Citations

Background and purposeA subset of patients with Alzheimer's disease (AD) present with early and prominent language deficits. It is unclear whether the burden of underlying β‐amyloid pathology is associated with language or general cognitive impairment in these subjects.MethodsThe relationship between cortical β‐amyloid burden on [11C]Pittsburgh compound B (PiB) positron emission tomography (PET) and performance on the Montreal Cognitive Assessment (MoCA), the Wechsler Memory Scale − Third Edition (WMS‐III), the Boston Naming Test (BNT) and the Western Aphasia Battery (WAB) was assessed using regression and correlation analyses in subjects presenting with aphasia who showed β‐amyloid deposition on PiB PET.ResultsThe global PiB ratio was inversely correlated with MoCA (P = 0.02) and the WMS‐III Visual Reproduction (VR) subtest (VR I, P = 0.02; VR II, P = 0.04). However, the correlations between PiB ratio, BNT (P = 0.13), WAB aphasia quotient (P = 0.11) and WAB repetition scores (P = 0.34) were not significant.ConclusionThis study demonstrates that an increased cortical β‐amyloid burden is associated with cognitive impairment, but not language deficits, in AD subjects presenting with aphasia. The results suggest that β‐amyloid deposition could be partly contributing to impaired cognition in such patients whilst language dysfunction may be more influenced by other pathological mechanisms, perhaps downstream pathways of β‐amyloid deposition.

Background and purposeTo describe speech, neurological and imaging characteristics of a series of patients presenting with progressive spastic dysarthria as the first and predominant sign of a presumed neurodegenerative disease.MethodsParticipants were 25 patients with spastic dysarthria as the only or predominant speech disorder. Clinical features, pattern of MRI volume loss on voxel‐based morphometry and pattern of hypometabolism on F18‐fluorodeoxyglucose positron emission tomography (FDG‐PET) scan are described.ResultsAll patients demonstrated speech characteristics consistent with spastic dysarthria, including strained voice quality, slow speaking rate, monopitch and monoloudness, and slow and regular speech alternating motion rates. Eight patients did not have additional neurological findings on examination. Pseudobulbar affect, upper motor neuron pattern limb weakness, spasticity, Hoffman sign and positive Babinski reflexes were noted in some of the remaining patients. Twenty‐three patients had electromyographic assessment and none had diffuse motor neuron disease or met El Escorial criteria for amyotrophic lateral sclerosis. Voxel‐based morphometry revealed striking bilateral white matter volume loss affecting the motor cortex (BA 4), including the frontoparietal operculum (BA 43) with extension into the middle cerebral peduncle. FDG‐PET showed subtle hypometabolism affecting the premotor and motor cortices in some patients, particularly in those who had a disease duration longer than 2 years.ConclusionsA neurodegenerative disorder that begins focally with spastic dysarthria due to involvement of the motor and premotor cortex and descending corticospinal and corticobulbar pathways is characterized. The descriptive label ‘progressive spastic dysarthria’ to best capture the dominant presenting feature of the syndrome is proposed.