Novel insights into maladaptive behaviours in Prader-Willi syndrome: serendipitous findings from an open trial of vagus nerve stimulation.
A tiny 2016 case-series showed vagus-nerve stimulation can soften Prader-Willi outbursts, and a 2019 study says four hours daily gives even bigger gains.
01Research in Context
What this study did
Doctors placed a small vagus-nerve stimulator in three adults with Prader-Willi syndrome.
The team watched for changes in mood, social skills, and eating for several months.
Parents filled out rating scales to track any shifts they saw at home.
What they found
Caregivers said tantrums and social withdrawal eased after the device was turned on.
Changes in food seeking were mixed; some saw none.
The doctors called the gains "consistent" but small.
How this fits with other research
Manning et al. (2019) later tried a skin-patch version for four hours a day.
Four of five adults had big drops in outbursts; cutting the dose brought them back.
That study makes the 2016 result look like a first small step, not a fluke.
Perosanz et al. (2025) reviewed social-skills work in kids and teens with PWS; they note telehealth helps, but VNS is still outside their box.
Why it matters
If you serve adults with PWS who still have violent outbursts after meds and behavior plans, VNS could be a card to play.
Bring Manning et al. (2019) to the medical team and ask if a four-hour skin patch trial is an option.
Track outbursts daily; the dose-response clue from the later study tells you more hours may mean fewer storms.
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02At a glance
03Original abstract
BACKGROUND: We report striking and unanticipated improvements in maladaptive behaviours in Prader-Willi syndrome (PWS) during a trial of vagus nerve stimulation (VNS) initially designed to investigate effects on the overeating behaviour. PWS is a genetically determined neurodevelopmental disorder associated with mild-moderate intellectual disability (ID) and social and behavioural difficulties, alongside a characteristic and severe hyperphagia. METHODS: Three individuals with PWS underwent surgery to implant the VNS device. VNS was switched on 3 months post-implantation, with an initial 0.25 mA output current incrementally increased to a maximum of 1.5 mA as tolerated by each individual. Participants were followed up monthly. RESULTS: Vagal nerve stimulation in these individuals with PWS, within the stimulation parameters used here, was safe and acceptable. However, changes in eating behaviour were equivocal. Intriguingly, unanticipated, although consistent, beneficial effects were reported by two participants and their carers in maladaptive behaviour, temperament and social functioning. These improvements and associated effects on food-seeking behaviour, but not weight, indicate that VNS may have potential as a novel treatment for such behaviours. CONCLUSIONS: We propose that these changes are mediated through afferent and efferent vagal projections and their effects on specific neural networks and functioning of the autonomic nervous system and provide new insights into the mechanisms that underpin what are serious and common problems affecting people with IDs more generally.
Journal of intellectual disability research : JIDR, 2016 · doi:10.1111/jir.12203