Academic journal article The Spanish Journal of Psychology

Acoustic Markers Associated with Impairment in Language Processing in Alzheimer's Disease

Academic journal article The Spanish Journal of Psychology

Acoustic Markers Associated with Impairment in Language Processing in Alzheimer's Disease

Article excerpt

This study broaches in a novel way the analysis of cognitive impairment characteristic of the early stages of Alzheimer's Disease (AD). Specifically, we attempt to determine the acoustic speech parameters that are sensitive to the onset of the disease, and their association with the language deficit characteristic of AD. Speech analysis was carried out on 21 elderly patients with AD using Praat software, which analyzes the acoustic components of speech. The data obtained were subjected to stepwise regression, using the overall scores obtained in the test as the criterion variable, and the scores on the frequency, amplitude and periodicity variables as predictors of performance. We found that the percentage of voiceless segments explains a significant portion of the variance in the overall scores obtained in the neuropsychological test. This component seems to be related mainly to the patient's ability in phonological fluency. This finding could permit the creation of a diagnostic test for AD through analysis of the acoustic speech parameters at very low cost in terms of both time and resources.

Keywords: Alzheimer, phonology, speech, verbal fluency.

El estudio aborda una manera novedosa el análisis de los deterioros cognitivos característicos de las primeras fases de la Enfermedad de Alzheimer (EA). En concreto, se pretende determinar los parámetros acústicos del habla sensibles al inicio de la enfermedad, y su asociación con el déficit lingüístico característico de la EA. Realizamos un análisis del habla a 21 mayores con EA, por medio del software Praat que analiza los componentes acústicos del habla. Los datos obtenidos se analizaron mediante la técnica de regresión paso a paso, con las puntuaciones globales obtenidas en las diferentes pruebas neuropsicológicas como variable criterio, (entre otras el test de Cuetos-Vega de procesamiento lingüístico) y las puntuaciones en las variables de frecuencia, amplitud y periodicidad del sonido como predictores de su ejecución. Obtuvimos que el porcentaje de segmentos sordos explica una parte significativa de la varianza de la puntuación global obtenida en la prueba neuropsicológica. Este componente parece estar relacionado, principalmente, con la capacidad de fluidez fonológica del paciente. Esto podría permitir la elaboración de una prueba de diagnóstico de la EA a través del análisis de los parámetros acústicos del habla con un coste temporal y material muy bajo.

Palabras clave: Alzheimer, fonología, alocución, fluided verbal.

Early detection of AD is determined by the predictive ability of the variables used in the making of diagnostic tests (Ferri et al., 2005). These variables have usually been defined based on preclinical symptomatology related to semantic memory and verbal fluency tasks (Pérez-Martínez, Baztán, González-Becerra, & Socorro, 2005). Both of these cognitive variables are very sensitive to the impairment observed in the early stages of AD (Cuetos-Vega, Menéndez-González, & Calatayud-Noruega, 2007; Peraita, Galeote, & González, 1999), a sensitivity that is reflected in the high demand for consultations motivated by problems involving word forgetting and language fluency in elderly individuals. For this reason, attempts have been made recently to design tests that are quick and easy to apply for screening AD and are considered reliable and valid according to neuropsychological examination. A recent article presents a test that fulfills these criteria. The test by Cuetos-Vega et al. (2007; hereafter CVT), allows us to discriminate patients with AD from individuals with Mild Cognitive Impairment (MCI) and healthy individuals, with a high degree of sensitivity and specificity. This is especially important given the well known difficulty involved in differentiating patients with AD from persons with MCI using only episodic memory tests -which can only differentiate the degree and significance of episodic memory impairment in patients with AD- (Valls-Pedret, Molinuevo, & Rami, 2010). …

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