Development of functional synergies for speech motor coordination in childhood and adolescence

Abstract

Adults produce rapid, interleaved sequences of speech sounds by controlling the relative motions in time and space of the oral articulators. The control and coordination of these effectors appear to be automatic, effortless, and usually error free. If speech production is viewed within the framework of classical motor control theories, we can infer that adults have organized functional synergies (consistent patterns of activation of muscle collectives) that act as stable subunits. In this study, the development of these stable functional synergies is examined. Motion of the upper lip, lower lip, and jaw was recorded during sentence production in 180 children and adults (aged 4-22 years). Two indices of oral motor coordination were computed, which reflect the degree of trial-to-trial consistency in intereffector relationships and thus the stability of the underlying functional synergies. Major findings are: (a) The time course of development for speech motor coordination is protracted, (b) speech motor control processes are not adultlike until after age 14 years for both females and males, (c) boys (until age 5 years) show a slower maturational course of speech motor development, and (d) late childhood (the 7- to 12-year period) is characterized by a plateau in the development of these coordinative synergies for speech production. We posit that multiple factors are likely to contribute to the protracted development of oral motor coordination for speech, including maturation of components of the motor system itself and maturation of the brain subsystems for language processing.

Influence of adenotonsillar hypertrophy on /s/-articulation in children—effects of surgery

“…This is not surprising since girls are known to have an earlier maturation of motor skills in general and speech articulation in particular (Smith and Zelanik, 2004). It is also in line with the previous study of non speech oral motor function of the same material where boys were more negatively affected by tonsillar hypertrophy ).…”

Respiratory, postural and spatio-kinetic motor stabilization, internal models, top-down timed motor coordination and expanded cerebello-cerebral circuitry: a review

“…This is reflected in the continued motor control refinement in bipedality, dexterity and vocalization (Assaiante and Amblard, 1995;Choudhury et al, 2007;Hirschfed and Forssberg, 1992;Smith and Zelaznik, 2004) that occurs into late adolescence, and the fact that the acquisition of specialized hand skills (tool making, tool using and accurate throwing) can require at least ten years of daily practice if they are to be mastered at an expert level of motor competence (Ericsson and Lehmann, 1996). This need for a prolonged duration of human motor function is also known to be closely linked to the brain's neurological development and so the evolution of the human brain protracted maturation (Skoyles, 2008).…”

“…Notably, even seemingly simple and universal skills such as walking, talking and fine-finger dexterity continue to mature during adolescence (Assaiante and Amblard, 1995;Choudhury et al, 2007;Hirschfed and Forssberg, 1992;Smith and Zelaznik, 2004). Moreover, highly specialized and culturally dependent motor skills such as those in music playing also require continuous daily attentive practice for at least ten years (Ericsson and Lehmann, 1996), and this produces MRI detectable changes in the brain (Amunts et al, 1997;Elbert et al, 1995;Hutchinson et al, 2003;Schlaug et al, 1995).…”

Diadococinesia sequencial em crianças fluentes e com gagueira desenvolvimental persistente: análise da velocidade e tipo do erro da consoante alvo

“…Speed may be understood as a measure of the amount of speech produced in a given time. Speech smoothness is the result of motor production and transition performed effortlessly (a unified motor program which selects the proper phonemes, at the correct time and order, with no attention required to do it) (10,11,12) . Fluency and smoothness of speech result from practice and learning.…”

“…Fluency and smoothness of speech result from practice and learning. As the motor programs are created, corrected, and repeated, those actions become natural (the motor command is generated, muscle interactions are organized, there is less need for system control, and less effort demanded) (10,11,12) . One of the best-known fluency disorders is persistent developmental stuttering.…”