Temporal Structure in the Speech of Persons with Dementia: A Preliminary Study
Linda Carozza and Fredericka Bell-Berti, St. John’s College of Liberal Arts and Sciences, Department of Communication Sciences and Disorders
Abstract: The question addressed in this study is whether motor speech dysfunction occurs earlier in the dementing process than previously described, and if so, to what extent is it present in the mild disease stages?
This study explores vowel duration in two contexts - segmental phonetic environment and phrase position (phrase final lengthening), as well as voice onset time (VOT). Vowel duration variations (see, e.g. Baum & Boyczuk, 1999; Krivokapic & lee, 2006; Klatt 1976; Oller 1972l Smith, Masonic & Preston,1987; Watson & Hughes, (2006), and VOT (Lisker & Abramson, 1964; 1967) have been described in healthy speakers. Several studies have explored changes in vowel duration patterns in speakers with neurological disorders (e.g., Baum & Boyczuk, 1999; Baum, Pell Leonard & Gordon, 1997; Bell-Berti & Chevrie-Muller, 1991; Casper, Raphael, Harris & Geibel, 2007; Danly & Shapiro, 1982; Rogers, 1997; Wang, Kent, Duffy & Thomas, 2005). There is, however, no literature on how-or if-dementing illness affects these temporal patterns.
We hope that the results of this project will shed light on the presence or absence of an early motor speech deficit in dementia. Though at this point it would be entirely speculative to propose an underlying mechanism, for the purposes of the present work, we will consider these results within the theoretical framework of neural substarte specialization (Tervaniemi et. Al., 2006; Booth e. al., 2003; Tremblay and Kraus, 2002).