Clinical Characteristics and Lesions Responsible for Swallowing Hesitation After Acute Cerebral Infarction

Abstract

Some stroke patients with a unilateral lesion demonstrate acute dysphagia characterized by a markedly prolonged swallowing time, making us think they are reluctant to swallow. In order to clarify the clinical characteristics and causative lesions of delayed swallowing, we conducted a retrospective analysis of 20 right-handed patients without a history of swallowing dysfunction who underwent videofluorography on suspicion of dysphagia after a first ischemic stroke. The oral processing time plus the postfaucial aggregation time required to swallow jelly for patients classified as having delayed swallowing was over 10 s. The time required for swallowing jelly was significantly longer than that without the hesitation (median value, 24.1 vs. 8.9 s, P < 0.001). The oral processing time plus the postfaucial aggregation time required for patients with delayed swallowing to swallow thickened water was largely over 5 s and significantly longer than that of patients without swallowing hesitation (median value, 10.2 vs. 3.3 s, P < 0.001). Swallowing hesitation caused by acute unilateral infarction could be separated into two different patterns. Because four of the five patients with a rippling tongue movement in the swallowing hesitation pattern had a lesion in the left primary motor cortex, which induces some kinds of apraxia, swallowing hesitation with a rippling tongue movement seems to be a representative characteristic of apraxia. The patients with swallowing hesitation with a temporary stasis of the tongue in this study tended to have broad lesions in the frontal lobe, especially in the middle frontal gyrus, which is thought to be involved in higher cognition.

Keywords: Deglutition; Deglutition disorders; Dysphagia; Hesitation; Swallowing; Videofluorography.

Fig. 1

Diffusion-weighted magnetic resonance imaging (DWI) of three representative cases. a Case 1 demonstrated a left hemisphere lesion including the entire frontal lobe, primary sensory cortex, angular gyrus, and insula. b Case 2 suffered an extended left hemisphere lesion including the entire frontal lobe, primary sensory cortex, angular gyrus, and insula. c Case 3 had a relatively broad infarction including orbitofrontal cortex, inferior frontal gyrus, and insula of the left cerebral hemisphere; however, large parts of the middle frontal gyrus and primary motor cortex were spared

Fig. 2

Speculated neural circuit in swallowing. The middle frontal gyrus serves as an association area between the insula as a sensory center and the middle frontal gyrus as a motor center