Clinical Trial: Pilot Study of Startle-response Test to Assess Transcranial Direct Current Stimulation-induced Modulation of Hyperphagia in Prader-Willi Syndrome
Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Interventional
Official Title: Pilot Study of Startle-response Test to Assess Transcranial Direct Current Stimulation- Induced Modulation of Hyperphagia in Prader-Willi Syndrome
Brief Summary: The purpose of this study is to determine the effects of transcranial direct current stimulation (tDCS) as it modifies hyperphagia in obese subjects, non-obese subjects, and subjects with Prader-Willi syndrome (PWS).
Detailed Summary:
PWS is characterized by hypotonia, feeding difficulties, developmental delay and failure to thrive during infancy, and by an insatiable appetite (hyperphagia), rapid weight gain and obesity in early childhood.
Hyperphagia is one of the most prominent and debilitating features of PWS, and currently no pharmaceutical drug has been successful in decreasing appetite in such patients.
tDCS is a safe, noninvasive method whereby a weak electric current is directly transmitted into the brain via external electrodes connected to a 9-volt radio battery. It is based on decades-old observations that nerve cell firing can be altered by low amplitude direct current (DC). The researchers in this study believe that tDCS may have a positive impact on hyperphagia and weight.
In this study, the investigators intend to assess whether the effects tDCS differ between obese subjects, non-obese subjects, and subjects with Prader-Willi syndrome by measuring the amplitude and latency of eyeblink startle responses to a set of food- and non-food-related visual stimuli in all subjects, various hyperphagia questionnaires, and cognitive and behavioral assessments. It is hypothesized that as a group, subjects with Prader-Willi syndrome will demonstrate behavioral and psychometric evidence of abnormal food image processing, craving and associated behaviors relative to our control groups, and this group may receive potentially beneficial effects from tDCS sessions. Obese subjects are also predicted to have decreased hyperphagia and food cravings as a result of tDCS.
Sponsor: University of Kansas Medical Center
Current Primary Outcome: Amplitude of eyeblink startle responses [ Time Frame: Change from Baseline to Week 6 ]
Comparing the amplitude of eyeblink startle responses to a set of food- and non-food-related visual stimuli in all subjects to measure effect of tDCS.
Muscle contractions generated by the orbicularis oculi will be recorded by a BIOPAC systems bioamplifier (model EMG 100c) passing 10-500 Hz signals, sampling at a rate of 2000/second and amplified by a factor of 5000. Eyeblink startle-responses will be measured at two lead-intervals (2500 ms and 6000 ms) to assess emotional responses (e.g., early and late, respectively) for each picture stimulus. Startle responses will be assessed during (e.g., while viewing the food, puppy, etc.) and between (e.g., during washout periods; no-images) visual image-processing.
Original Primary Outcome: Same as current
Current Secondary Outcome: Latency of eyeblink startle responses [ Time Frame: Change from Baseline to Week 6 ]
Comparing the latency of eyeblink startle responses to a set of food- and non-food-related visual stimuli in all subjects to measure effect of tDCS.
Muscle contractions generated by the orbicularis oculi will be recorded by a BIOPAC systems bioamplifier (model EMG 100c) passing 10-500 Hz signals, sampling at a rate of 2000/second and amplified by a factor of 5000. Eyeblink startle-responses will be measured at two lead-intervals (2500 ms and 6000 ms) to assess emotional responses (e.g., early and late, respectively) for each picture stimulus. Startle responses will be assessed during (e.g., while viewing the food, puppy, etc.) and between (e.g., during washout periods; no-images) visual image-processing.
Original Secondary Outcome: Same as current
Information By: University of Kansas Medical Center
Dates:
Date Received: April 30, 2013
Date Started: April 2013
Date Completion: July 2017
Last Updated: September 22, 2016
Last Verified: September 2016
