38 research outputs found
Logopenic and nonfluent variants of primary progressive aphasia are differentiated by acoustic measures of speech production
Differentiation of logopenic (lvPPA) and nonfluent/agrammatic (nfvPPA) variants of Primary Progressive Aphasia is important yet remains challenging since it hinges on expert based evaluation of speech and language production. In this study acoustic measures of speech in conjunction with voxel-based morphometry were used to determine the success of the measures as an adjunct to diagnosis and to explore the neural basis of apraxia of speech in nfvPPA. Forty-one patients (21 lvPPA, 20 nfvPPA) were recruited from a consecutive sample with suspected frontotemporal dementia. Patients were diagnosed using the current gold-standard of expert perceptual judgment, based on presence/absence of particular speech features during speaking tasks. Seventeen healthy age-matched adults served as controls. MRI scans were available for 11 control and 37 PPA cases; 23 of the PPA cases underwent amyloid ligand PET imaging. Measures, corresponding to perceptual features of apraxia of speech, were periods of silence during reading and relative vowel duration and intensity in polysyllable word repetition. Discriminant function analyses revealed that a measure of relative vowel duration differentiated nfvPPA cases from both control and lvPPA cases (r2 = 0.47) with 88% agreement with expert judgment of presence of apraxia of speech in nfvPPA cases. VBM analysis showed that relative vowel duration covaried with grey matter intensity in areas critical for speech motor planning and programming: precentral gyrus, supplementary motor area and inferior frontal gyrus bilaterally, only affected in the nfvPPA group. This bilateral involvement of frontal speech networks in nfvPPA potentially affects access to compensatory mechanisms involving right hemisphere homologues. Measures of silences during reading also discriminated the PPA and control groups, but did not increase predictive accuracy. Findings suggest that a measure of relative vowel duration from of a polysyllable word repetition task may be sufficient for detecting most cases of apraxia of speech and distinguishing between nfvPPA and lvPPA
Patterns in German /ÊC/-cluster acquisition
This study reports on the developmental patterns of /ÊC/ clusters in 145 normally developing monolingual German-speaking children between 2;00 and 2;11. All children completed a picture naming task to allow a systematic qualitative analysis of the production patterns. Childrenâs reductions of target /ÊC/clusters are examined and are evaluated with respect to two models, âfactorial typologyâ and âheadednessâ, to account for them. The results reveal expected patterns of C2 retention for â/Ê/+[âcontinuant]â (e.g. â/Ê/+stopâ and â/Ê/+nasalâ) targets, and a rather indeterminate pattern for /Êl/ and /ÊÊ/. The results for /Êv/, a clear-cut preference of C2 retention, were rather unexpected, as the C2 is a [+continuant]. The explanation offered for the retention of /v/ is related to a place constraint. The study also examines the data from children who reached an advanced stage of cluster formation with differential targets. More specifically, in several children, one target, /Êv/, is found to have stayed behind in the reduction phase while all others have advanced to the âcluster stageâ. Neither the type nor the token frequencies seem satisfactory in accounting for the specific behaviour of /Êv/. The explanation offered for the uniqueness of this target may be its non-abidence to the Sonority Sequencing Principle (SSP) because of its flat sonority and the Obligatory Contour Principle (OCP) [continuant], because of the unchanging âcontinuanceâ which is demanded by the OCP. Theoretical and clinical implications are discussed
Klassifizierung der Sprechapraxie anhand der Spontansprache - Welche Merkmale fĂŒhren zu einer zuverlĂ€ssigen Klassifizierung?
Hintergrund: Derzeit existiert noch kein differenziertes Diagnostikverfahren, um Lautbildungsstörungen bei Sprechapraxie in der Spontansprache zu untersuchen. Die aktuelle Studie soll eine kĂŒrzlich entwickelte Methode zur Bewertung von erworbenen Lautbildungsstörungen anhand von Spontansprachproben validieren. Es wurde untersucht, ob eine Kombination aus spezifischen lautsprachlichen Merkmalen extrahiert werden kann, die auf eine Sprechapraxie hinweisen und ob dieses Ergebnis mithilfe weiterer AuĂenkriterien validiert werden kann. Die Studie verfolgt damit das Ziel, ein zuverlĂ€ssiges Instrument fĂŒr die Sprechapraxiediagnostik anhand der Spontansprache zu entwickeln.Material und Methoden: Die Spontansprachanalyse erfolgte bei 101 Aphasiepatienten nach linkshemisphĂ€rischem Schlaganfall. FĂŒr die Bewertung wurden 11 Variablen, bestehend aus segmentalen und suprasegmentalen Fehlerkategorien sowie AuffĂ€lligkeiten im Sprechverhalten, mit einer Skala ĂŒber die gesamte ĂuĂerung hinweg beurteilt. Eine Hauptkomponentenanalyse sollte eine Merkmalskombination identifizieren, um die Patienten mit Sprechapraxie innerhalb der Stichprobe festzustellen. Die Validierung erfolgte anhand von ExperteneinschĂ€tzungen und vorliegenden klinischen Daten (AAT, HWL).Ergebnisse: Die Faktorenanalyse lieferte ein 3-Faktoren-Modell, das 57,9% der Varianz erklĂ€rte. Dabei reprĂ€sentierte der erste Faktor (31,5% der Varianz) mit starken Variablen wie phonetischen Entstellungen oder reduzierter Artikulationsgeschwindigkeit Merkmale, die als Indikatoren fĂŒr Sprechapraxie anerkannt sind. Sowohl mit den Expertenratings als auch mit den HWL-Ergebnissen und Variablen des AAT zeigte sich eine hohe und signifikante Korrelation mir den Faktorwerten.Diskussion: Auf der Grundlage der bisherigen Ergebnisse stellt die hier entwickelte Analysemethode ein aussagekrĂ€ftiges Instrument zur Beurteilung der Sprechapraxie auf Spontansprachebene dar. FĂŒr eine Subgruppe von Patienten vor allem mit schweren Aphasien stellte sich heraus, dass Zusatzuntersuchungen auf Einzelwortebene (z.B. HWL) fĂŒr die Diagnostik unverzichtbar sind.Fazit: Die Ergebnisse der Analyse eines umfangreichen Datensatzes sind von groĂer klinischer Relevanz, da sie die diagnostischen Möglichkeiten fĂŒr zentrale Sprechstörungen um einen wichtigen neuen Zugang erweitern. Die Ergebnisse dieser Arbeit zeigen, dass das Störungsbild der Sprechapraxie, mit Ausnahme schwerer Formen, durch eine differenzierte Spontansprachanalyse klassifiziert werden kann
Do Patients With Neurogenic Speech Sound Impairments Benefit From Auditory Priming With a Regular Metrical Pattern?
Entraining with another person\u27s speech rhythm: Evidence from healthy speakers and individuals with Parkinson\u27s disease
Event-related Potentials Reflecting the Processing of Phonological Constraint Violations
How are violations of phonological constraints processed in word comprehension? The present article reports the results of an event-related potentials (ERP) study on a phonological constraint of German that disallows identical segments within a syllable or word (CC iVCi). We examined three types of monosyllabic CCVC words: (a) existing words ( p k), (b) wellformed novel words ( p f), and (c) illformed novel words ( p p) as instances of Obligatory Contour Principle (OCP) violations. Wellformed and illformed novel words evoked an N400 effect in comparison to existing words. In addition, illformed words produced an enhanced late posterior positivity effect compared to wellformed novel words. Our findings support the well-known observation that novel words evoke higher costs in lexical integration (reflected by N400 effects). Crucially, modulations of a late positive component (LPC) show that violations of phonotactic constraints influence later stages of cognitive processing even when stimuli have already been detected as non-existing. Thus, the comparison of electrophysiological effects evoked by the two types of non-existing words reveals the stages at which phonologically based structural wellformedness comes into play during word processing