Optimizing the Social Engagement System in Prader-Willi Syndrome: Insights From the Polyvagal Theory

The Polyvagal Theory focuses on how function and structure changed in the vertebrate autonomic nervous system during evolution. The theory is named for the vagus, a major cranial nerve that regulates bodily state. As a function of evolution, humans and other mammals have a "new" vagal pathway that links the regulation of bodily state to the control of the muscles of the face and head including the middle ear muscles. These pathways regulating body state, facial gesture, listening (i.e., middle ear muscles), and vocal communication collectively function as a Social Engagement System (SES). Because the Social Engagement System is an integrated system, interventions influencing one component of this system (e.g., middle ear muscles) may impact on the other components. Individuals with Prader-Willi Syndrome (PWS) exhibit many behaviors that are consistent with a compromised Social Engagement System. Atypical function of the Social Engagement System results in problems associated with state regulation (e.g., impulsivity, tantrums, and difficulty with change in routine), ingestion (e.g., difficulties in sucking at birth, hyperphagia), coordination of suck/swallow/breathe, intonation of vocalizations, auditory processing and hypersensitivity, and socialization. We propose to confirm that several features of the behavioral phenotype of PWS may be explained within the context of a dysfunctional SES (Specific Aim I), which may be partially rehabilitated via an intervention designed as a 'neural exercise' of the SES (Specific Aim II). Specific Aims: Aim I: To demonstrate that children with PWS have atypical regulation of the SES. We hypothesize these effects will be manifested by dampened vagal regulation of the heart (low parasympathetic tone); poor middle ear muscle regulation resulting in auditory hypersensitivities and poor auditory processing; lack of voice intonation (prosody), and difficulties in accurately detecting the emotions of others. Aim II: To demonstrate the effectiveness of the Listening Project Protocol (LPP) in decreasing the atypical features of the SES in adolescents with PWS. We hypothesize that individuals who complete the LPP will have improved vagal regulation of the heart, improved middle ear muscle regulation, increased voice intonation and improved ability to accurately detect the emotions of others.

Polyvagal Theory, Respiratory Sinus Arrhythmia, Heart rate, Social Behavior, Arginine Vasopressin, Dichotic Listening Tests, Oxytocin, Hyperacusis, Affect, Auditory perception, Sound spectrography

All participants will participate in pre-intervention assessments (6 months, 1 week prior) and post-intervention assessments (1 week, 1 month post). The Filtered Music Intervention (i.e., Listening Project Protocol) will last for 1 hour per day, for 5 consecutive days.

The filtered music intervention will consist of listening to computer-altered acoustic stimulation, designed to modulate the frequency band of vocal music passed to the participant. The frequency characteristics of the acoustic stimulation are selected to emphasize the relative importance of specific frequencies in conveying the information embedded in human speech Modulation of the acoustic energy within the frequencies of human voice, similar to an exaggerated vocal prosody, are hypothesized to recruit and modulate the neural regulation of the middle ear muscles and to functionally reduce sound hypersensitivities and improve auditory processing.

Inclusion Criteria: Participants must be current residents at Latham Centers (LC) School in Brewster MA Participants must meet criteria for Prader-Willi Syndrome Participants must be between ages 13 - 25 years Participants must have normal hearing Participants must have normal vision (or corrected vision) Exclusion Criteria: Individuals with current (or a history of) heart disease Individuals who are hearing-impaired Individuals who are being treated for seizure disorder Individuals who do not read/speak English Individuals who are sight-impaired without correction

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