Low dimensional temporal organization of spontaneous eye blinks in adults with developmental disabilities and stereotyped movement disorder

Abstract

This study investigated the mean rate and time-dependent sequential organization of spontaneous eye blinks in adults with intellectual and developmental disability (IDD) and individuals from this group that were additionally categorized with stereotypic movement disorder (IDD+SMD). The mean blink rate was lower in the IDD+SMD group than the IDD group and both of these groups had a lower blink rate than a contrast group of healthy adults. In the IDD group the n to n+1 sequential organization over time of the eye blink durations showed a stronger compensatory organization than the contrast group suggesting decreased complexity/dimensionality of eye-blink behavior. Very low blink rate (and thus insufficient time series data) precluded analysis of time-dependent sequential properties in the IDD+SMD group. These findings support the hypothesis that both IDD and SMD are associated with a reduction in the dimension and adaptability of movement behavior and that this may serve as a risk factor for the expression of abnormal movements. KeywordsStereotypic movement disorders; eye blinks, intellectual and developmental disabilities Stereotypic movement disorders (SMD) are particularly prevalent in individuals with intellectual and developmental disability (IDD) (Baumeister & Forehand, 1973;Cooper & Dourish, 1990; Sprague & Newell, 1996), though stereotypy is also evident in a number of other population groups and species, including human infants (Thelen, 1996) and caged animals (Berkson, 1967;Mason & Rushen, 2007). The pathophysiological basis of stereotypies in neurodevelopmental disorders is not well understood. There is growing evidence, however, Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptRes Dev Disabil. Author manuscript; available in PMC 2011 January 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript that these behaviors are associated with alterations in cortical-basal ganglia circuitry (Lewis, Tanimura, Lee, & Bodfish, 2007). This is consistent with long-standing observations that dopamine agonists (e.g., amphetamine) acting on the basal ganglia reliably induce stereotyped behavior in a wide range of animal species (see Cooper & Dourish, 1990). In addition, stereotyped behavior that has been shown to be a predictable consequence of early social deprivation in non-human primates was shown to be associated with dopamine receptor supersensitivity (Lewis, Gluck, Beauchamp, Keresztury, & Mailman, 1990), loss of dopamine innervation in striatum and dopamine cells in substantia nigra, and decreases in stria...

Development and temporal organization of repetitive behavior in an animal model

“…To assess temporal organization, we examined the second order property of stereotyped responses, that is, the difference between consecutive inter-response intervals. Lee et al (2010) used the same approach to identify the temporal structure in spontaneous blinking using adjacent interblink intervals. This analysis showed decreased complexity of eye-blinking in individuals with intellectual disability versus controls.…”

“…These investigators showed that intervals between tics were not random and that the temporal structure in the tic time series could be uncovered using several statistical approaches or models. In an intriguing set of studies, Newell et al have shown increased regularity in movements associated with upright postural stability (Bodfish, Parker, Lewis, Sprague, & Newell, 2001), sitting (Newell & Bodfish, 2007), and spontaneous blinking (Lee, Bodfish, Lewis, & Newell, 2010) in individuals with neurodevelopmental disorders who engaged in stereotyped behavior versus matched controls. Finally, as far as we are aware, there has been no attempt to address the intriguing question of whether such temporal characteristics interact with developmental trajectory.…”