Hyperphagia (extreme overeating) is the most significant factor contributing to obesity in Prader-Willi syndrome (PWS) and considered a cardinal feature. PWS is recognized as the most common syndromic cause of life-threating obesity, but no medications are currently available to decrease appetite or lessen obesity in PWS.
Preliminary studies have shown that a weak, non-invasive form of brain stimulation called transcranial direct current stimulation (tDCS) reduces food cravings and overeating in a small number of adults with PWS (N=5) in a combined study from Kansas University Medical Center and Harvard University. We will continue to investigate the use of tDCS using a 9 volt radio battery as a source of electrical current to control eating behaviors with 40 adults with PWS from the Prader-Willli Homes of Oconomowoc, WI (P-WHO) over the course of two years. During the first year, we measured the effects of tDCS with 20 adult participants with PWS by examining participants’ startle eyeblinks in response to sound while looking at a series of food and non-food pictures on a computer screen. This task has now been completed. Based on previous research eyeblink response in participants exposed to sound will vary while viewing positive, negative, or neutral pictures and can be used to assess food eating drive. During the second year, we will measure the effect of brain stimulation with 20 adult participants with PWS by examining brain wave activity and reactions (event-related brain potentials) to the same series of pictures, but without startle response. We will also be tracking the tDCS stimulation effects through eating questionnaires, behavioral and cognitive measures, weight and food intake during both years of study. This study will help determine if the use of tDCS brain stimulation would be an effective noninvasive inexpensive treatment to control food cravings and overeating in adults with PWS and impact favorably on brain activity measurable using event-related potentials (ERPs) in identifying differences before and after tDCS sessions.
Merlin Butler, PhD
University of Kansas Medical Center Research Institute