Neuromuscular control of masticatory muscles in people with intellectual disability, middle-aged adults and older adults.

BACKGROUND: Motor control issues are common for people with intellectual disabilities (PWID), resulting in difficulties with basic activities of daily living, including eating. Mastication, which is crucial for digestion and overall health, is poorly understood in this population. PWID shows frailty similar to older people, highlighting the importance of comparing masticatory motor control with older adults. This study compared the neuromuscular control of the masticatory muscles in middle-aged, PWID and older adults. METHODS: A cross-sectional analytical design was used. During the mastication task of a carrot piece (2 cm in diameter and weighing 0.5 g), surface electromyography was used to record muscle activity patterns from the right and left masseter and temporalis muscles. Principal component analysis (PCA) was used to assess neuromuscular control. A z-score normalisation of the first component's variance from PCA to identify those individuals with altered neuromuscular control. A mixed ANOVA was performed to assess the interaction between principal components, groups and body composition. RESULTS: Thirty PWIDs (aged 35-55 years), middle-aged adults and 32 older adults were recruited. PWID and older adults showed decreased neuromuscular control of the masticatory muscles compared to middle-aged control adults (P < 0.05). PWID had the highest proportion of individuals with altered neuromuscular control of the masticatory muscle (53%) compared to older adults (19%) and middle-aged adults (0%) (P < 0.05). CONCLUSIONS: Our results indicate that PWID and older adults have reduced neuromuscular control compared to middle-aged adults. Notably, a significant proportion of the PWID showed altered masticatory muscle control compared to older adults. Further research is needed to explore the potential benefits of masticatory muscle training for PWID.

Reduced lip seal strength and missing teeth are associated with poorer masticatory performance in young adults with intellectual disabilities: a cross-sectional analytical study.

BACKGROUND: Alterations in oral health have a negative impact on the quality of life of persons with intellectual disabilities (PwIDs). Chewing is a process that influences and determines optimal oral health. However, little is known about how intellectual disability (ID) affects masticatory performance. This study aimed to analyse the differences in masticatory performance between young adults with IDs, young adults without IDs and older adults without IDs. METHODS: A cross-sectional analytical design was used. The masticatory performance was evaluated with a chewing gum validated instrument. In addition, the labial and tongue strength was assessed with the Iowa Oral Performance Instrument. We compared the masticatory performance between groups using one-way analysis of covariance. Body mass index, muscle mass, missing teeth, lip strength and tongue strength were included as separate covariates. A multivariate regression analysis was performed to identify which independent variables could explain masticatory performance in each group. RESULTS: Thirty-two PwIDs, 31 young adults without IDs and 32 older adults without IDs were recruited. PwIDs showed poorer masticatory performance compared with older adults (mean difference: -3.06, 95% confidence interval: -3.87 to -2.26) and healthy controls (mean difference: -2.38, 95% confidence interval: -3.19 to -1.57). The analysis of covariance showed significant difference between groups in the masticatory performance (F = 47.35, P < 0.001, ηp 2  = 0.507). Missing teeth (P < 0.001), right lip strength (P = 0.025) and tongue strength (P = 0.007) as covariables showed a significant interaction with the model. In the PwID group, lip strength and lack of teeth explained 58% of the variance in masticatory performance (R2  = 0.580, standard error = 1.12, P < 0.001). CONCLUSIONS: Persons with intellectual disabilities have a poorer masticatory performance than adults without IDs. Our findings indicate that the primary determinants of optimal masticatory function in PwIDs are the strength of the lip seal and the number of missing teeth.

Sensory strategies of postural sway during quiet stance in patients with haemophilic arthropathy.

INTRODUCTION: The sensory strategies of postural control in adult haemophilic arthropathy patients are still poorly understood. AIM: To determine sensorial posture-control strategies through postural sway frequency analysis when in a bipedal quiet stance with and without visual stimulus deprivation in healthy subjects and patients with haemophilic arthropathy. Secondarily, to determine the irregularity of postural balance control through sample entropy (SampEn). METHODS: A triaxial accelerometer attached at the L3 level determined the displacement and acceleration of the centre of mass (DCoM and ACoM, respectively) under open- and closed-eyes conditions. Sensorial strategies were studied by spectral analysis of the DCoM signal, divided into low, medium and high frequencies for visual/vestibular, cerebellum and somatosensory strategies respectively. DCoM irregularity was also analysed by SampEn. RESULTS: Fifteen young, healthy subjects and fifteen young, haemophilia patients were included. The mediolateal DCoM and anteroposterior ACoM differed between groups. During the open-eyes condition, haemophiliacs presented limited high and medium frequencies, and more low frequency bands as compared to non-haemophiliacs (P<.05). In the closed-eyes condition, haemophiliacs had a minor percentage of high frequencies but an elevated percentage of low frequencies as compared to non-haemophiliacs (P<.05). Non-haemophiliacs had higher SampEn than haemophiliacs in the mediolateral axis with open- and closed-eyes (P<.05 and <.001, respectively). CONCLUSIONS: The presented results indicate that patients with haemophilic arthropathy, as compared to healthy subjects, have less postural control irregularity and poor somatosensory system contributions that are compensated by more vestibular inputs.