Duffy, Joseph R.

Background: Different clinical syndromes can arise from Alzheimer’s disease (AD) neuropathology, including dementia of the Alzheimer’s type (DAT), logopenic primary progressive aphasia (lvPPA), and posterior cortical atrophy (PCA). Objective: To assess similarities and differences in patterns of white matter tract degeneration across these syndromic variants of AD. Methods: Sixty-four subjects (22 DAT, 24 lvPPA, and 18 PCA) that had diffusion tensor imaging and showed amyloid-β deposition on PET were assessed in this case-control study. A whole-brain voxel-based analysis was performed to assess differences in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity across groups. Results: All three groups showed overlapping diffusion abnormalities in a network of tracts, including fornix, corpus callosum, posterior thalamic radiations, superior longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and uncinate fasciculus. Subtle regional differences were also observed across groups, with DAT particularly associated with degeneration of fornix and cingulum, lvPPA with left inferior fronto-occipital fasciculus and uncinate fasciculus, and PCA with posterior thalamic radiations, superior longitudinal fasciculus, posterior cingulate, and splenium of the corpus callosum. Conclusion: These findings show that while each AD phenotype is associated with degeneration of a specific structural network of white matter tracts, striking spatial overlap exists among the three network patterns that may be related to AD pathology.

Background and purpose A subset of patients with Alzheimer's disease ( AD ) present with early and prominent language impairment (aphasic AD ). Our previous study demonstrated an association between global β‐amyloid burden measured on [ 11 C] Pittsburgh compound B (PiB) positron emission tomography and general cognitive impairment, but not with aphasia, in such subjects. As a follow‐up, whether there is any association between regional β‐amyloid burden, atrophy on magnetic resonance imaging ( MRI ) and global cognitive impairment, aphasia or other cognitive and functional impairment in aphasic AD is assessed. Methods Forty‐four aphasic AD subjects who underwent PiB scanning and volumetric MRI and were determined to be positive for β‐amyloid deposition were analyzed. All had completed detailed neurological, neuropsychological and language batteries. Spearman's rank‐order correlation was utilized to assess for associations. Results Greater visuospatial impairment was associated with increased β‐amyloid burden in the primary visual cortex ( P = 0.001). Although there were many trends for associations between neurocognitive and language deficits and regional β‐amyloid burden, there were no strong associations that survived correction for multiple comparisons. However, neurocognitive and language impairment in these subjects strongly correlated with the degree of left lateral temporal and inferior parietal atrophy ( P < 0.004). Conclusions The findings from this study suggest a close relation between the severity of regional atrophy and cognitive and language impairment, but argue against a strong association between regional β‐amyloid burden and such deficits in aphasic AD subjects. Hence, other pathological factors may be driving the previously identified association between global β‐amyloid deposition and general cognitive impairment in aphasic AD .

Objectives The aim was for the appointed committee of the Academy of Neurological Communication Disorders and Sciences to conduct a systematic review of published intervention studies of acquired apraxia of speech (AOS), updating the previous committee's review article from 2006. Method A systematic search of 11 databases identified 215 articles, with 26 meeting inclusion criteria of (a) stating intention to measure effects of treatment on AOS and (b) data representing treatment effects for at least 1 individual stated to have AOS. Results All studies involved within-participant experimental designs, with sample sizes of 1 to 44 (median = 1). Confidence in diagnosis was rated high to reasonable in 18 of 26 studies. Most studies (24/26) reported on articulatory–kinematic approaches; 2 applied rhythm/rate control methods. Six studies had sufficient experimental control for Class III rating according to the Clinical Practice Guidelines Process Manual (American Academy of Neurology, 2011), with 15 others satisfying all criteria for Class III except use of independent or objective outcome measurement. Conclusions The most important global clinical conclusion from this review is that the weight of evidence supports a strong effect for both articulatory–kinematic and rate/rhythm approaches to AOS treatment. The quantity of work, experimental rigor, and reporting of diagnostic criteria continue to improve and strengthen confidence in the corpus of research.

Purpose This study summarizes 2 illustrative cases of a neurodegenerative speech disorder, primary progressive apraxia of speech (AOS), as a vehicle for providing an overview of the disorder and an approach to describing and quantifying its perceptual features and some of its temporal acoustic attributes. Method Two individuals with primary progressive AOS underwent speech-language and neurologic evaluations on 2 occasions, ranging from 2.0 to 7.5 years postonset. Performance on several tests, tasks, and rating scales, as well as several acoustic measures, were compared over time within and between cases. Acoustic measures were compared with performance of control speakers. Results Both patients initially presented with AOS as the only or predominant sign of disease and without aphasia or dysarthria. The presenting features and temporal progression were captured in an AOS Rating Scale, an Articulation Error Score, and temporal acoustic measures of utterance duration, syllable rates per second, rates of speechlike alternating motion and sequential motion, and a pairwise variability index measure. Conclusions AOS can be the predominant manifestation of neurodegenerative disease. Clinical ratings of its attributes and acoustic measures of some of its temporal characteristics can support its diagnosis and help quantify its salient characteristics and progression over time.