Neurophysiological responses to music and vibroacoustic stimuli in Rett syndrome.

People with Rett syndrome (RTT) have severe communicative difficulties. They have as well an immature brainstem that implies dysfunction of the autonomic nervous system. Music plays an important role in their life, is often used as a motivating tool in a variety of situations and activities, and caregivers are often clear about people with RTTs favourites. The aim of this study was to investigate physiological and emotional responses related to six different musical stimuli in people with RTT. The study included 29 participants with RTT who were referred to the Swedish Rett Center for medical brainstem assessment during the period 2006-2007. 11 children with a typical developmental pattern were used as comparison. A repeated measures design was used, and physiological data were collected from a neurophysiological brainstem assessment. The continuous dependent variables measured were Cardiac Vagal Tone (CVT), Cardiac Sensitivity to Baroreflex (CSB), Mean Arterial Blood Pressure (MAP) and the Coefficient of Variation of Mean Arterial Blood Pressure (MAP-CV). These parameters were used to categorise brainstem responses as parasympathetic (calming) response, sympathetic (activating) response, arousal (alerting) response and unclear response. The results showed that all participants responded to the musical stimuli, but not always in the expected way. It was noticeable that both people with and without RTT responded with an arousal to all musical stimuli to begin with. Even though the initial expressions sometimes changed after some time due to poor control functions of their brainstem, the present results are consistent with the possibility that the RTT participants' normal responses to music are intact. These findings may explain why music is so important for individuals with RTT throughout life.

How facial expressions in a Rett syndrome population are recognised and interpreted by those around them as conveying emotions.

Rett syndrome (RTT) is a neurodevelopmental disorder, including autonomic nervous system dysfunctions and severe communication impairment with an extremely limited ability to use verbal language. These individuals are therefore dependent on the capacity of caregivers to observe and interpret communicative signals, including emotional expressions. People in general, including therapists tend to focus on changes in facial expressions to interpret a person's emotional state or choices, but with this population it is difficult to know if the interpretations are correct. The aims of this study were to investigate if the Facial Action Coding System (FACS) could be used to identify facial expressions, and differentiate between those that expressed emotions and those that were elicited by abnormal brainstem activation in RTT. The sample comprised 29 participants with RTT and 11 children with a normal developmental pattern, exposed to six different musical stimuli during non-invasive registration of autonomic brainstem functions. The results indicate that FACS makes it possible both to identify facial expressions and to differentiate between those that stem from emotions and those caused by abnormal brainstem activation. This knowledge may be a great help to an uninitiated observer, who otherwise might incorrectly interpret the latter as an expression of emotion.