Functional near-infrared spectroscopy for speech protocols: characterization of motion artifacts and guidelines for improving data analysis.

Monitoring speech tasks with functional near-infrared spectroscopy (fNIRS) enables investigation of speech production mechanisms and informs treatment strategies for speech-related disorders such as stuttering. Unfortunately, due to movement of the temporalis muscle, speech production can induce relative movement between probe optodes and skin. These movements generate motion artifacts during speech tasks. In practice, spurious hemodynamic responses in functional activation signals arise from lack of information about the consequences of speech-related motion artifacts, as well as from lack of standardized processing procedures for fNIRS signals during speech tasks. To this end, we characterize the effects of speech production on fNIRS signals, and we introduce a systematic analysis to ameliorate motion artifacts. The study measured 50 healthy subjects performing jaw movement (JM) tasks and found that JM produces two different patterns of motion artifacts in fNIRS. To remove these unwanted contributions, we validate a hybrid motion-correction algorithm based sequentially on spline interpolation and then wavelet filtering. We compared performance of the hybrid algorithm with standard algorithms based on spline interpolation only and wavelet decomposition only. The hybrid algorithm corrected 94% of the artifacts produced by JM, and it did not lead to spurious responses in the data. We also validated the hybrid algorithm during a reading task performed under two different conditions: reading aloud and reading silently. For both conditions, we observed significant cortical activation in brain regions related to reading. Moreover, when comparing the two conditions, good agreement of spatial and temporal activation patterns was found only when data were analyzed using the hybrid approach. Overall, the study demonstrates a standardized processing scheme for fNIRS data during speech protocols. The scheme decreases spurious responses and intersubject variability due to motion artifacts.

Measuring role entrapment of people who stutter.

UNLABELLED: The purpose of this study was to explore whether people who stutter experience role entrapment in the form of vocational stereotyping. To accomplish this, 385 university students reported their perceptions of appropriate career choices for people who stutter. Direct survey procedures, utilizing the newly developed Vocational Advice Scale (VAS), were used in this study. Comparisons for the main effect of speaker status (person who stutters and person who does not stutter) were conducted using a one-way analysis of variance (ANOVA). Results of this analysis suggested that the university students reported an overall perception that stuttering affected career opportunities and that 20 careers were judged to be inappropriate choices for people who stutter. Conversely, 23 careers were judged to be appropriate choices for people who stutter. Findings of this study provide initial data that supports that people who stutter may suffer from role entrapment related to career choices. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) provide the definitions of stereotyping, role entrapment, and how these relate to people who stutter; (2) discuss the career choices that college students perceive as appropriate and inappropriate for people who stutter; and (3) summarize the needs for future research in this area.

A preliminary study of self-esteem, stigma, and disclosure in adolescents who stutter.

UNLABELLED: This study examined the self-esteem, perceived stigma, and disclosure practices of 48 adolescents who stutter divided into two age cohorts: younger (13, 14, and 15 years) and older (16, 17, and 18 years) adolescents. Results revealed that 41 (85%) of the participants scored within 1 S.D. from the mean on a standardized measure of self-esteem, indicative of positive self-esteem. Results also showed that stuttering did not present a stigmatizing condition for the majority (65%) of adolescents who stutter. However, 60% of participants indicated that they "rarely" or "never" discussed their stuttering. The younger adolescents perceived stuttering as a more negative and stigmatizing condition than older adolescents. Implications for understanding stuttering in adolescents are discussed. EDUCATIONAL OBJECTIVES: Readers will learn about and understand (a) the role of stigma, disclosure, and self-esteem in stuttering; (b) the methods used to evaluate stigma, disclosure, and self-esteem in adolescents; and (c) the similarities between adolescents who stutter and normative data on self-esteem and stigma scales.