オトガイ舌骨筋の加齢萎縮と誤嚥

オトガイ舌骨筋の加齢による萎縮は誤嚥と関連するという論文を紹介します。加齢によるサルコペニアの嚥下障害をみた論文です。

Xin Feng, et al. Aging-Related Geniohyoid Muscle Atrophy Is Related to Aspiration Status in Healthy Older Adults. J Gerontol A Biol Sci Med Sci (2012) doi: 10.1093/gerona/gls225 First published online: October 30, 2012

オトガイ舌骨筋の筋萎縮と脂肪浸潤をCTで評価しています。対象は健常高齢者40人（誤嚥あり20人、誤嚥なし20人）と若年者40人です。

結果ですが、オトガイ舌骨筋の横断面積は男性のほうが女性より大きかったです。横断面積の減少は加齢と関連していました。男性では誤嚥ありの高齢者では誤嚥なしの高齢者より、横断面積が小さい結果でした。脂肪浸潤は中部と後部で加齢に関連していましたが、誤嚥の有無とは関連を認めませんでした。

以上よりオトガイ舌骨筋の筋萎縮は、加齢と誤嚥と関連するという結論です。脂肪浸潤は加齢に関連しますが、誤嚥と関連しません。オトガイ舌骨筋の筋萎縮は、高齢者の嚥下機能低下と誤嚥の原因の1つかもしれませんが、さらなる調査が必要です。

サルコペニアの嚥下障害を研究する上で、嚥下筋の筋肉量を定量的に評価することが重要です。この研究ではCTを用いており、やはりゴールドスタンダードはCTかMRIでしょう。超音波で評価している論文もありますが、信頼性、妥当性がやや劣るかもしれません。

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.