Age-Related Differences in Laterality of Cortical Activations in Swallowing

Abstract

The present study examined age differences in neural lateralization patterns during swallowing and three related tasks, using functional magnetic resonance imaging (fMRI). Ten healthy right-handed young adults (mean age = 21.7 years, SD = 2.1 years) and nine healthy elders (mean age = 70.2 years, SD = 3.9 years) were scanned in a 3-T MRI head scanner. Participants were visually cued to "prepare to swallow," "swallow," "tap your tongue," and "clear your throat" in randomized order. Laterality preference for each task was examined within and between groups using region-of-interest (ROI) analyses in seven areas of the left and right primary sensorimotor and premotor cortices. Results of the within-group comparisons verified a more active role of the left premotor cortex in motor-cognitive planning of deglutition in both young and older adults and a more active role of selected areas of the right hemisphere during swallowing in young adults. Greater variability was seen during tongue tapping and throat clearing in both groups. Finally, as people age the cortical hemispheric control of swallowing seems to start becoming more symmetrical/bilateral, which may indicate neural compensatory mechanisms of the aging brain commonly seen for other motor and cognitive functions.

Ressonância magnética funcional e deglutição: revisão sistemática

“…Research on elderly and patients with dysphagia underwent compared to control groups. There was a tendency to use healthy adults for comparison with elderly people (1,26,27) , except in two researches (5,28) . Studies involving dysphagia patients groups or patients with specific diseases were compared with those who evaluated healthy individuals, matched by chronological age and elderly patients (6,(29)(30)(31)(32) .…”

“…A chronological analysis of the presented studies, observed that initially the concern was the confirmation of cortical activation mechanisms for swallowing Therefore, procedures such as saliva (1,3,5,7,(16)(17)(18)(19)(20)22,23,26,(29)(30)(31)(32) , water (5,11,12,17,(24)(25)(26)28,29,31) , barium (5,26,29,31) swallowing were performed, comparing swallow and not swallow (1,7,14,27) . Later on, studies began to analyze differences in the cortical areas, responsible for each motor phase, differentiating the role of the structures involved.…”

“…In an attempt to assess the representativeness of sensory--motor organs, the authors proposed an examination of cortical responses to movements used in rehabilitation procedures, such as orofacial exercises (1,14,21,27) and maneuvers used in rehabilitation (18) . Even on population with dysphagia, they used swallowing of different types of food, such as water (5,(29)(30)(31) , barium (5,29,31) and saliva (5,(29)(30)(31)(32) .…”

“…Guidance provided to different groups of surveyed subjects included visual (3,7,8,10,14,(16)(17)(18)(19)(23)(24)(25)(26)(27)(28)(30)(31)(32) , hearing (6,16,21,29) and sensorial clues (5,9,11,13,15,17,19,24,29) . In studies examining the food swallowing, its ingestion was the track for the patient to swallow, i.e., the absence of formal statement was a major factor, differentiating it from studies with other types of tasks.…”

“…The experiment was considered satisfactory and the suggested tasks suitable to achieve the proposed objectives (7) . The orofacial exercises and tongue, lips and jaw movements have been used in order to monitor the activated cortical areas, serving as a control task for the swallowing analysis (3,14,21,27) . Movements involving the tongue mobility can be used to monitor the activated cortical areas, serving as an important comparative feature between the cortex regions.…”