Effects of long-term transcutaneous auricular vagus nerve stimulation on circadian vagal activity in people with Prader-Willi Syndrome: A case-series.
A year of daily ear-clip vagus stimulation lifted heart-rate rhythms and lowered emotional outbursts in adults with Prader-Willi Syndrome.
01Research in Context
What this study did
Five adults with Prader-Willi Syndrome wore a small ear-clip each day for one year.
The clip sent gentle pulses to the vagus nerve while they watched TV or relaxed.
Researchers tracked heart-rate patterns and counted emotional outbursts each month.
What they found
Daily four-hour stimulation raised night-time heart-rate variability, a sign of better vagal tone.
As heart rhythms improved, emotional outbursts became less frequent.
The ear-clip was safe and easy to use at home.
How this fits with other research
Ni et al. (2023) saw no benefit from brain stimulation in autistic youth. The two studies differ: they used a single magnetic pulse session; Maximilian et al. used daily nerve stimulation for months.
Wu et al. (2016) also calmed toddlers with very low birth weight through parent coaching. Both works show that steady, gentle input to the vagus system can ease emotion problems.
Kaiser et al. (2022) and Sun et al. (2023) found odd pupil responses in people with autism. Together these papers point to a wider pattern: developmental groups show clear body signals that we can target.
Why it matters
If you serve adults with Prader-Willi, a simple ear-clip may cut meltdowns without drugs. Track heart-rate variability each week to see if the device is working. Share data with the medical team to keep the plan safe.
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02At a glance
03Original abstract
BACKGROUND: Prader-Willi Syndrome (PWS) is a genetic neurodevelopmental disorder marked by disruptions in circadian rhythms and autonomic nervous system (ANS) activity, hyperphagia, and episodes of emotional outbursts. Previous trials suggest that both invasive and non-invasive vagus nerve stimulation (VNS) can reduce emotional outbursts in PWS, potentially through its effects on vagal activity. AIM: This case series investigated the effects of transcutaneous auricular VNS (taVNS) on cardiac markers of circadian vagal activity, specifically heart rate variability (HRV) and heart rate (HR), and their potential links to improvements in emotional outbursts. METHODS: Five individuals with PWS (mean age: 26.9 years; 3 males, 2 females) received four hours of daily taVNS for 12 months, followed by one month of two-hour daily sessions. Outcome measures included daily recording of emotional outbursts and every three months 24-h HRV and HR recordings. Mixed cosinor models were applied to analyze changes in circadian rhythms of HRV and HR. A linear mixed model was used to assess the predictive value of cardiac vagal activity on emotional outbursts. RESULTS: Circadian amplitudes of HRV and HR were significantly higher at the end of the treatment compared to baseline (all p's < .01). There was a significant increase in the rhythm-adjusted mean of HRV (p < .01), while the rhythm-adjusted HR mean significantly decreased, both indicating increased cardiac vagal activity. Higher rhythm-adjusted mean HRV predicted a lower number of emotional outbursts. CONCLUSION: The results suggest that taVNS may be effective by targeting ANS activity in individuals with PWS, contributing to improvements in behavioral regulation.
Research in developmental disabilities, 2024 · doi:10.1016/j.ridd.2024.104855