Evaluating ADCS-ADL-MCI for Mild Cognitive Impairment

The ADCS-ADL-MCI is a functional evaluation scale that assesses the ability of patients to perform ADLs (with recall "In the past 4 weeks") through a structured questionnaire administered to the informant/carer by a physician or qualified rater [21 (link)]. The ADCS-ADL-MCI was derived from its parent measure, the ADCS-ADL [12 (link)], and adapted to be suitable for MCI patients. Two forms of the ADCS-ADL-MCI are the 18-item and the 24-item version. While the 24-item version was administered as part of the ADC-008 trial, the 18-item version is explored in the present study due to practical considerations (i.e., its use in current clinical trials such as the phase 3 aducanumab trials EMERGE [NCT 02484547] and ENGAGE [NCT 02477800]). Items in the measure predominantly include IADLs, such as balancing a checkbook, navigating outside the home, shopping, using household appliances, or finding personal belongings. Physically getting dressed and the ability to be left alone are also being assessed. The 18-item ADCS-ADL-MCI is scored from 0–53 based on the subject's degree of independence in performing specific tasks (i.e., independent, partially independent, fully dependent). Except for item 3 (i.e., 'Regarding physically getting dressed, which best describes his/her usual performance in the past 4 weeks?', with response options ranging from '0 = Someone else dressed him/her' to '4 = Dressed completely without supervision or physical help'), all other items follow a gating response format [22 (link)]. That is, the first step of the item asks about whether the patient performed the specific task – and in case of endorsement – the second step usually follows the response format ranging from '1 = With physical help' to '3 = Without supervision or help' or a similar wording probing the details and manner of performing the specific task. Some items include four to five response options that describe how the IADL was performed (rather than three response options as in the more standardized response format for items 1, 2, 4, 5, and 7). Further, the second step of some items includes subquestions that are more descriptive regarding a particular activity (such as watching television), including only 'yes' and 'no' response options. Lower scores on the measure denote more substantial impairment [12 (link), 16 (link)]. In this study, the ADCS-ADL-MCI was assessed at baseline and months 6, 12, 18, 24 and 36 for patients with MCI. Per the ADC-008 trial design, patients who progressed to mild AD dementia were moved into an open-label study with donepezil, and where the ADCS-ADL-MCI was not included in that study design. Consequently, these patients are no longer included in the analysis after having progressed to mild AD dementia and, therefore, this study does not provide any information on the measurement properties of the ADCS-ADL-MCI as applicable to patients with mild AD dementia.