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Randomised double-blind placebo controlled trial of effect of Ginkgo biloba on cognitive function in mild-moderate dementia
DOI 10.1186/ISRCTN45577048
ClinicalTrials.gov identifier
EudraCT number
Public title Randomised double-blind placebo controlled trial of effect of Ginkgo biloba on cognitive function in mild-moderate dementia
Scientific title
Acronym DIGGER
Serial number at source QRD/2001/01/07
Study hypothesis Null Hypothesis: high purity ginkgo biloba extract does not improve cognition quality of life or carer burden in individuals with mild-moderate dementia. NB: this study will also assess the magnitude of the Hawthorne effect in dementia trials.
Lay summary
Ethics approval Received from Multi-centre Research Ethics Committee (ref: MREC/02/6/35).
Study design Randomised double-blind placebo controlled parallel group study
Countries of recruitment United Kingdom
Disease/condition/study domain Dementia
Participants - inclusion criteria 1. Aged 55 years and over
2. Clinician's diagnosis of dementia
3. Presence of a carer
4. Consent of patient and carer
5. Sufficient command of English to complete questionnaires
6. Mini Mental State Examination (MMSE-23) score of 15 - 24
Participants - exclusion criteria 1. Commencement of acetylcholinesterase therapy within two months of recruitment
2. Current anticoagulant therapy
3. Abnormal clotting profile
Anticipated start date 01/04/2003
Anticipated end date 31/12/2005
Status of trial Completed
Patient information material
Target number of participants Target: 200
Interventions 1. The active intervention will be concentrated, standardised Ginkgo biloba extract (25% active Ginkgo-flavoneglycosides), prepared according to accepted guidelines in a 60 mg tablet (EGB-761, Schwabe)
2. The placebo will be 60 mg of inert lactose with 2 mg quinine sulphate
Primary outcome measure(s) Alzheimer's Disease Assessment Scale Cognitive Subscale (ADAS-cog) at six months.
Secondary outcome measure(s) All at six months:
1. Participant: Quality of Life scale in Alzheimer’s disease (QoL-AD), Neuropsychiatric Inventory questionnaire (NPI), Geriatric Evaluation by Relative's Rating Instrument (GERRI), adverse events
2. Carer: European Quality of life questionnaire (EQ-5D), Zarit caregiver Burden Interview (ZBI)
Sources of funding Alzheimer's Society (UK)
Trial website
Publications Results in: http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=17608932
Contact name Dr  James  Warner
  Address Senior Lecturer
Imperial College School of Medicine
St Charles Hospital
Exmoor Street
  City/town London
  Zip/Postcode W10 6DZ
  Country United Kingdom
  Tel +44 (0)20 8962 4101
  Fax +44 (0)20 8960 8112
  Email j.warner@ic.ac.uk
Sponsor Alzheimer's Society (UK)
  Address Gordon House
10 Greencoat Place
  City/town London
  Zip/Postcode SW1P 1PH
  Country United Kingdom
  Tel +44 (0)20 7306 0606
  Fax +44 (0)20 7306 0808
  Email enquiries@alzheimers.org.uk
Date applied 02/08/2002
Last edited 11/07/2007
Date ISRCTN assigned 02/08/2002
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