Speech production in people who stutter: Testing the motor plan assembly hypothesis

Contains fulltext : 23009___.PDF (publisher's version ) (Open Access)The main purpose of the present study was to test the hypothesis that persons who stutter, when compared to persons who do not stutter, are less able to assemble abstract motor plans for short verbal responses. Subjects were adult males who stutter and age- and sex-matched control speakers, who were tested on naming pictures and words, using a choice-reaction time paradigm for both tasks. Words varied in the number of syllables (1, 2, and 3 syllables) and, for the bisyllabic words, also in the number of consonants (one or more) at the onset of the second syllable. Measurements consisted of speech reaction times, word durations, and measures of relative timing of specific motor events in the respiratory, phonatory, and articulatory subsystems. Results indicated that, in spite of longer speech reaction times for persons who stutter in comparison to control speakers, there was no interaction with word size, a finding that does not lend support to the abovementioned hypothesis. Word durations were found to be longer for persons who stutter, and, in addition, there was an interaction of group with word size. Both findings were associated with longer delays for persons who stutter in the onset of upper lip integrated electromyographic (IEMG) activity and thoracic compression, and a group effect on the order of upper lip and lower lip IEMG onset. Findings are taken to suggest the possibility that persons who stutter may use different motor control strategies to compensate for a reduced verbal motor skill, and although the nature of this reduced skill is unknown, it is speculated that it relates to the processes involved in the integration of sensory-motor information

From planning to articulation in speech production: What differentiates a person who stutters from a person who does not stutter?

Contains fulltext : 23922___.PDF (publisher's version ) (Open Access)The main purpose of the present study was to differentiate between people who stutter and control speakers regarding their ability to assemble motor plans and to prepare (and execute) muscle commands. Adult males who stutter, matched for age, gender, and educational level with a group of control speakers, were tested on naming words and symbols. In addition, their ability to encode and retrieve memory representations of combinations of a symbol and a word, was tested in a recognition task, using manual reaction times and sensitivity scores, as defined in signal detection theory, as performance measures. Group differences in muscle command preparation were assessed from electromyographic recordings of upper lip and lower lip. Results indicated no interaction between group and word size effects in choice reaction times or a group effect in the ability to recognize previously learned symbol-word combinations. However, they were significantly different in the timing of peak amplitudes in the integrated electromyographic signals of upper lip and lower lip (IEMG peak latency). Findings question the claim that people who stutter have problems in creating abstract motor plans for speech. n addition, it is argued that the group differences in IEMG peak latency that were found in the present study might be better understood in terms of motor control strategies than in terms of motor control deficits

Correlates and outcomes of alcohol use after single solid organ transplantation: A systematic review and meta-analysis.

Abstract BACKGROUND: Reviews on alcohol use in transplant recipients focus on liver recipients and their risk of post-transplant rejection, but do not assess alcohol use in kidney, heart, or lung transplant recipients. This systematic review and meta-analysis aims to synthesize the evidence on correlates and outcomes of any alcohol use and at-risk drinking after solid organ transplantation (Tx). METHODS: We searched 4 databases for quantitative studies in adult heart, liver, kidney and lung Tx recipients, investigating associations between post-Tx alcohol use and correlates and/or clinical, economic or quality of life outcomes. Paper selection, data extraction and quality assessment were performed by 2 reviewers independently. A pooled odds ratio (OR) was computed for each correlate/outcome reported ≥5 times. RESULTS: Of the 5331 studies identified, 76 were included in this systematic review (93.3% on liver Tx; mean sample size 148.9 (SD = 160.2); 71.9% male; mean age 48.9 years (SD = 6.5); mean time post-Tx 57.7 months (SD = 23.1)). On average, 23.6% of patients studied used alcohol post-transplant. Ninety-three correlates of any post-Tx alcohol use were identified, and 9 of the 19 pooled ORs were significantly associated with a higher odds for any post-Tx alcohol use: male gender, being employed post-transplant, smoking pre-transplant, smoking post-transplant, a history of illicit drug use, having first-degree relatives who have alcohol-related problems, sobriety <6 months prior to transplant, a history of psychiatric illness, and having received treatment for alcohol-related problems pre-transplant. On average 15.1% of patients had at-risk drinking. A pooled OR was calculated for 6 of the 47 correlates of post-Tx at risk drinking investigated, of which pre-transplant smoking was the only correlate being significantly associated with this behavior. None of the outcomes investigated were significantly associated with any use or at-risk drinking. CONCLUSION: Correlates of alcohol use remain under-investigated in solid organ transplant recipients other than liver transplantation. Further research is needed to determine whether any alcohol use or at-risk drinking is associated with poorer post-transplant outcomes. Our meta-analysis highlights avenues for future research of higher methodological quality and improved clinical care. PROTOCOL REGISTRATION: PROSPERO protocol CRD42015003333