Congologlu 2009.

Methods	A cohort study of voice recordings before and after methylphenidate use
Participants	Number of patients screened: not stated Number included: 22 Number followed up: 22 Number of withdrawals: not stated Diagnosis of ADHD: DSM‐IV (subtype: combined 100%) Age: mean 9.05 (SD 1.43) years (range 7‐12) IQ: not stated Sex: 22 males Methylpenidate‐naïve: none Ethnicity: Turkish Country: Turkey Comorbidity: no Comedication: none Sociodemographics: not stated Inclusion criteria: Boys aged 7‐12 years (prepubertal) ≥ 1 year of methylphenidate use and drug‐responsive No history of specific speech and language impairments and voice‐related disorders No history of other psychiatric disorders (conduct disorder, any anxiety disorder, depressive disorder, learning disorder etc.) except oppositional defiant disorder No mental retardation, neurological disorders, sensorimotor handicaps, and chronic medical illness (respiratory diseases etc.) Exclusion criteria: Those who took medication other than methylphenidate before and at the time of recording were excluded At the time of recording, none of the participants had cold, allergy, or flu symptoms
Interventions	Methylphenidate type: not stated Methylphenidate dosage: 0.5 mg/kg 1 hour before recording voice sample Mean MPH dosage: not stated Duration of intervention: single voice measurement after single dose of methylphenidate Treatment compliance: not stated
Outcomes	Non‐serious adverse events: Speech samples using Multi Dimensional Voice Program (MDVP) Model 5105 Version 2.3 of the Computerized Speech, developed by Kay Elemetrics Speech recordings for acoustic analysis were made from the participants in 2 sessions held before noon: no‐medication baseline session and the medication session after methylphenidate administration of 0.5 mg/kg (approximately 60 minutes later) We have not used these data
Notes	Ethics approval: the study was approved by the Human Subject Review Committee at the Gülhane Military Medical Academy Funding/vested interest/authors' affiliations: not stated Any withdrawals due to adverse events: no Key conclusions of the study authors: this clinical trial is the only study that examined the effects of stimulant medication on vocal acoustic parameters in children with ADHD and evaluated a small sample on and off their clinical doses of methylphenidate. We suggest that methylphenidate decreases fundamental frequency in children with ADHD, but our findings should be replicated under blind drug administration and by supporting other vocal analyses Exclusion of methylphenidate non‐responders/children who have previously experienced adverse events on methylphenidate: no