Halama 1988.

Study characteristics
Methods	A 2‐armed (Gingko biloba and placebo), parallel‐group randomised controlled trial with 12 weeks duration of treatment and 4, 12 and 14 weeks duration of follow‐up
Participants	Location: Hamburg, Germany Setting: outpatients in the neurology practice Sample size: Number randomised: 20 in Ginkgo biloba group and 20 in placebo group Number completed: 20 in Ginkgo biloba group and 20 in placebo group Participant baseline characteristics: Age (mean (SD) years): 65.2 (6.96) in Gingko biloba group versus 66.6 (9.43) in placebo group Gender (male/female, n): not reported. Unequal gender composition of the treatment groups was mentioned in the manuscript. Other characteristics: baseline data regarding tinnitus severity, characteristics, hearing loss, depression and anxiety were not reported in the manuscript. All patients had "mild cerebral insufficiency of vascular origin". Inclusion criteria: outpatients over 55 years of age from a neurology practice with diagnosis of "mild to mass cerebral insufficiency of vascular origin", the diagnosis was based on the clinical findings and the results of the psychometric tests performed and scale ratings (Hachinski: > 7, Crichton: levels 1 to 3). Exclusion criteria: patients with psychoses or neuroses, with primary degenerative dementia, with secondary brain impairment (treatable underlying disease, e.g. intoxication, metabolic disorder, alcoholism, etc.), epilepsy or other serious illnesses (e.g. myocardial infarction in the last 6 months, severe kidney failure, severe, life‐threatening) were excluded cardiac arrhythmias, malignancy) and those who were not sufficiently capable of co‐operating. In addition, clonidine, reserpine, antihistamines, anti‐Parkinson drugs, anticoagulants, platelet aggregation inhibitors, psychotropic drugs, centrally acting stimulants or drugs that influence the hormone metabolism or blood flow were not allowed to be taken.
Interventions	Intervention group: Gingko biloba extract (Tebonin forte film tablets) 3 x 1 per day, corresponding to a daily dose of 120 mg Gingko biloba extract for 12 weeks Comparator group: placebo tablets, 3 x 1 per day for 12 weeks Use of additional interventions: none reported
Outcomes	Primary outcomes: Sandoz Clinical Assessment Geriatric (SCAG) scale at 12 weeks Secondary outcomes: Crichton scale (CRBRS), background interference method (HIV), short syndrome test (SKT), craniocorpography (CCG). The severity of dizziness symptoms, noises in the ears, headaches and reduced hormones was assessed with the help of a 4‐point rating scale at 12 weeks.
Funding sources	Not reported
Declarations of interest	Not reported
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Intervention or placebo randomly assigned by computer program to participant enrolment numbers.
Allocation concealment (selection bias)	Unclear risk	Information not provided in the manuscript.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Neither the patient nor the examining physician knew the assignment; the code was only opened after the data collection had been completed at the beginning of the evaluation. Identical tablets.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Neither the patient nor the examining physician knew this assignment; the code was only opened after the data collection had been completed at the beginning of the evaluation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All patients who were randomised were assessed.
Selective reporting (reporting bias)	High risk	Data for the majority of secondary outcome measures were not reported.
Other bias	High risk	This was a trial with patients with "mild cerebral insufficiency of vascular origin"; tinnitus was a secondary outcome measure. No prospective protocol available. No funding sources and declarations of interest reported.