et al, 1999;Cheing, Hui-Chan & Chan, 2002;Ng, Leung & Poon, 2003;Bergeron-Vézina et al, 2015;Daguet et al, 2018;Bretherton et al, 2019). Bergeron-Vézina et al (2015) reported TENS as an effective nonpharmacological treatment option in young, but not in elderly subjects.…”