An etiologic concept linking an impaired axial motor control system to the structural deformity of idiopathic scoliosis (ISc) is proposed. Postural studies reveal that during quiet stance, adaptation is marked in conditions associated with visual control of sway, particularly of lateral sway; during imposed perturbations of the body, destabilized postural reactions are pronounced in tests requiring visual-vestibular coupling. Observations of visual and/or vestibular generated eye movements indicate ocular instability among a high proportion of the ISc. Previously, the authors argued that a direct relationship exists between visual and/or vestibular functioning and a disordered axial motor system. This was attributed to an aberrant brain stem mechanism. In this presentation, however, we propose that a higher level CNS disturbance may be responsible for reports of EEG abnormalities, visuo-spatial impairment, motor adaptation, and learning deficits. Among the wide range of visual-vestibular variables studied, those representing processing of vestibular signals within the CNS yield the highest degree of correlation with the magnitude of the curve. Moreover, differences in vestibular processing between two subsets of ISc, namely ISc with (70%) and without (30%) normal academic achievement are significant. Variables referable to both vestibular and visual processing correctly classify 87% of the ISc with normal academic achievement and 100% of the ISc with a history of academic problems. The association between learning deficits, altered processing of vestibular information, and ISc suggest a unique syndrome complex, and an important role of cortical structures in the etiology of this disorder. The presence of a visuo-spatial perceptual impairment may be the common feature of ISc. In an attempt to restore perceptual dysfunction (by rearrangement), the ISc adopts a new axial and vestibular motor control strategy based upon recalibration or reinterpretation of proprioceptive signals arising from the axial musculature.

Adaptation, Physiological↗

PubMedDate not supplied

Linguistic models of F0 use, physiological models of F0 control, and the issue of "mean response time".

This paper evaluates "mean response time" (MRT), a method used in previous studies to relate physiological evidence (recordings of electromyographic activity in the cricothyroid and sternohyoid) to acoustic evidence (fundamental frequency). Rather than averaging over tokens before correlating these signals, we calculated the best response time (RT) for each token, and evaluated the pattern of variability across utterances. Furthermore, rather than correlating over whole utterances, we correlated electromyographic activity (EMG) to fundamental frequency (F0) only over intervals defined in terms of linguistically significant events in the F0 trace, identified using a linguistically motivated model of English intonation. Steep changes in the F0 tended to have better correlation coefficients than shallow ones, which we relate to the physiological model by noting the complex of components contributing to both signal types. Also, the distribution of lead times was easier to interpret when the two tones delimiting the analysis domain had some tight temporal relationship specified by the intonational phonology. Finally, lead times tended to vary as a function of what preceded the target rise or fall. In short, averaging over signals before analysis obscures patterns of variation in the data which may lead to new insights and to new directions for research.

Electromyography↗

PubMedDate not supplied

Defending the mentally disabled.

Explore the source record for details and available documents.

Deinstitutionalization↗

PubMedDate not supplied

How government policy decisions affect seniors' quality of life: findings from a participatory policy study carried out in Toronto, Canada.

Toronto seniors explored how government policy decisions were influencing their health and well-being. In this participatory policy study, emphasis was upon the lay and critical knowledge of highly informed seniors. Focus groups and interviews revealed that all three levels of governments were seen as not listening to seniors' voices. In nine key policy areas identified as influencing seniors' quality of life--hearing seniors' voices, housing, acute illness care, long-term care, income supports, transportation and mobility, promoting healthy lifestyles, access to information, and hearing voices from cultural communities--many concerns were raised. The gap between government rhetoric and government action on seniors' issues merits public health attention.

Aged↗