Fucci 1992.

Study characteristics
Methods	A 2‐armed (Gingko biloba and placebo), parallel‐group randomised controlled trial with 6 months duration of treatment and 3 and 6 months duration of follow‐up
Participants	Location: Philadelphia, USA Setting: Department of Otorhinolaryngology, Temple University Medical School, Philadelphia, USA Sample size: Number randomised: 40 in Ginkgo biloba and placebo group Number completed: not reported Participant baseline characteristics: Age (mean (SD) years): not reported Gender (male/female, n): not reported Other characteristics: data for baseline tinnitus severity, baseline tinnitus duration, loudness, laterality and characteristics, baseline depression and anxiety, baseline degree and characteristics of hearing loss were not provided. Inclusion criteria: participants with tinnitus Exclusion criteria: not reported
Interventions	Intervention group: Ginkgo biloba extract (EGb, bioflavonoid) for 6 months Comparator group: placebo for 6 months Use of additional interventions: none reported
Outcomes	Primary outcomes: tinnitus loudness and annoyance measured with numerical rating scales (1 to 10) at 3 and 6 months Secondary outcomes: pure tone air and bone conduction thresholds, speech discrimination scores, speech reception thresholds, impedance audiometry, tinnitus loudness matching levels, tinnitus minimum masking levels and tinnitus pitch matching frequencies at 3 and 6 months
Funding sources	No information provided
Declarations of interest	No information provided
Notes	Only conference abstract was available for the study. Author was contacted but did not provide additional data.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Author confirmed that study was randomised but did not provide further details. Methods not described. Author disclosed that there was a potential bias in the selection of participants.
Allocation concealment (selection bias)	Unclear risk	Only brief abstract available. Information not provided.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Only brief abstract available. Information not provided.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Only brief abstract available. Information not provided.
Incomplete outcome data (attrition bias) All outcomes	High risk	Only brief abstract available. No information provided regarding number of participants who completed the study and completeness of outcome measures.
Selective reporting (reporting bias)	High risk	Only brief abstract available. Not clear if all outcomes were reported. No data for secondary outcomes reported.
Other bias	High risk	Author expressed concerns regarding quality of the study; no additional details provided. No prospective protocol available. No funding sources and declarations of interest reported.