Table 3 Primary and secondary cognitive and functional outcome measures

Primary Cognitive

Alzheimer's Disease Assessment Scale (ADAS-Cog) [25]

This subscale of the ADAS, measures severity of cognitive dysfunction associated with Alzheimer's disease and is widely used in pharmacological studies of dementia and MCI [51]. The ADAS-Cog has excellent psychometric properties being valid and reliable, and is endorsed as a standard outcome measure [26].

Primary Functional

Bayer-Instrumental Activities of daily Living (B-ADL) [26, 52]

The B-IADL initially developed for pharmaceutical clinical trials to assess deficits in the activities of daily life in community-dwelling individuals with MCI and response to pharmacological agents [26], is a 25-item informant or proxy questionnaire.

Secondary Cognitive

Mini-Mental State Examination (MMSE)[29]

Internationally known brief measure to screen for cognitive impairment [41], with valid and reliable quantitative assessment of severity of cognitive impairment, and is sensitive to changes in cognitive function over time [53].

GP-Cog [54]

Six item self report scale identifying whether patients have greater difficulty functioning in 6 areas of daily life compared to their level of functioning 5-10 years earlier.

Clinical Dementia Rating (CDR) [28]

A commonly used clinical tool for the global assessment of dementia severity, is completed by a clinician after synthesizing information obtained from the patient, informants and any other sources [28].

Subjective Memory Complaint (SMC)

Eight questions were developed to measure SMC including type of memory difficulty, concern level, duration, comparison to peers, and reported by informant, meeting criteria for the assessment of SMC [55].

Life Experience Questionnaire (LEQ)[19]

Questionnaire is a self report questionnaire examining the amount and quality of mental activity a person has engaged in over their life time [19].

Matrices

Matrices, a perceptual subtest of the Wechsler Adult Intelligence Scale-III (WAIS-III) assesses executive functions and requires visual perception, organization, and synthesis of visual spatial information [56].

Similarities

This verbal subtest from the WAIS-III is used to measure verbal conception formation and abstraction [56].

Trail Making Test (TMT)[40] A and B

Trials A and B test speed of attention, sequencing and visual search, and includes a motor response component, whilst B also assesses mental flexibility, an executive function [57].

Logical Memory

The Logical Memory subtest of the Wechsler Memory Scale 3^rd edition (WMS-III) is used to measure both immediate and delayed memory for verbal information.

Benton Visual Retention Test (BVRT)[42]

This widely used visual memory test assesses visual perception and visual constructive abilities as participants are required to draw from memory simple designs [41].

Symbol Digit Modalities Test (SDMT)

SDMT, first published in 1973 by Aaron Smith and subsequently revised in 1982[41] measures divided attention, visual scanning, tracking, and motor speed. It uses a substitution format presenting symbols with matching numbers, and participants are required to name the numbers corresponding to each given symbol.

Category Fluency

Category Verbal Fluency measures verbal production of animal names from semantic memory [58].

Controlled Oral Word Association Test (COWAT)

COWAT is a language based task assesses association fluency, and is often used as a measure of executive functioning. The most commonly used letters are F. A. S. or C. F. and L. based upon word prevalence rates [58].

Memory Awareness Rating Scale-Memory Functioning (MARS-MF) [43]

The MARS-MF is an 11 item self report rating scale of everyday memory functioning. Ratings are made on a 0 - 4 scale where 0 = never and 4 = always, and is usually administered in an interview format [43].