Duffy, Joseph R.

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.

Abstract Background Microbleeds have been associated with Alzheimer's disease (AD), although it is unclear whether they occur in atypical presentations of AD, such as the logopenic variant of primary progressive aphasia (lvPPA). We aimed to assess the presence and clinical correlates of microbleeds in lvPPA. Methods Thirteen lvPPA subjects underwent 3T T2*‐weighted and fluid‐attenuated inversion recovery magnetic resonance imaging and Pittsburgh compound B (PiB) positron emission tomography imaging. Microbleeds were identified on manual review and assigned a regional location. Total and regional white matter hyperintensity (WMH) burden was measured. Results Microbleeds were observed in four lvPPA subjects (31%), most commonly in the frontal lobe. Subjects with microbleeds were older, more likely female, and had a greater burden of WMH than those without microbleeds. The regional distribution of microbleeds did not match the regional distribution of WMH. All cases were PiB positive. Conclusions Microbleeds occur in approximately one third of subjects with lvPPA, with older women at the highest risk.

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.

Purpose To discuss apraxia of speech (AOS) as it occurs in neurodegenerative disease (progressive AOS [PAOS]) and how its careful study may contribute to general concepts of AOS and help refine its diagnostic criteria. Method The article summarizes our current understanding of the clinical features and neuroanatomical and pathologic correlates of PAOS and its relationship to primary progressive aphasia (PPA). It addresses similarities and differences between PAOS and stroke-induced AOS that may be relevant to improving our understanding of AOS in general. Conclusions PAOS is clinical disorder that should be distinguished from PPA. Its recognition is important to clinical care provided by speech-language pathologists, but it also has implications for neurologic localization and diagnosis as well as prediction of underlying pathology and histochemistry. The clinical features of PAOS and stroke-induced AOS have not been explicitly compared, but they may not be identical because PAOS does not follow a vascular distribution, the brunt of cortical pathology is in the premotor and supplementary motor area, and its onset (rather than acute) is slowly progressive with potential for adaptation to gradual impairment. Careful description and study of PAOS may be a valuable source of information for refining our understanding of AOS in general.

Purpose This study’s main purpose was to (a) identify acoustic signatures of hypokinetic dysarthria (HKD) that are robust to phonetic variation in conversational speech and (b) determine specific characteristics of the variability associated with HKD. Method Twenty healthy control (HC) participants and 20 participants with HKD associated with idiopathic Parkinson’s disease (PD) repeated 3 isolated sentences (controlled phonetic content) and 2 min of conversational speech (phonetic content treated as a random variable). A MATLAB-based program automatically calculated measures of contrastivity: speech–pause ratio, intensity variation, median and maximum formant slope, formant range, change in the upper and lower spectral envelope, and range of the spectral envelope. t tests were used to identify which measures were sensitive to HKD and which measures differed by task. Discriminant analysis was used to identify the combination of measures that best predicted HKD, and this analysis was then used as a general measure of contrastivity (Contrastivity Index). Differential effects of HKD on maximum and typical contrastivity levels were tested with interaction of maximum, minimum, and median observations of individual speakers and with pairwise comparisons of skewness and kurtosis of the contrastivity index distributions. Results Group differences were detected with pairwise comparisons with t tests in 8 of the 9 measures. Percentage pause time and spectral range were identified as the most specific (95%) and accurate (95%) differentiators of HKD and HC conversational speech. Sentence repetition elicited significantly higher levels of contrastivity than conversational speech in both HC and HKD speakers. Maximum and minimum contrastivities were significantly lower in HKD speech, but there was no evidence that HKD affects maximum contrastivity levels more than median contrastivity levels. The HKD speakers' contrastivity distributions were significantly more skewed to lower levels of production. Conclusion HKD can be consistently distinguished from HC speech in both sentence repetition and conversational speech on the basis of intensity variation and spectral range. Although speakers with HKD were effectively able to produce higher contrastivity levels in sentence repetition tasks, they habitually performed closer to the lower end of their production ranges.