A comparison of recordings of sentences and spontaneous speech: perceptual and acoustic measures in preschool children's voices.

A well-controlled recording in a studio is fundamental in most voice rehabilitation. However, this laboratory like recording method has been questioned because voice use in a natural environment may be quite different. In children's natural environment, high background noise levels are common and are an important factor contributing to voice problems. The primary noise source in day-care centers is the children themselves. The aim of the present study was to compare perceptual evaluations of voice quality and acoustic measures from a controlled recording with recordings of spontaneous speech in children's natural environment in a day-care setting. Eleven 5-year-old children were recorded three times during a day at the day care. The controlled speech material consisted of repeated sentences. Matching sentences were selected from the spontaneous speech. All sentences were repeated three times. Recordings were randomized and analyzed acoustically and perceptually. Statistic analyses showed that fundamental frequency was significantly higher in spontaneous speech (P<0.01) as was hyperfunction (P<0.001). The only characteristic the controlled sentences shared with spontaneous speech was degree of hoarseness (Spearman's rho=0.564). When data for boys and girls were analyzed separately, a correlation was found for the parameter breathiness (rho=0.551) for boys, and for girls the correlation for hoarseness remained (rho=0.752). Regarding acoustic data, none of the measures correlated across recording conditions for the whole group.