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Objective To correlate, RSI with SVHI, in a group of singing students, by means of a specific anamnestic questionnaire which analyzes the physical, social, emotional, and economic impacts of voice problems on their lives. This study is a cross-sectional single-center observational study. Methods Forty-two modern singing students (26F/16M; average age: 24.9 ± 5.7; range: 16-46 years old) were recruited. A self-assessment of the singing-voice (SVHI) and of reflux symptom (RSI) was performed. Results Using the validated RSI threshold, 31% of participants were classified as RSI greater than 13 as an indication of suspected LPR. Classifying the SVHI score as proposed in the recent literature (cutoff of 20.35) our sample was a voice disorders prevalence of 71.4%. There was no significant positive or negative relationship between RSI and SVHI total score (rho = 0.238, P = 0.13). Instead, by considering the relationship between the individual items of the two questionnaires, it is highlighted that the item 1 of SVHI was significantly correlated with most of the RSI items ( P = 0.0001-0.006). In the same vein, the item 5 of SVHI was correlated to hoarseness and coughing ( P = 0.005-0.006). The item 20 of SVHI was significantly correlated with hoarseness, excess mucus in the throat or postnasal drip and with the pharyngeal Globus sensation ( P = 0.001-0.005). By aggregating the SVHI item response as a positive response (2-4) versus a negative response (0 or 1) between "RSI pathology classification," a significant association was observed for SVHI item 1 ( P < 0.021), item 5 ( P < 0.006), item 20 ( P < 0.042), item 24 ( P < 0.044) item 25 ( P < 0.047). These associations were confirmed by univariate binary logistic. Multivariate binary logistic regression confirms that SVHI Item 1, Item 5 were more associated with RSI positive. Based on results, we propose a questionnaire that combines the most relevant SVHI items correlated to LPRD (SVHI-10-LPRD questionnaire). Cronbach's alpha coefficient for the 10 items selected was 0.87; item-total correlation coefficients for each item were in the range of 0.461 to 0.670. Conclusions This pilot study shows that, in case of significant RSI for LPR, it is possible to observe a significant association with some symptoms described in SVHI. These results underline that the association of the RSI and SVHI questionnaires administered to singers and singing students, can represent a simple screening to reveal possible alterations of the singing voice correlate to LPR. Moreover, we propose a Singing Voice Handicap Index correlated to LPR (SVHI-10-LPRD). It will be necessary to increase the sample of subjects in the study to confirm these preliminary data.

In humans, the asymmetry in the masseter electromyographic (EMG) activity during clenching is positively correlated with the degree of pupil size asymmetry (anisocoria) at rest. Anisocoria reveals an asymmetry in LC activity, which may lead to an imbalance in cortical excitability, detrimental to performance. Hereby, we investigated, in individual subjects, the possibility that occlusal correction, which decreases EMG asymmetry, improves performance by balancing LC activity. Cognitive performance, task-related mydriasis, and pupil size at rest were modified by changing the occlusal condition. Occlusal-related changes in performance and mydriasis were negatively correlated with anisocoria changes in only 12/20 subjects. Within this population, spontaneous fluctuations in mydriasis and anisocoria also appeared negatively coupled. Occlusal-related changes in performance and mydriasis were negatively correlated with those in average pupil size (a proxy of average LC activity) in 19/20 subjects. The strongest association was observed for the pupil changes occurring on the side with higher EMG activity during clenching. These findings indicate that the effects of occlusal conditions on cognitive performance were coupled to changes in the asymmetry of LC activity in about half of the subjects, while they were related to changes in the average tonic LC activity in virtually all of them.