***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: We identified six randomised controlled trials including a total of 262 participants. Four studies were conducted with primary school or kindergarten teachers, one with student teachers and one with telemarketers. Three studies found similar self-reported vocal symptoms between those who attended direct voice training and those who were in a no intervention control group (standardised mean difference (SMD) 0.27; 95% CI -0.12 to 0.66). Two studies found similar self-reported vocal symptoms between those who attended indirect voice training and those who were in a no intervention control group (SMD 0.44; 95% CI -0.03 to 0.92). One study found similar scores on the Voice Handicap Index for those who had direct and indirect voice training combined and for those who had no intervention. Two studies compared a combination of direct and indirect voice training with indirect voice training only. Both studies found similar scores for self-reported phonation difficulty (mean difference -5.55; 95% CI -23.75 to 12.66) in both groups. The evidence for all comparisons was rated as low quality. No work-directed studies were found. No studies evaluated the effectiveness of prevention in terms of sick leave or number of diagnosed voice disorders. We found no evidence that either direct or indirect voice training or the two combined are effective in improving self-reported vocal functioning when compared to no intervention. The current practice of giving training to at-risk populations for preventing the development of voice disorders is therefore not supported by definitive evidence of effectiveness. Larger and methodologically better trials are needed with outcome measures that better reflect the aims of interventions.
Output:

We conducted a systematic search of the literature on preventing voice disorders in adults. We then appraised the quality of the studies found and combined their results. We found six studies which met our inclusion criteria. Four were conducted with teachers, one with student teachers and one with telemarketers. We found no evidence that either direct or indirect voice training nor the two combined are effective in improving vocal functioning when measured using self-reported outcomes and when compared to no intervention. All the included studies were small and of low methodological quality. Given the extent of the problem and the widespread use of voice training, further research is warranted.