Spatial Characteristics of Jaw Movements During Chewing in Children with Cerebral Palsy: A Pilot Study.

This study compared jaw motion between children with cerebral palsy (CP) and their typically-developing (TD) peers during chewing. The jaw movements of 11 children with spastic CP (GMFCS levels II-V) all of whom were exclusively oral feeders with no reported clinical issues with feeding [mean age = 7.49 (2.30) years; 7 males, 4 females] and 11 age- and sex-matched TD peers [mean age = 7.54 (2.35) years] were recorded using optical motion capture. Participants chewed five trials of three different consistencies, including puree, mechanical soft, and solid. For each chewing sequence, the path distance (total amount of distance traveled by the jaw), average jaw speed, and working space (total 3-dimensional size of the jaw movements during chewing) were calculated. The CP group had greater path distances for mechanical soft and solids (p < 0.001) and larger working spaces (p < 0.001) than the TD group. Consistency differences were also found with path distances increasing for both groups with increased bolus consistency (p < 0.001). Puree was chewed most slowly for both groups (p = 0.05) and was associated with smaller working space than the other consistencies for both groups (p < 0.001). The TD group demonstrated slower speeds for mechanical soft as compared to solids (p = 0.05), a finding which was not observed in the CP group. The results suggest children with CP showed jaw movement differences during chewing despite being exclusive oral eaters with no reports of clinical feeding or deglutition disorders. Food consistency also influenced jaw movements in both children with CP and their TD peers.

Autonomic Nervous System Responses to Hearing-Related Demand and Evaluative Threat.

PURPOSE: This paper consists of 2 parts. The purpose of Part 1 was to review the potential influence of internal (person-related) factors on listening effort. The purpose of Part 2 was to present, in support of Part 1, preliminary data illustrating the interactive effects of an external factor (task demand) and an internal factor (evaluative threat) on autonomic nervous system measures. METHOD: For Part 1, we provided a brief narrative review of motivation and stress as modulators of listening effort. For Part 2, we described preliminary data from a study using a repeated-measures (2 × 2) design involving manipulations of task demand (high, low) and evaluative threat (high, low). The low-demand task consisted of repetition of sentences from a narrative. The high-demand task consisted of answering questions about the narrative, requiring both comprehension and recall. During the high evaluative threat condition, participants were filmed and told that their video recordings would be evaluated by a panel of experts. During the low evaluative threat condition, no filming occurred; participants were instructed to "do your best." Skin conductance (sympathetic nervous system activity) and heart rate variability (HRV, parasympathetic activity) were measured during the listening tasks. The HRV measure was the root mean square of successive differences of adjacent interbeat intervals. Twelve adults with hearing loss participated. RESULTS: Skin conductance increased and HRV decreased relative to baseline (no task) for all listening conditions. Skin conductance increased significantly with an increase in evaluative threat, but only for the more demanding task. There was no significant change in HRV in response to increasing evaluative threat or task demand. CONCLUSIONS: Listening effort may be influenced by factors other than task difficulty, as reviewed in Part 1. This idea is supported by the preliminary data indicating that the sympathetic nervous system response to task demand is modulated by social evaluative threat. More work is needed to determine the relative contributions of motivation and emotional stress on physiological responses during listening tasks.