Apraxia in progressive nonfluent aphasia

The clinical and neuroanatomical correlates of specific apraxias in neurodegenerative disease are not well understood. Here we addressed this issue in progressive nonfluent aphasia (PNFA), a canonical subtype of frontotemporal lobar degeneration that has been consistently associated with apraxia of speech (AOS) and in some cases orofacial apraxia, limb apraxia and/or parkinsonism. Sixteen patients with PNFA according to current consensus criteria were studied. Three patients had a corticobasal syndrome (CBS) and two a progressive supranuclear palsy (PSP) syndrome. Speech, orofacial and limb praxis functions were assessed using the Apraxia Battery for Adults-2 and a voxel-based morphometry (VBM) analysis was conducted on brain MRI scans from the patient cohort in order to identify neuroanatomical correlates. All patients had AOS based on reduced diadochokinetic rate, 69% of cases had an abnormal orofacial apraxia score and 44% of cases (including the three CBS cases and one case with PSP) had an abnormal limb apraxia score. Severity of orofacial apraxia (but not AOS or limb apraxia) correlated with estimated clinical disease duration. The VBM analysis identified distinct neuroanatomical bases for each form of apraxia: the severity of AOS correlated with left posterior inferior frontal lobe atrophy; orofacial apraxia with left middle frontal, premotor and supplementary motor cortical atrophy; and limb apraxia with left inferior parietal lobe atrophy. Our findings show that apraxia of various kinds can be a clinical issue in PNFA and demonstrate that specific apraxias are clinically and anatomically dissociable within this population of patients

Low-frequency vocal modulations in vowels produced by parkinsonian subjects

Low-frequency vocal modulations here designate slow disturbances of the phonatory frequency F0. They are present in all voiced speech sounds, but their properties may be affected by neurological disease. An analysis method, based on continuous wavelet transforms, is proposed to extract the phonatory frequency trace and low-frequency vocal modulation in sustained speech sounds. The method is used to analyze a corpus of vowels uttered by male and female speakers, some of whom are healthy and some of whom suffer from Parkinson's disease. The latter present general speech problems but their voice is not perceived as tremulous. The objective is to discover differences between speaker groups in F0 low-frequency modulations. Results show that Parkinson's disease has different effects on the voice of male and female speakers. The average phonatory frequency is significantly higher for male Parkinsonian speakers. The modulation amplitude is significantly higher for female Parkinsonian speakers. The modulation frequency is significantly higher and the ratio between the modulation energies in the frequency bands [3 Hz, 7 Hz] and [7 Hz, 15 Hz] is significantly lower for Parkinsonian speakers of both genders. © 2007 Elsevier B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Etude de l’expression génique dans la maladie de Parkinson

International audienc

Genes de l’autophagie : marqueurs sanguins potentiels de la maladie de Parkinson

International audienc