Increase of precuneus metabolism correlates with reduction of PTSD symptoms after EMDR therapy in military veterans: an 18F-FDG PET study during virtual reality exposure to war

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Détection des occlusives à l'aide de la transformée en ondelettes

This paper describes the detection of stop consonants in the French language with the help of the wavelet transform. Our hypothesis is that the burst of stop consonants can be approximated with a pulse. The detection system is based on the study of the correlation functions between the modulus of the impulse wavelet transform and the same transform of the speech signal. As we are using a Gaussian wavelet, the correlation functions have a minimum before each maximum, where that maximum is synchronous with the burst of the stop consonant. Two signals SM and Sm are computed. They are respectively the synchronous and asynchronous sums of all the correlation functions. To localize the local minima of the Sm function, two criteria are used. The temporal localisation of the pulse is accomplished with certain local maxima of the signal SM. The method of detection is tested with a corpus which has 137 unvoiced and 55 voiced stop consonants. The rate of detection is 94% for the unvoiced stops and 75% for the voiced stops. This study shows that for detection, the burst of stop consonants can be modelled with a pulse

Involvement of the cerebellum in EMDR efficiency: a metabolic connectivity PET study in PTSD

International audienceBackgroundWe recently reported an improvement of precuneus PET metabolism after EMDR therapy in military participants suffering from PTSD.ObjectiveThe aim of the present study was to investigate the metabolic changes of precuneus connectivity in these participants after such treatment.MethodFifteen participants with PTSD performed a brain 18F-FDG-PET sensitized by virtual reality exposure to war scenes, before and after EMDR treatment. Inter-regional correlation analysis was performed to study metabolic changes of precuneus connectivity through SPMT maps at whole-brain level (p < 0.005 for the voxel, p < 0.05 for the cluster).ResultsA decrease of connectivity was observed after EMDR between the precuneus and two significant bilateral clusters of the cerebellum (bilateral Crus I and VI cerebellar lobules, Tmax voxel of 5.8 and 5.3, and cluster size of 343 and 314 voxels, respectively). Moreover, higher cerebellar metabolism before treatment was associated with reduced clinical PTSD scores after EMDR (p = 0.03).ConclusionsThe posterior cerebellum and its metabolic connectivity with the precuneus are involved in the clinical efficiency of EMDR in PTSD