The following table gives a list of terms used in ALOIS and their definitions

Absolute Number of Participants The total/highest number of participants to take part in a trial including those who are part of a control group at the time of randomization/allocation
Added to ALOIS All records are tagged with Added to ALOIS (month year). This is so that users can perform easy monthly searches and retrieve what is new on ALOIS within a certain month
Advanced Search A search option for users of ALOIS. It allows users to search particular fields of a study’s parent record unlike the keyword search which search the whole record. For more on the Advanced search in ALOIS see the Search Tips page
ALOIS ALOIS stands for the ALzheimer’s and cOgnitive Improvement Studies register. It was named after Alois Alzheimer who first described the disease in 1901. ALOIS contains records of RCTs and CCTs in the areas of dementia treatment, dementia prevention and cognitive enhancement in healthy people. It also contains details of some Diagnostic Test Accuracy studies in the area of dementia
Blinding The process of preventing those involved in a trial from knowing to which comparison group a particular participant belongs. The risk of bias is minimised when as few people as possible know who is receiving the experimental intervention and who the control intervention. Participants, caregivers, outcome assessors, and analysts are all candidates for being blinded. Blinding of certain groups is not always possible, for example surgeons in surgical trials. The terms single blind, double blind and triple blind are in common use, but are not used consistently and so are ambiguous unless the specific people who are blinded are listed
Caregiver Focused This refers to studies where the main focus of the intervention was on the effect on caregivers
CCT Controlled Clinical Trial. it refers to trials using quasi-randomization, or trials where double blinding was used but randomization was not mentioned
CDCIG See Cochrane Dementia and Cognitive Improvement Group, The
Cochrane Collaboration, The An international organization that aims to help people make well-informed decisions about health care by preparing, maintaining, and ensuring the accessibility of systematic reviews of the effects of healthcare interventions
Cochrane Dementia and Cognitive Improvement Group, The A registered collaborative review group or entity within the Cochrane Collaboration
Coding The process by which information is manually extracted from reports of trials and entered into the parent record of the study
Cognitive Enhancement Refers to studies that have used an intervention that may improve mental function in areas such as: cognition, memory, concentration
Co-morbid Health Condition The presence of one or more diseases or conditions other than those of primary interest. In a study looking at treatment for one disease or condition, some of the individuals may have other diseases or conditions that could affect their outcomes. (A co-morbidity may be a confounder
Contact ALOIS Users can contact ALOIS with any questions, queries or comments:
Cross-sectional Study A study don at one time and not over a period of time 
Current Status of Trial Every study in ALOIS has been classified according to its status as reported in the text. A study can be: Planned; Protocol; Ongoing; Closed; Completed; Aborted
Diagnostic Test Accuracy Study As opposed to an Intervention study, a Diagnostic Test Accuracy study is one in which two or more diagnostic or prognostic tests are compared
Double-blind A term used to indicate that both the investigator and the participant were blind to the nature of the intervention
DTA See Diagnostic Test Accuracy study
DOI Digital Object Identifier. In the parent record of a study, there is a field called Related Cochrane Reviews. The DOI of a related review is pasted here. A user can copy and paste the DOI into Google to retrieve the abstract of the Cochrane review
Email Us Users can contact the ALOIS team at
Embase A European medical/healthcare database. The ALOIS team search this database monthly for reports of new RCTs and CCTs in the areas of dementia prevention, treatment and cognitive enhancement
Fields Refers to the different fields within a parent record
Health Status/Diagnosis The main health condition, disease or problem for which the intervention in the trial is primarily aimed at
Index Test This refers to the test under scrutiny in a Diagnostic Test Accuracy Study
In-process Some studies records are given the status In-process. This means that while some information about the study has been added to ALOIS, there is more to come shortly
Intervention The regimens in all comparison groups, including placebo and no-treatment arms. See also treatment, experimental intervention and control
Intervention Study A study that compares the outcomes of a particular intervention or interventions on two or more groups of people. ALOIS contains Intervention studies and Diagnostic Test Accuracy studies (DTAs)
Key Points of Study This is field in the parent record of a study on ALOIS. It is a field which is manually completed by an ALOIS coder. The aim of the field is to highlight quickly some of the key characteristics of the study
Keyword Search A search option in ALOIS which allows users to enter in any text they wish. Once the search has been submitted, the whole parent record of every study is searched for terms that match the search criteria entered. Boolean operators (AND/OR) can be used. For more on the Keyword search in ALOIS see the Search Tips page
Longitudinal Study On ALOIS a DTA study can be classified a Longitudinal study. By this we mean a study that has been conducted over a long period of time and that involved repeated collection of data at different points in time
Main Diagnostic Criteria This a field within the parent record of a study on ALOIS. It refers to the criteria used for the selection of participants to include within the trial
MCI Mild Cognitive Impairment. Individuals with MCI usually have difficulty with memory but can largely function in everyday activities
Medline A medical/healthcare database produced by the US National Library of Medicine. This source is searched by the ALOIS team on a monthly basis for new reports of RCT sot CCTs in the areas of dementia prevention and treatment and cognitive enhancement in healthy
Mild Cognitive Impairment See MCI
No Review Yet  In a study's parent record there is a field called "Related Cochrane Reviews or Protocols". If there is no Cochrane review that covers the scope of the study then this field is coded with the term "No review yet". A keyword search on the phrase "no review yet" will retrieve all the studies for which there is as yet no Cochrane review
Open-label A clinical trial in which the investigator and participant are aware which intervention is being used for which participant (i.e. not blinded). The term is also used to describe an intervention with no control
Outcome(s) A component of a participant's clinical and functional status after an intervention has been applied, that is used to assess the effectiveness of an intervention. Primary Outcome: the outcome of greatest importance; Secondary Outcome: An outcome used to evaluate additional effects of the intervention deemed a priori as being less important than the primary outcomes.
Parent Record The term used to refer to a page on ALOIS of extracted information pertaining to a study. Every study on ALOIS has a parent record
Placebo An inactive substance or procedure administered to a participant, usually to compare its effects with those of a real drug or other intervention, but sometimes for the psychological benefit to the participant through a belief that s/he is receiving treatment. Placebos are used in clinical trials to blind people to their treatment allocation. Placebos should be indistinguishable from the active intervention to ensure adequate blinding
Planned Refers to a possible status of a trial and is the stage before the recruitment of participants
Primary Outcome See Outcome(s)
Primary Prevention Primary prevention studies are those which state as one of their aims the hypothesis that the intervention to be used may help preclude the onset or development of dementia
Randomized Controlled Trial See RCT
RCT Randomized Controlled Trial. An experiment in which two or more interventions are compared having been randomly allocated to participants using mathematical techniques. This allocation can be single-, double- or triple-blind
Reference Standard This term refers to a test used as the comparator in a Diagnostic Test accuracy study
References The section of a study’s parent record that list the references to the papers and documents found concerning that study. The reference(s) in bold are those which were found to have the most information available about that study
Secondary Outcome See Outcome(s)
Sensitive Search A measure of a search’s ability to correctly identify relevant articles. It is the proportion of all relevant articles from all searches that were identified by the particular search of interest. It is calculated as follows: Sensitivity = Number of relevant articles identified by the search/Total number of relevant articles from all searches
Single-blind A term used when investigators are aware of the intervention allocation but the participants are not
Study-based ALOIS is a study-based register. That means that it is a register made up of studies rather than references. References from various sources that relate to the same study/trial are grouped together under the same study/parent record
Study Design For intervention studies, every study in ALOIS is classified as either RCT (Randomized Controlled Trial), CCT (Controlled Clinical Trial; Open-label; Other

For DTA (Diagnostic Test Accuracy) studies, each study is classified as Cross-sectional, Longitudinal, RCT, Other

Study List Users can bookmark studies of interest to them and create their own list of studies in ALOIS. In order to be able to do this users do need to create an account. The feature is free and it takes only a minute to create an account
Study Name The study name consists of the acromyn or trial name, the first author of the earliest reference and the year of the first reference if available
Submit a Study Users of ALOIS can submit a study to the site. They simply click on the left hand side link ‘Submit a study’ and fill in the details they have
Systematic Reviews A review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyse data from the studies that are included in the review. Statistical methods (meta-analysis) may or may not be used to analyse and summarise the results of the included studies
Treatment Dementia Refers to studies in which the intervention was aimed at threating participants with an existing diagnosis of dementia
Treatment MCI Refers to studies in which the intervention was aimed at treating participants with an existing diagnosis of Mild Cognitive Impairment (and not those diagnosed with having dementia)
Triple-Blind A term that usually refers to the participant, the investigator and the person administering the intervention were all blind to what was being given
Unit of Allocation The unit that is assigned to the alternative interventions being investigated in a trial. Most commonly, the unit will be an individual person but, in a cluster randomised trial, groups of people will be assigned together to one or the other of the interventions

 Page last updated: 08 July 2009