A speech expression disorder in patients with severe diffuse brain injury who emerged from a vegetative or minimally conscious state

Abstract

Objective: The purpose of this study was to highlight a speech expression disorder considered as a mixed speech apraxia (SA) and dysarthria syndrome in patients with chronic severe diffuse brain injury (DBI) and to determine its correlation with anatomical localizations of brain lesions using neuroimaging.

Methods: Among 140 patients with chronic severe DBI, eight showed this type of speech disorder. MRI (five patients) and FDG-PET (six patients) procedures were performed.

Results: Affected patients could comprehend verbally, read words silently and express words using a word board. Compared with SA, the disorder is characterized by similarities in regards to reduced phonation and marked facio-oral apraxia, but by distinct differences in terms of an accompanying dysphagia and pyramidal/extra-pyramidal symptoms that are similar to symptoms associated with dysarthria due to pseudobulbar palsy. Diffuse regions of the white matter including the left arcuate fasciculus (AF) were significantly decreased in fractional anisotropy value. However, there was no significant cortical metabolic damage in FDG-PET.

Conclusions: The observed speech disorder in these patients is a characteristic entity related to dysfunction of speech expression and may be attributable to damage of not only the AF but also a number of fibres that are related to dysarthria, cognitive and emotional impairments and pyramidal/extra-pyramidal symptoms.

• Diffuse brain injury
• speech apraxia
• dysarthria
• magnetic resonance imaging
• PET