Development of Chewing in Children From 12 to 48 Months: Longitudinal Study of EMG Patterns

Department of Speech and Hearing Sciences, University of Washington, Seattle 98105-6246, USA.
Journal of Neurophysiology (Impact Factor: 2.89). 06/1997; 77(5):2704-16.
Source: PubMed


Developmental changes in the coordinative organization of masticatory muscles were examined longitudinally in four children over 49 experimental sessions spanning the age range of 12-48 mo. Electromyographic (EMG) records were obtained for right and left masseter muscles, right and left temporalis muscles, and the anterior belly of the digastric. Two independent analytic processes were employed, one that relied on identification of onset and offset of muscle activation and a second that used pairwise cross-correlational techniques. The results of these two analyses, which were found to be consistent with each other, demonstrated that the basic chewing pattern of reciprocally activated antagonistic muscle groups is established by 12 mo of age. Nevertheless, chewing efficiency appears to be improved through a variety of changes in the chewing pattern throughout early development. Coupling of activity among the jaw elevator muscles was shown to strengthen with maturation, and the synchrony of onset and offset of these muscles also increased. Coactivation of antagonistic muscles decreased significantly with development. This decrease in antagonistic coactivation and increase in synchrony among jaw elevators, and a parallel decrease in EMG burst duration, were taken as evidence of increased chewing efficiency. No significant differences in the frequency of chewing were found across the ages studied. Additional considerations include the appropriateness of this coordinative infrastructure for other developing oromotor skills, such as speech production. It is suggested that the relatively fixed coordinative framework for chewing exhibited by these children would not be suitable for adaptation to speech movements, which have been shown to rely on a much more variable and adjustable coordinative organization.

Download full-text


Available from: Christopher A Moore,
  • Source
    • "Extensive study of developing speech behaviors has described the physiologic framework of early and later speech acquisition (Connaghan, Moore, & Higashakawa, 2004; Goffman, 1999; Green, Moore, Higashikawa, & Steeve, 2000; Green, Moore, & Reilly, 2002; Green et al., 1997; Green & Wilson, 2006; Moore, Caulfield, & Green, 2001; Moore & Ruark, 1996; Ruark & Moore, 1997; Smith & Zelaznik, 2004; Steeve & Moore, 2009; Walsh, Smith, & Weber-Fox, 2006; Wohlert & Smith, 2002). Using palatography and electromagnetic articulography, lingual gestures produced by older children (i.e., older than 9 years) with persistent speech sound errors have been shown to be distinct from those of their typically developing peers (Gibbon, 1999; Gibbon & Wood, 2002; Goozee, et al., 2007), providing support for the notion that speech motor control differences are associated with some SSD. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: The purpose of the study was to determine whether distinct subgroups of preschool children with speech sound disorders (SSD) could be identified using a subgroup discovery algorithm (SUBgroup discovery via Alternate Random Processes, or SUBARP). Of specific interest was finding evidence of a subgroup of SSD exhibiting performance consistent with atypical speech motor control. Method: Ninety-seven preschool children with SSD completed speech and nonspeech tasks. Fifty-three kinematic, acoustic, and behavioral measures from these tasks were input to SUBARP. Results: Two distinct subgroups were identified from the larger sample. The 1st subgroup (76%; population prevalence estimate = 67.8%-84.8%) did not have characteristics that would suggest atypical speech motor control. The 2nd subgroup (10.3%; population prevalence estimate = 4.3%-16.5%) exhibited significantly higher variability in measures of articulatory kinematics and poor ability to imitate iambic lexical stress, suggesting atypical speech motor control. Both subgroups were consistent with classes of SSD in the Speech Disorders Classification System (SDCS; Shriberg et al., 2010a). Conclusion: Characteristics of children in the larger subgroup were consistent with the proportionally large SDCS class termed speech delay; characteristics of children in the smaller subgroup were consistent with the SDCS subtype termed motor speech disorder-not otherwise specified. The authors identified candidate measures to identify children in each of these groups.
    Journal of Speech Language and Hearing Research 07/2014; 57(6). DOI:10.1044/2014_JSLHR-S-12-0193 · 2.07 Impact Factor
  • Source
    • "beef and peanuts) or food with multiple consistencies (e.g. grapes) (Green et al., 1997). Not all children develop this process smoothly or quickly (e.g. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The Mastication Observation and Evaluation (MOE) instrument was developed to allow objective assessment of a child's mastication process. It contains 14 items and was developed over three Delphi rounds. The present study concerns the further development of the MOE using the COSMIN (Consensus based Standard for the Selection of Measurement Instruments) and investigated the instrument's internal consistency, inter-observer reliability, construct validity and floor and ceiling effects. Consumption of three bites of bread and biscuit was evaluated using the MOE. Data of 59 healthy children (6-48 mths) and 38 children (bread) and 37 children (biscuit) with cerebral palsy (24-72 mths) were used. Four items were excluded before analysis due to zero variance. Principal Components Analysis showed one factor with 8 items. Internal consistency was >0.70 (Chronbach's alpha) for both food consistencies and for both groups of children. Inter-observer reliability varied from 0.51 to 0.98 (weighted Gwet's agreement coefficient). The total MOE scores for both groups showed normal distribution for the population. There were no floor or ceiling effects. The revised MOE now contains 8 items that (a) have a consistent concept for mastication and can be scored on a 4-point scale with sufficient reliability and (b) are sensitive to stages of chewing development in young children. The removed items are retained as part of a criterion referenced list within the MOE.
    Research in developmental disabilities 04/2014; 35(7):1551-1561. DOI:10.1016/j.ridd.2014.03.035 · 4.41 Impact Factor
  • Source
    • "Electromyographic studies of mandibular muscle activation patterns have provided perhaps the strongest evidence of increased chewing effectiveness with age (Green et al., 1997; Steeve et al., 2008). For example, older children exhibit the same chewing frequency as younger children but with shorter bursts of muscle activity (Green et al., 1997). "

Show more