Synonyms

Alzheimer’s disease co-operative study ADL scale for mild cognitive impairment (ADCS-ADL-MCI); Alzheimer’s disease co-operative study ADL scale for severe impairment (ADCS-ADL-sev).

Description

The ADCS-ADL assesses the competence of patients with Alzheimer’s Disease (AD) in basic and instrumental activities of daily living (ADLs). It can be completed by a caregiver in questionnaire format, or administered by a clinician/researcher as a structured interview with a caregiver. All responses should relate to the 4 weeks prior to the time of rating. The six basic ADL items each take an ADL (e.g., eating) and provide descriptions of level of competence, with the rater selecting the most appropriate option (e.g., ate without physical help and used a knife; used a fork or spoon but not a knife; used fingers to eat; was usually fed by someone else). The 16 instrumental ADL items follow the format “In the past 4 weeks, did s/he use the telephone,” with the response options of yes/no/don’t know. If the response is “yes,” a rating is then made regarding his/her competence according to a set of descriptions tailored to that activity (e.g., for the telephone item, whether the person looked up phone numbers and made calls, made calls only to well-known numbers without referring to a directory, made calls only to well-known numbers using a telephone directory, answered the phone but did not make calls, or only spoke when put on the line). Adapted versions of the scale suitable for people with MCI (ADCS-MCI-ADL) and moderate-severe AD (ADCS-ADL-sev) have also been developed. Scores on the 24-item ADCS-ADL range from 0 to 78, those on the 18-item ADCS-MCI-ADL range from 0 to 57, and on the 19-item ADCS-ADL-sev from 0 to 54, where higher scores reflect greater competence (see section “Psychometric Data” for further details). The entire instrument takes 15–30 min to administer.

Historical Background

The ADCS is a United States-based initiative that aims to conduct research informing the prevention and treatment of AD, as well as developing measures for use in people with AD, particularly in clinical trials. The ADCS-ADL was the first ADL scale to be developed for use specifically in clinical trials with people with AD across the range of severity. The 23 items in the standard version were selected from a pool of 45 items based upon a stringent set of psychometric criteria (see Section “Psychometric Data”). Using the same criteria, Galasko et al. (2005) developed a version of the ADCS-ADL for more severely impaired participants, which is known as the ADCS-ADL-sev, and a version for people with MCI has also been developed (ADCS-MCI-ADL, Perneczky et al., 2006). The ADCS-ADL has been used in a variety of clinical trials.

Psychometric Data

Galasko et al. (1997) selected the items for the ADCS-ADL from a pool of 45 items thought to be relevant to the target population on the basis of existing scales and clinical experience. To determine which ADLs were most suitable for inclusion, the 45-item version was administered at baseline, 6 months and 12 months later to 64 elderly controls and 242 people with AD, stratified by MMSE score at baseline assessment. Half of participants were additionally assessed at 1 and 2 months post-baseline. An item was included in the final measure if it fit the criteria that it: was performed either premorbidly or at baseline by >90% of participants (showing it was applicable to the target group), had a kappa agreement statistic at 1–2 months of >0.4 (indicating good test-retest reliability), had a significant correlation with MMSE score (indicating appropriate scaling and validity), and showed decline over 12 months in at least 20% of participants (indicating validity and sensitivity to change).

Galasko et al. (2005) used the same criteria in the development of the ADCS-ADL-sev, based on longitudinal data of 145 patients with Mini-Mental State Examination (MMSE) scores between 0 and 15. Galasko et al. reported good test-retest reliability (baseline-1 month r = 0.94, baseline-2 months r = 0.89, month1–month2 r = 0.94), and there was evidence of convergent validity based upon the strong correlation between ADCS-ADL-sev and other global impairment measures (ADCS-ADL-sev – MMSE r = 0.64; ADCS-ADL-sev – Severe Impairment Battery r = 0.71). The mean score on first test was 25.4 (SD 12.7, maximum obtainable 54), with a mean decline of 5.6 points (SD 7.5) over 6 months and 10.3 points (SD 10.3) over 12 months.

Perneczky et al. (2006) have found that the ADCS-MCI-ADL scale can discriminate people with MCI from control participants (a cut-off score of 52 gives sensitivity of 0.89 and specificity of 0.97).

Clinical Uses

The ADCS-ADL and its variants are the only ADL scales designed with AD specifically in mind, and can provide a fairly detailed assessment of competence in a variety of ADLs. Galasko et al. (2005) state that the measure takes too long to administer for it to be widely adopted in clinical practice, but it would be useful in intervention studies, and the ADL-sev in particular where the severity of the disorder may render measures such as the MMSE unsuitable due to floor effects. The careful selection of items for the ADCS-ADL suggests that they are eminently suitable for use in clinical trials. Perneczky et al. (2006) found that even patients with a diagnosis of Mild Cognitive Impairment exhibit deficits in instrumental ADLs on the ADCS-ADL-MCI, and that scores can successfully discriminate patients with MCI from healthy controls; as such, results from this scale may be useful in forming an MCI diagnosis.

Cross References

Bristol Activities of Daily Living Scale

Disability Assessment for Dementia

Lawton–Brody iADL Scale

The Activities of Daily Living Questionnaire