Naoko Mitani

This study aimed to identify the neuroanatomical predictors of oropharyngeal dysphagia and tube dependency in patients with supratentorial or infratentorial ischemic strokes. Patients with acute ischemic stroke were enrolled and were classified into 3 groups: right supratentorial (n = 61), left supratentorial (n = 89), and infratentorial stroke (n = 50). Dysphagia was evaluated by a modified water swallowing test and the Food Intake LEVEL Scale to evaluate oropharyngeal dysphagia and tube dependency, respectively. As two dysphagia parameters, we evaluated the durations from onset of stroke to (1) success in the modified water swallowing test and to (2) rating 7 points or above on the Food Intake LEVEL Scale: patients regained sufficient oral intake and were not tube-dependent. Voxel-based lesion-symptom mapping analysis was performed for a spatially normalized lesion map of magnetic resonance imaging to explore the anatomies that are associated with the two dysphagia parameters for each stroke group. The right precentral gyrus and parts of the internal capsule are associated with oropharyngeal dysphagia. The four supratentorial areas are associated with tube dependency. The dorsal upper medulla is associated with both oropharyngeal dysphagia and tube dependency. These results suggest that supratentorial stroke patients can be tube-dependent due to an impaired anticipatory phase of ingestion. The simultaneous damage in the four supratentorial areas: the inferior part of the precentral gyrus, lenticular nucleus, caudate head, and anterior insular cortex, predicts tube dependency. In contrast, infratentorial stroke patients can be tube-dependent due to oropharyngeal dysphagia caused by lesions in the dorsal upper medulla, damaging the swallowing-related nucleus.

KEY CLINICAL MESSAGE: Apraxia of speech (AOS) due to a postcentral infarction differs from conventional precentral AOS with respect to phonemic errors (phoneme substitution) which are more common than phonetic errors (phoneme distortion) and preserved accent and intonation. ABSTRACT: Clinical features of apraxia of speech caused by lesions in the postcentral gyrus have not yet been elucidated. Here, we report a patient with this lesion and show how postcentral apraxia of speech differs from the hitherto known precentral apraxia of speech. A 54-year-old man developed Broca's aphasia with apraxia of speech that resolved into pure apraxia of speech within 3 weeks following infarction of the postcentral gyrus. The diagnosis of apraxia of speech was based on the patient's effortful, slow speech and inconsistent phonetic distortions with phonemic paraphasia. The Western Aphasia Battery was used to examine the patient's speech samples. Speech was recorded using a digital voice recorder and transcribed into a narrow transcription of the International Phonetic Alphabet. The error types were categorized phonologically. The results revealed that (a) phonemic errors (vowel and consonant substitutions, also known as phonemic paraphasia) were more common than phonetic errors (vowel and consonant distortions). Similar to conduction aphasia, phonemic errors were more pronounced in confrontation naming than in repetition, accompanied by self-correction, and (b) word accent and sentence intonation were preserved, although the speech was slow. These two features are characteristic of postcentral apraxia of speech, which can be differentiated from conventional precentral apraxia of speech.