Heather M. Clark

The apraxia of speech rating scale: A tool for diagnosis and description of apraxia of speech

UNLABELLED The purpose of this report is to describe an initial version of the Apraxia of Speech Rating Scale (ASRS), a scale designed to quantify the presence or absence, relative frequency, and severity of characteristics frequently associated with apraxia of speech (AOS). In this paper we report intra-judge and inter-judge reliability, as well as indices of validity, for the ASRS which was completed for 133 adult participants with a neurodegenerative speech or language disorder, 56 of whom had AOS. The overall inter-judge ICC among three clinicians was 0.94 for the total ASRS score and 0.91 for the number of AOS characteristics identified as present. Intra-judge ICC measures were high, ranging from 0.91 to 0.98. Validity was demonstrated on the basis of strong correlations with independent clinical diagnosis, as well as strong correlations of ASRS scores with independent clinical judgments of AOS severity. Results suggest that the ASRS is a potentially useful tool for documenting the presence and severity of characteristics of AOS. At this point in its development it has good potential for broader clinical use and for better subject description in AOS research. LEARNING OUTCOMES The Apraxia of Speech Rating Scale: A new tool for diagnosis and description of apraxia of speech 1. The reader will be able to explain characteristics of apraxia of speech. 2. The reader will be able to demonstrate use of a rating scale to document the presence and severity of speech characteristics. 3. The reader will be able to explain the reliability and validity of the ASRS.

Primary progressive apraxia of speech: Clinical features and acoustic and neurologic correlates

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.

Perceptual and instrumental assessments of orofacial muscle tone in dysarthric and normal speakers

Clinical assessment of orofacial muscle tone is of interest for differential diagnosis of the dysarthrias, but standardized procedures and normative data are lacking. In this study, perceptual ratings of tone were compared with instrumental measures of tissue stiffness for facial, lingual, and masticatory muscles in 70 individuals with dysarthria. Perceptual and instrumental tone data were discordant and failed to discriminate between five dysarthria types. These results raised concerns about the validity of Myoton-3 stiffness measures in the orofacial muscles. Therefore, a second study evaluated contracted and relaxed orofacial muscles in 10 neurotypical adults. Results for the cheek, masseter, and lateral tongue surface followed predictions, with significantly higher tissue stiffness during contraction. In contradiction, stiffness measures from the superior surface of the tongue were lower during contraction. Superior-to-inferior tongue thickness was notably increased during contraction. A third study revealed that tissue thickness up to ~10 mm significantly affected Myoton-3 measures. Altered tissue thickness due to neuromuscular conditions like spasticity and atrophy may have undermined the detection of group differences in the original sample of dysarthric speakers. These experiments underscore the challenges of assessing orofacial muscle tone and identify considerations for quantification of tone-related differences across dysarthria groups in future studies.

NMDA receptor encephalitis causing reversible caudate changes on MRI and PET imaging

Since the original description of the classic phenotype of memory deficits, psychiatric symptoms, decreased consciousness, and hypoventilation was described in association with NMDAR antibodies, the phenotype of NMDAR encephalitis has expanded to include patients with a pure psychiatric presentation, insomnia, isolated dystonia, paroxysmal limb weakness, and eye movement abnormalities.1 Despite prominent dystonia and dyskinesias, reversible basal ganglia abnormalities on structural MRI and FDG-PET have not been reported to date, even in patients with isolated hemidystonia.2

Tracking the development of agrammatic aphasia: A tensor-based morphometry study

Agrammatic aphasia can be observed in neurodegenerative disorders and has been traditionally linked with damage to Brocas area, although there have been disagreements concerning whether damage to Brocas area is necessary or sufficient for the development of agrammatism. We aimed to investigate the neuroanatomical correlates of the emergence of agrammatic aphasia utilizing a unique cohort of patients with primary progressive apraxia of speech (PPAOS) that did not have agrammatism at baseline but developed agrammatic aphasia over time. Twenty PPAOS patients were recruited and underwent detailed speech/language assessments and 3T MRI at two visits, approximately two years apart. None of the patients showed evidence of agrammatism in writing or speech at baseline. Eight patients developed aphasia at follow-up (progressors) and 12 did not (non-progressors). Tensor-based morphometry utilizing symmetric normalization (SyN) was used to assess patterns of grey matter atrophy and voxel-based morphometry was used to assess patterns of grey matter loss at baseline. The progressors were younger at onset and more likely to show distorted sound substitutions or additions compared to non-progressors. Both groups showed change over time in premotor and motor cortices, posterior frontal lobe, basal ganglia, thalamus and midbrain, but the progressors showed greater rates of atrophy in left pars triangularis, thalamus and putamen compared to non-progressors. The progressors also showed greater grey matter loss in pars triangularis and putamen at baseline. This cohort provided a unique opportunity to assess the anatomical changes that accompany the development of agrammatic aphasia. The results suggest that damage to a network of regions including Brocas area, thalamus and basal ganglia are responsible for the development of agrammatic aphasia in PPAOS. Clinical and neuroimaging abnormalities were also present before the onset of agrammatism that could help improve prognosis in these subjects.

Clinical and imaging characterization of progressive spastic dysarthria

To 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.

Effects of Age, Sex, and Body Position on Orofacial Muscle Tone in Healthy Adults

PURPOSE Quantification of tissue stiffness may facilitate identification of abnormalities in orofacial muscle tone and thus contribute to differential diagnosis of dysarthria. Tissue stiffness is affected by muscle tone as well as age-related changes in muscle and connective tissue. METHOD The Myoton-3 measured tissue stiffness in 40 healthy adults, including equal numbers of men and women in each of two age groups: 18-40 years and 60+ years. Data were collected from relaxed muscles at the masseter, cheek, and lateral tongue surfaces in two positions: reclined on the side and seated with head tilted. RESULTS Tissue stiffness differed across age, sex, and measurement site with multiple interaction effects. Overall, older subjects exhibited higher stiffness coefficients and oscillation frequency measures than younger subjects whereas sex differences varied by tissue site. Effects of body position were inconsistent across tissue site and measurement. CONCLUSIONS Although older subjects were expected to have lower muscle tone, age-related nonmuscular tissue changes may have contributed to yield a net effect of higher stiffness. These data raise several considerations for the development of accurate normative data and for future diagnostic applications of tissue stiffness assessment.

[18F]AV-1451 tau-PET and primary progressive aphasia: [18F]AV-1451 and PPA

To assess [18F]AV‐1451 tau‐PET (positron emission tomography) uptake patterns across the primary progressive aphasia (PPA) variants (logopenic, semantic, and agrammatic), examine regional uptake patterns of [18F]AV‐1451 independent of clinical diagnosis, and compare the diagnostic utility of [18F]AV‐1451, [18F]‐fluorodeoxygluclose (FDG)‐PET and MRI (magnetic resonance imaging) to differentiate the PPA variants.

Prosodic and phonetic subtypes of primary progressive apraxia of speech

HighlightsPhonetic PPAOS is characterized predominantly by distorted sound substitutions.Prosodic PPAOS is characterized predominantly by slow, segmented speech.The predominant clinical characteristics of PPAOS can be quantified reliably.PPAOS subtypes are associated with distinct imaging patterns on MRI, DTI, and FDG‐PET. Abstract Primary progressive apraxia of speech (PPAOS) is a clinical syndrome in which apraxia of speech is the initial indication of neurodegenerative disease. Prior studies of PPAOS have identified hypometabolism, grey matter atrophy, and white matter tract degeneration in the frontal gyri, precentral cortex, and supplementary motor area (SMA). Recent clinical observations suggest two distinct subtypes of PPAOS may exist. Phonetic PPAOS is characterized predominantly by distorted sound substitutions. Prosodic PPAOS is characterized predominantly by slow, segmented speech. Demographic, clinical, and neuroimaging data (MRI, DTI, and FDG‐PET) were analyzed to validate these subtypes and explore anatomic correlates. The Phonetic subtype demonstrated bilateral involvement of the SMA, precentral gyrus, and cerebellar crus. The Prosodic subtype demonstrated more focal involvement in the SMA and right superior cerebellar peduncle. The findings provide converging evidence that differences in the reliably determined predominant clinical characteristics of AOS are associated with distinct imaging patterns, independent of severity.

Longitudinal structural and molecular neuroimaging in agrammatic primary progressive aphasia

The agrammatic variant of primary progressive aphasia affects normal grammatical language production, often occurs with apraxia of speech, and is associated with left frontal abnormalities on cross-sectional neuroimaging studies. We aimed to perform a detailed assessment of longitudinal change on structural and molecular neuroimaging to provide a complete picture of neurodegeneration in these patients, and to determine how patterns of progression compare to patients with isolated apraxia of speech (primary progressive apraxia of speech). We assessed longitudinal structural MRI, diffusion tensor imaging and 18F-fluorodeoxyglucose PET in 11 agrammatic aphasia subjects, 20 primary progressive apraxia of speech subjects, and 62 age and gender-matched controls with two serial assessments. Rates of change in grey matter volume and hypometabolism, and white matter fractional anisotropy, mean diffusivity, radial diffusivity and axial diffusivity were assessed at the voxel-level and for numerous regions of interest. The greatest rates of grey matter atrophy in agrammatic aphasia were observed in inferior, middle, and superior frontal gyri, premotor and motor cortices, as well as medial temporal lobe, insula, basal ganglia, and brainstem compared to controls. Longitudinal decline in metabolism was observed in the same regions, with additional findings in medial and lateral parietal lobe. Diffusion tensor imaging changes were prominent bilaterally in inferior and middle frontal white matter and superior longitudinal fasciculus, as well as right inferior fronto-occipital fasciculus, superior frontal and precentral white matter. More focal patterns of degeneration of motor and premotor cortex were observed in primary progressive apraxia of speech. Agrammatic aphasia showed greater rates of grey matter atrophy, decline in metabolism, and white matter degeneration compared to primary progressive apraxia of speech in the left frontal lobe, predominantly inferior and middle frontal grey and white matter. Correlations were also assessed between rates of change on neuroimaging and rates of clinical decline. Progression of aphasia correlated with rates of degeneration in frontal and temporal regions within the language network, while progression of parkinsonism and limb apraxia correlated with degeneration of motor cortex and brainstem. These findings demonstrate that disease progression in agrammatic aphasia is associated with widespread neurodegeneration throughout regions of the language network, as well as connecting white matter tracts, but also with progression to regions outside of the language network that are responsible for the development of motor symptoms. The fact that patterns of progression differed from primary progressive apraxia of speech supports the clinical distinction of these syndromes.