Aging-related geniohyoid muscle atrophy is related to aspiration status in healthy older adults

Abstract

Background: Age-related muscle weakness due to atrophy and fatty infiltration in orofacial muscles may be related to swallowing deficits in older adults. An important component of safe swallowing is the geniohyoid (GH) muscle, which helps elevate and stabilize the hyoid bone, thus protecting the airway. This study aimed to explore whether aging and aspiration in older adults were related to GH muscle atrophy and fatty infiltration.

Method: Eighty computed tomography scans of the head and neck from 40 healthy older (average age 78 years) and 40 younger adults (average age 32 years) were analyzed. Twenty aspirators and 20 nonaspirators from the 40 older adults had been identified previously. Two-dimensional views in the sagittal and coronal planes were used to measure the GH cross-sectional area and fatty infiltration.

Results: GH cross-sectional area was larger in men than in women (p < .05). Decreased cross-sectional area was associated with aging (p < .05), and cross-sectional area was significantly smaller in aspirators compared with nonaspirators, but only among the older men (p < .01). Increasing fatty infiltration was associated with aging in the middle (p < .05) and posterior (p < .01) portions of the GH muscle. There was no significant difference in fatty infiltration of the GH muscle among aspirators and nonaspirators.

Conclusion: GH muscle atrophy was associated with aging and aspiration. Fatty infiltration in the GH muscle was increased with aging but not related to aspiration status. These findings suggest that GH muscle atrophy may be a component of decreased swallowing safety and aspiration in older adults and warrants further investigation.

Keywords: Aspiration; Atrophy; CT scans.; Fatty infiltration; Geniohyoid muscle; Older adults; Swallow.

Figure 1.

Two-dimensional computed tomography (CT) scans used for measurements of the geniohyoid (GH) muscle. (A) is the section in midsagittal plane; (B) is an enlargement of the white square in (A). (B) also shows axis of the longitudinal GH muscle between the mandible and hyoid bone drawn at the one-third (1), middle (2), and two-thirds (3) portions of the GH muscle in the midsagittal plane. These represent the anterior (C), middle (D), and posterior (E) portions of the GH muscle in the coronal plane. Fatty infiltration index, in Hounsfield units (Hhs), was measured separately for three sections (C–E). GG = genioglossus muscle, A = anterior digastric muscle, and M = mylohyoid muscle.

Figure 2.

Changes in geniohyoid (GH) muscle size associated with aging. Cross-sectional area (CSA) of GH muscle in older adults compared with younger adults in both men and women in the midsagittal (A) or anterior (B) or middle (C) sections of the coronal planes. *—indicates p < .05 and **— indicates p < .01.

Figure 3.

Geniohyoid (GH) muscle size among older adults who were aspirators (black bars) vs nonaspirators (white bars), showing cross-sectional areas (CSA) of the GH muscle in the midsagittal plane (A) and anterior and middle portions of the coronal planes in (B) and (C). *—indicates p < .05 and **—indicates p < .01.

Figure 4.

Fatty infiltration of the anterior, middle, and posterior portions of the geniohyoid (GH) muscle. (A) Effect of aging on these associations in older (black bars) vs younger (white bars) participants. (B) Effects of aspiration on these associations in aspirators (black bars) vs nonaspirators (white bars). Fatty infiltration measured in Hounsfield units (HU). **—indicates p < .01.