Abstract:
The aims of the study are to: (1) explore further the short- and long-term flexibility in normal speech kinematics, and (2) identify relatively stable temporal characteristics that could function as appropriate experimental and control group comparative parameters. Movements of the tongue, lips, and jaw were transduced by electromagnetic midsagittal articulography. A single session included 20 perceptually fluent repetitions of /pap/, /tat/, and /sas/ imbedded in a carrier phrase at normal, slow, and fast speech rates. Seven stutterers and matched controls completed three sessions at 2-week intervals. Reported here are across session comparisons of temporal ordering and relative timing for bilabial closure at normal rates. The prevalence and stability of the sequence pattern is dependent upon interarticulator relative time. Four control subjects and two stutterers showed idiosyncratic but stable temporal organizational characteristics within and across sessions. However, three of the controls and five of the stutterers were inconsistent in at least one of the two temporal parameters across sessions. Thus neither temporal ordering nor interarticulator relative time is an appropriate group comparative parameter because of natural long-term flexibility. Natural flexibility is compatible with the notion of coordinative structures within a task-dynamic point of view.