Whitwell, Jennifer L.

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.

We aimed to determine whether there is an association between teaching and the development of progressive speech and language disorders (SLDs). Occupation was compared between 100 patients with a progressive SLD, 404 patients with Alzheimer’s dementia, and the 2008 US census. In SLDs, the most common occupation was teacher (22%) versus 8% in Alzheimer’s dementia. The odds ratio (OR) of being a teacher in SLDs compared to Alzheimer’s dementia was 3.4 (95% confidence interval [CI] = 1.87-6.17). No differences were observed in the frequency of other occupations. The frequency of teachers was higher in SLDs compared to the US census, OR of 6.9 (95% CI = 4.3-11.1). Farming, forestry, and fishing occupations were more frequent in SLDs compared to the US census. We identified an association between progressive SLDs and the occupation of teaching. Since teaching is a communication demanding occupation, teachers may be more sensitive to the development of speech and language impairments.

Background and purposePrimary progressive apraxia of speech, a motor speech disorder of planning and programming, is a tauopathy that has overlapping histological features with progressive supranuclear palsy. We aimed to compare, for the first time, atrophy patterns, as well as white matter tract degeneration, between these two syndromes.MethodsSixteen primary progressive apraxia of speech subjects were age‐ and gender‐matched to 16 progressive supranuclear palsy subjects and 20 controls. All subjects were prospectively recruited, underwent neurological and speech evaluations and 3.0‐Tesla magnetic resonance imaging. Grey and white matter atrophy was assessed using voxel‐based morphometry and atlas‐based parcellation, and white matter tract degeneration was assessed using diffusion tensor imaging.ResultsAll progressive supranuclear palsy subjects had typical oculomotor/gait impairments, but none had speech apraxia. Both syndromes showed grey matter loss in supplementary motor area, white matter loss in posterior frontal lobes and degeneration of the body of the corpus callosum. Whilst lateral grey matter loss was focal, involving superior premotor cortex, in primary progressive apraxia of speech, loss was less focal extending into prefrontal cortex in progressive supranuclear palsy. Caudate volume loss and tract degeneration of superior cerebellar peduncles were also observed in progressive supranuclear palsy. Interestingly, area of the midbrain was reduced in both syndromes compared to controls, although this was greater in progressive supranuclear palsy.ConclusionsAlthough neuroanatomical differences were identified between these distinctive clinical syndromes, substantial overlap was also observed, including midbrain atrophy, suggesting these two syndromes may have common pathophysiological underpinnings.