Using Functional Near-Infrared Spectroscopy to Identify Biomarkers of Skin Picking Behavior in PWS

Funding Summary

In previous research, Dr. Hall has found that altered internal bodily cues (interoceptive processes), such as pain, itch, and sensual touch, may be involved in skin picking behavior in PWS. Here, he will employ a sophisticated brain imaging method called functional near-infrared spectroscopy (fNIRS), which allows brain activity to be measured under more naturalistic settings, to examine which regions of the brain are activated before, during, and after the occurrence of skin picking behavior.

Lay Abstract

Skin picking is one of the most perplexing and distressing behaviors commonly exhibited by people with Prader-Willi syndrome (PWS). These behaviors can result in bleeding, sores, scars, disfigurement, and other medical problems if left untreated and cause significant distress and anxiety for the individual and their families. Unfortunately, very little is known about why skin picking occurs in PWS and the underlying mechanisms that may be involved. Consequently, treatments specifically tailored for people with PWS have not been forthcoming. In a previous study, we took pictures of the brain while participants with PWS were engaged in skin picking in a scanner and found that dysregulation of internal bodily cues called interoceptive processes, such as pain, itch, and sensual touch, may be involved in skin picking behavior in PWS. However, given the artificial nature of the scanning environment, it is unclear whether these findings apply to real world environments and scenarios. Furthermore, it is unknown whether skin picking in PWS is similar or different to the skin picking observed in people with Skin Picking Disorder, a neuropsychiatric condition that affects approximately 1% to 5% of the general population.  Therefore, to further inform and expand our understanding of skin picking behavior in PWS, in the present study, we will employ a newer sophisticated brain imaging method called functional near-infrared spectroscopy (fNIRS) that allows brain activity to be measured under more naturalistic conditions and settings. In our new study, we will recruit a group of participants with PWS who show skin picking behavior on a daily basis and a group of participants diagnosed with Skin Picking Disorder (but who do not have PWS) and invite them to come to Stanford with their primary caregiver for a 2-day assessment of skin picking behavior. Specifically, we will use fNIRS to examine which regions of the brain are activated before, during after occurrences of skin picking behavior in each group and compare brain activation patterns in the two groups. This research is important because identifying the specific mechanisms underlying skin picking behavior in PWS will help us to target behavioral and pharmacological treatments more efficiently and effectively for people with PWS in the future. For example, if interoceptive dysfunction is reliably found to be associated with skin picking behavior in PWS, this will support adoption of interventions designed to increase interoceptive awareness, such as teaching the person to understand and respond more appropriately to internal body cues. Further, given that fNIRS is a relatively inexpensive and portable method for measuring biomarkers of behaviors common to people with PWS, this study will allow us to determine whether fNIRS could be be utilized as a reliable, valid, and sensitive outcome measure for evaluating pharmacological and/or behavioral interventions in future clinical trials for people with PWS.