ARTICULATORY DISORDERS IN PRIMARY PROGRESSIVE APHASIA - AN ACOUSTIC AND KINEMATIC ANALYSIS

Articulatory performance was investigated in a patient suffering from nonfluent primary progressive aphasia (PPA) characterized, among other factors, by apraxia of speech. Normal speakers and three subjects wit h spastic dysarthria due to pseudobulbar palsy served as controls. In addition to the acoustic signal, lower lip trajectories were recorded by means of an optoelectronic system during production of test sentenc es comprising either the sequence /pa:p/ (long vowel) or /pap/(short v owel). Normal speakers and pseudobulbar patients produced a clear-cut durational distinction between short and long vocalic targets at the a coustic and perceptual level. As compared to the short vowels, the lon g cognates were characterized by lengthened lower lip opening and clos ing gestures. In contrast, the PPA patient showed an impaired duration al contrast of the vowels /a/ and /a:/. Furthermore, this subject prod uced, unexpectedly, a similar temporal distinction of the opening, ges ture, as did the controls, but not of the closing movement. Prevailing concepts on apraxia of speech suggest impaired temporal coordination of independent articulators, whereas single gestures are considered to be largely unimpaired. Contrary to these assumptions, the present stu dy revealed that the durational adjustment of specific orofacial movem ents during speech might also be disrupted.