Characteristics of fundamental laryngeal voice (f0) in developmental verbal apraxia

Objective. Developmental verbal apraxia (DVA), or developmental apraxia of speech is a motor speech disorder of motor programming and planning. Children with DVA have problems with saying sounds, syllables, and words. The aim of the study was to determine the characteristics fundamental of laryngeal voice in developmental verbal apraxia. Two parameters are observed: height and tension of voice. The research was conducted at the Institute for Experimental Phonetics and Speech Pathology and in the Institute of psychophysiological disorders and speech in Belgrade. Methods. The sample consisted of 45 children ages 4-5 years. The first group (N=15) were children with diagnosed developmental verbal apraxia, the second group (N=15) children with diagnosed developmental dysphasia, and the third group (N=15) included children with diagnosed developmental phonological disorders. Groups were equalized in relation to age. The study was carried out individually. Results. Qualitative analysis of the results showed that: for 20% of group with phonological disorders it is present low voice in the normal tension, and in 80% of children it is present normal height in a normal voice tension. In group with dysphasia 13.4% of children have a low voice in the normal tension, 66.6% of children have normal height and normal tension, and 20% of children have raised voice in a normal tension. In the group of children with developmental verbal apraxia, 26.6% of children have a low voice in the hypotension of the first degree, 6.6% of children have a low voice in normal tension, three children have low voice in hypertension of the second degree, 20% of children have elevated voice in hypotension of the second degree, 6.6% have increased voice in a normal tension, and 20% have elevated voice in the first degree of hypertension. Conclusion. Results show that disturbances in height and tension of fundamental laryngeal voice are present in children with developmental verbal apraxia in a greater degree than in children with developmental dysphasia and developmental phonological disorders.