Effects of online augmented kinematic and perceptual feedback on treatment of speech movements in apraxia of speech.

Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and temporal parameters of movement. Research on motor learning suggests that augmented feedback may provide a beneficial effect for training movement. This study examined the effects of the presence and frequency of online augmented visual kinematic feedback (AVKF) and clinician-provided perceptual feedback on speech accuracy in 2 adults with acquired AOS. Within a single-subject multiple-baseline design, AVKF was provided using electromagnetic midsagittal articulography (EMA) in 2 feedback conditions (50 or 100%). Articulator placement was specified for speech motor targets (SMTs). Treated and baselined SMTs were in the initial or final position of single-syllable words, in varying consonant-vowel or vowel-consonant contexts. SMTs were selected based on each participant's pre-assessed erred productions. Productions were digitally recorded and online perceptual judgments of accuracy (including segment and intersegment distortions) were made. Inter- and intra-judge reliability for perceptual accuracy was high. Results measured by visual inspection and effect size revealed positive acquisition and generalization effects for both participants. Generalization occurred across vowel contexts and to untreated probes. Results of the frequency manipulation were confounded by presentation order. Maintenance of learned and generalized effects were demonstrated for 1 participant. These data provide support for the role of augmented feedback in treating speech movements that result in perceptually accurate speech production. Future investigations will explore the independent contributions of each feedback type (i.e. kinematic and perceptual) in producing efficient and effective training of SMTs in persons with AOS.

Effect of narrow, pulsed high voltages on bacterial viability.

BACKGROUND AND PURPOSE: High-voltage pulsed current (HVPC) has been used to promote the healing of decubitus ulcers and surgical wounds. The benefits of HVPC are thought to include an antimicrobial action. This study was undertaken to explore the development of an in vitro system for the systematic evaluation of the effects of HVPC. METHODS: Using agarose-based media, the system allows for examination of the direct effect of HVPC on microorganisms as well as exploration of the possible in situ generation of bacteriostatic or bactericidal factors by the action of HVPC on constituents of the media. The solid media also allow characterization of the spatial extent of the current's effects such as changes in temperature or pH. The system was used to examine the effects of HVPC on four different species of bacteria: Escherichia coli, Klebsiella, Pseudomonas aeruginosa, and Staphylococcus aureus. RESULTS: Both direct and indirect bactericidal effects were observed at either the positive or negative electrode, or both, for each of the organisms, although zones of inhibition varied. Temperature and pH were examined as possible mechanisms for the indirect effect. Temperature changes observed during the application of HVPC were minimal and did not contribute to the antimicrobial effect. Extreme pH changes did not appear to be the major cause of the indirect effect because the zones of inhibition observed were generally larger than the zones of extremely acid or basic pHs. CONCLUSION AND DISCUSSION: High-voltage pulsed current produced antimicrobial effects in this in vitro study. Additional studies are needed to elucidate the mechanisms and to determine whether the mechanisms occur in vivo.