Functional Activities Questionnaire (FAQ)

1. Abstract

The Functional Activities Questionnaire (FAQ) is an established, clinician-administered or informant-rated psychometric instrument designed to quantify independence in instrumental activities of daily living (IADLs) among older community-dwelling adults and clinical populations undergoing evaluation for cognitive impairment, mild cognitive impairment (MCI), and dementia, particularly Alzheimer’s disease. Developed by Robert I. Pfeffer and colleagues in 1982 and revised in 1984, the FAQ comprises 10 distinct, complex functional domains: financial management, administrative and record-keeping tasks, shopping, playing games of skill or hobbies, preparing hot beverages, cooking balanced meals, following current events, tracking media or literary plots, recalling appointments and family events, and traveling independently outside the neighborhood.

Informants (typically a spouse, adult child, or primary caregiver with intimate knowledge of the individual’s baseline capacity) rate the individual’s degree of functional independence across these 10 items. Responses are scored along a graded functional continuum ranging from 0 (normal performance or never did the activity but could execute it normally now) to 3 (dependent; completely taken over by another individual), generating a cumulative composite score ranging from 0 to 30. Higher total scores denote worsening functional dependence. Extensive psychometric investigations have affirmed the FAQ’s superior diagnostic utility, demonstrating exceptional internal consistency (Cronbach’s alpha typically ranging from .87 to .94), robust inter-rater and test-retest reliability ($r > .90$), and marked sensitivity (.80–.90) and specificity (.80–.95) in distinguishing healthy aging from early-stage neurodegenerative syndromes. By capturing the functional threshold where cognitive deficits compromise everyday autonomy, the FAQ operationalizes diagnostic criteria established by the American Psychological Association and the National Institute on Aging-Alzheimer’s Association (NIA-AA), serving as a gold-standard assessment in epidemiological surveys, clinical trials, and geriatric clinical practice.

2. Keywords

Functional Activities Questionnaire, FAQ, instrumental activities of daily living, IADL, mild cognitive impairment, dementia, Alzheimer’s disease, functional assessment, geriatric psychometrics, informant report, neuropsychological evaluation

3. Authors

The Functional Activities Questionnaire was conceptualized, operationalized, and psychometrically validated by a multidisciplinary team of epidemiologists, neurologists, and biostatisticians led by Robert I. Pfeffer, M.D.

• Robert I. Pfeffer, M.D.: Department of Neurology and Department of Medicine, College of Medicine, University of California, Irvine, California, United States. Dr. Pfeffer served as the principal investigator of the landmark longitudinal community-based epidemiological cohorts examining cognitive decline and functional failure in older adults in Orange County, California.
• Taro T. Kurosaki, M.S.: Department of Community and Environmental Medicine and Biostatistics Core, University of California, Irvine, California, United States. Mr. Kurosaki oversaw the statistical architecture, item-response formulations, and psychometric validation models.
• C. Harold Harrah, Jr., Ph.D.: Collaborative researcher and methodologist at the University of California, Irvine, who participated in the field testing, epidemiological stratification, and construct validation.
• John M. Chance, Ph.D.: Co-investigator and biostatistician who contributed to the longitudinal evaluation, test-retest reliability designs, and the development of the broader Mental Function Index battery.

Inquiries regarding the historical epidemiological datasets are generally archived through academic repositories affiliated with the University of California, Irvine, and subsequent updates coordinated through the National Alzheimer’s Coordinating Center (NACC), which incorporates the FAQ into its standardized Uniform Data Set (UDS).

4. Purpose

The primary clinical and psychometric objective of the Functional Activities Questionnaire (FAQ) is to provide an objective, standardized, and ecologically valid quantification of complex functional capacities that rely on high-order neurocognitive integrity. In normal cognitive aging, basic activities of daily living (BADLs)—such as dressing, bathing, toileting, and feeding—remain remarkably resilient and intact until late-stage neuropathology ensues. Conversely, instrumental activities of daily living (IADLs), which require intricate executive functions, working memory, spatial orientation, prospective memory, and abstract judgment, begin deteriorating during the transition between preclinical neurodegeneration and manifest dementia. The FAQ was constructed specifically to interrogate this fragile boundary zone, offering clinical utility that traditional BADL indices (e.g., the Katz ADL Index or Barthel Index) cannot capture.

A critical diagnostic challenge in geriatric neuropsychiatry is the formal differentiation between mild cognitive impairment (MCI) and overt dementia. According to international consensus criteria, including the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for Major versus Mild Neurocognitive Disorder, this distinction rests decisively on whether cognitive deficits are severe enough to interfere with independence in everyday activities. While an individual with MCI experiences objective cognitive deficits verified by psychometric testing, their functional autonomy in daily life is largely preserved, although complex tasks may require greater effort, compensatory strategies, or minor accommodations. In contrast, the emergence of overt functional dependency signals the conversion to dementia. The FAQ provides a continuous metric to document this functional inflection point, establishing empirically grounded cutoff thresholds that guide clinicians toward accurate diagnostic categorization.

Beyond baseline differential diagnosis, the FAQ fulfills an essential purpose in longitudinal clinical trials and treatment monitoring. Because cognitive test performance can fluctuate due to test-retest learning effects, educational disparities, cultural biases, sensory deficits, or test anxiety, cognitive scores alone do not always accurately mirror real-world functional decline or real-world therapeutic efficacy. The FAQ functions as a reliable proxy for real-world functioning, serving as a primary or key secondary outcome measure in clinical trials evaluating disease-modifying therapies, such as anti-amyloid monoclonal antibodies, cholinesterase inhibitors, and non-pharmacological behavioral interventions. Furthermore, in clinical practice, the tool informs clinical risk management: identifying high scores in items measuring financial management, medication adherence, stove operation, or independent transit provides direct, actionable guidance for family counseling, home safety modifications, legal power-of-attorney planning, and driving cessation evaluations.

5. Psychological Construct

The FAQ operationalizes the psychological and behavioral construct of Instrumental Functional Competence, specifically defined as the capacity to independently execute cognitively demanding tasks necessary for autonomous societal living. Rather than assessing isolated sensorimotor or physiological capabilities, the FAQ captures complex neurobehavioral competencies that depend on multiple, distributed brain networks. The construct encompasses ten discrete operational domains:

Financial Management (Item 1)

This domain captures the individual’s ability to maintain personal financial accountability, including writing checks, balancing bank accounts, keeping financial ledgers, and paying recurring utility and residential bills. Psychologically, this task requires intact working memory, numerical calculation (acalculia screening), error detection, sustained attention, and abstract reasoning. Impairment in this domain is frequently one of the earliest heralds of underlying neurodegenerative pathology, leaving older adults vulnerable to financial exploitation, missed payments, or unintended overdrawing of funds.

Administrative and Legal Problem Solving (Item 2)

This dimension assesses the capacity to process intricate institutional documentation, such as completing complex tax forms, processing Social Security paperwork, interpreting health insurance policies, and navigating civic bureaucracies. This domain taps into advanced executive functioning, fluid reasoning, cognitive flexibility, verbal comprehension of legalistic syntax, and multi-step organizational strategy. Functional loss here indicates a breakdown in navigating modern societal structures without proxy intervention.

Independent Community Procurement / Shopping (Item 3)

Procuring groceries, clothing, and household necessities alone demands an integration of topographical memory, spatial navigation, semantic knowledge, selective attention, decision-making, and prospective memory. The individual must navigate the commercial environment, select items aligned with nutritional and logistical needs, manage payment transactions, and safely return home. Deficits manifest as returning with inappropriate items, buying duplicates, or becoming disoriented in large shopping environments.

Complex Leisure and Hobbies (Item 4)

Engaging in structured games of skill (e.g., bridge, chess, intricate card games) or hobbies (e.g., carpentry, painting, stamp collecting) requires complex rule retention, strategic forward planning, visual-spatial integration, fine motor coordination, and mental flexibility. Loss of engagement in lifelong hobbies is often misattributed to depression; however, the FAQ isolates cognitive deterioration wherein the individual abandons the activity because they can no longer adhere to rules or conceptualize the procedural steps.

Immediate Domestic Safety: Hot Water and Beverage Preparation (Item 5)

This domain evaluates procedural memory, sequential task execution, and domestic safety awareness within a foundational kitchen environment: boiling water, preparing a hot beverage, and ensuring heating appliances are extinguished. The critical psychometric and clinical marker here is safety awareness: forgetting to turn off gas or electric burners reflects profound prospective memory failure and attentional lapses, posing imminent domestic hazards.

Nutritional Planning and Meal Preparation (Item 6)

Preparing a nutritionally balanced meal (involving multiple courses, such as meat, vegetables, and complex staples) necessitates multi-stage sequencing, time management, divided attention, and conceptual knowledge. Individuals with early executive breakdown often retreat to monotonous, pre-packaged, or single-step meals (e.g., frozen microwaved dinners) because coordinating multi-pot culinary tasks concurrently surpasses their working memory and cognitive capacity.

Environmental and Political Awareness: Current Events (Item 7)

Monitoring local, national, or international affairs reflects ongoing cognitive engagement with the broader socio-political ecosystem. This domain assesses episodic memory for newly acquired societal information, semantic memory integration, and receptive communication channels. Individuals exhibiting cognitive decline systematically disengage from news media and show marked temporal disorientation regarding prominent public figures or current events.

Information Processing and Narrative Comprehension (Item 8)

This item evaluates the capacity to sustain attention across an extended narrative arc—such as following a 60-minute television program or extracting meaningful thematic content from books and periodicals. Cognitive processes involved include sustained and selective attention, working memory updating, narrative coherence tracking, and inferential reasoning. Patients experiencing functional decline often lose the narrative thread, confuse character identities, or fail to appreciate humor, nuance, and thematic continuity.

Prospective Memory and Personal Scheduling (Item 9)

Remembering scheduled medical appointments, planned family celebrations, anniversaries, maintenance obligations, and time-critical medication regimens taps prospective memory (remembering to perform an intended action at a specific future juncture) and organizational scaffolding. As memory fails, individuals shift from internal mnemonic control to an over-reliance on external aids (checklists, calendars), eventually progressing to missed critical commitments and dangerous non-compliance with medication protocols.

Topographical Navigation and Independent Travel (Item 10)

Traveling outside one’s familiar immediate neighborhood—whether by driving an automobile, navigating public bus routes, coordinating multi-leg transit systems, or walking—demands sophisticated visuospatial orientation, divided attention, processing speed, spatial cognitive mapping, and rapid situational decision-making. Navigational errors, getting lost in previously familiar districts, or voluntarily relinquishing driving due to spatial confusion represent critical indicators of moderate functional decline.

6. Theoretical Framework

The theoretical framework underlying the Functional Activities Questionnaire sits at the intersection of cognitive neuropsychology, ecological psychometrics, and the hierarchical model of functional loss in gerontology.

The Hierarchical Degradation Model of Functional Independence

The FAQ’s foundational paradigm builds upon the classical functional continuum established by M. Powell Lawton and Elaine M. Brody (1969), who differentiated between physical Basic Activities of Daily Living (BADLs) and Instrumental Activities of Daily Living (IADLs). Under the hierarchical degradation hypothesis, functional abilities decline in a reverse evolutionary sequence relative to their developmental acquisition in childhood (often termed ‘retrogenesis’ by Barry Reisberg). High-order, culturally learned, tool-mediated activities requiring complex executive coordination (IADLs, measured by the FAQ) deteriorate first when neocortical and hippocampal synaptic networks suffer neurodegenerative insult. Basic self-care routines (BADLs), which are mediated by deeply ingrained motor programs and subcortical circuitry, remain resilient until advanced stages of cerebral atrophy.

Ecological Validity and the Informant-Rating Paradigm

A second theoretical pillar centers on the ecological validity of proxy-based functional observation versus direct laboratory psychometric testing. Standardized performance-based cognitive batteries (such as the Mini-Mental State Examination or the Montreal Cognitive Assessment) assess cognitive constructs in sterile, quiet, distraction-free environments. However, these brief cross-sectional tests cannot capture how cognitive deficits interact with real-world complexities, environmental distractions, sensory adaptations, or fatigue over extended temporal intervals.

Furthermore, individuals with frontal-executive impairment or early Alzheimer’s disease frequently exhibit anosognosia—a neurobiologically driven lack of insight or denial regarding their own cognitive and functional failures. Consequently, self-report measures in this population are systematically flawed and artificially deflated. By utilizing a collateral informant (a close relative or caregiver who observes the subject across diverse diurnal settings), the FAQ eliminates anosognosic distortion and captures the authentic ecological expression of neurocognitive failure.

The Premorbid Baseline and Lifelong Habit Adjustment Logic

Pfeffer and colleagues introduced an innovative theoretical control mechanism within the FAQ’s structural logic: the distinction between cognitive inability and premorbid lifestyle/gender role socialization. Prior to the FAQ, many functional instruments produced significant false-positive classifications due to sociodemographic biases. For instance, an older male from an early-20th-century cohort might never have prepared a meal, washed dishes, or balanced household records, not because of neurological failure, but because of rigid cultural gender roles. Conversely, an older female might never have managed tax accounts or vehicle maintenance.

Pfeffer’s design explicitly addresses this confounding factor through specialized response categories: ‘Never did [the activity] and would find quite difficult to start now’ versus ‘Didn’t do routinely, but can do normally now should they have to’. By establishing whether non-performance stems from lifelong habit versus emergent cognitive incapacity, the FAQ isolates true pathological deterioration from premorbid cultural behavioral patterns.

7. Validity

The Functional Activities Questionnaire has been subjected to rigorous construct, criterion, convergent, and discriminant validation protocols across epidemiological samples, memory clinic registries, and diverse international populations.

Criterion and Diagnostic Predictive Validity

In their seminal validation cohorts comprising community-dwelling older adults and clinically diagnosed dementia patients, Pfeffer et al. (1982, 1984) demonstrated that the FAQ exhibited strong diagnostic accuracy in separating normal aging from dementia. Receiver Operating Characteristic (ROC) analyses consistently yielded areas under the curve (AUC) ranging between .88 and .97. Using the established clinical cutoff threshold of ≥ 9 (indicative of significant functional impairment across multiple domains), the FAQ demonstrated a sensitivity of 85% and a specificity of 81% for detecting dementia. When applied to differentiate mild cognitive impairment (MCI) from healthy controls or very mild dementia, optimized cutoff scores (such as ≥ 5 or ≥ 6) demonstrate high diagnostic sensitivity (.83) and specificity (.82).

Longitudinal predictive studies have validated that FAQ scores in individuals with amnestic MCI reliably predict impending conversion to probable Alzheimer’s disease. Within the National Alzheimer’s Coordinating Center (NACC) database cohorts, elevated baseline FAQ scores significantly increased the hazard ratio of progressing to dementia over a 3-to-5-year surveillance window, even after controlling for age, education, APOE ε4 carrier status, and baseline cognitive scores.

Convergent Validity

The FAQ correlates strongly with established global cognitive measures and functional rating batteries:

• Mini-Mental State Examination (MMSE): FAQ scores demonstrate robust negative correlations with MMSE performance, typically ranging from $r = -.58$ to $r = -.78$ ($p < .001$), reflecting that lower cognitive performance corresponds directly with higher functional dependence.
• Clinical Dementia Rating (CDR): The FAQ shows powerful convergence with the CDR Sum of Boxes (CDR-SB), exhibiting correlation coefficients exceeding $r = .80$ to $.88$, underscoring that both scales tap shared variance in neurodegenerative progression.
• Lawton IADL Scale: Significant inverse correlations ($r = -.75$ to $-.85$) substantiate that the FAQ operationalizes the same broad instrumental construct while providing greater sensitivity to subtle executive nuances.
• Neuropsychological Tests of Executive Function: Specific item-level and composite FAQ scores correlate significantly with formal laboratory executive tests, including the Trail Making Test Part B, the Wisconsin Card Sorting Test, and semantic verbal fluency tasks ($r = .45$ to $.65$).

Discriminant Validity

The FAQ exhibits clear discriminant validity against measures of pure physical disability and primary affective disorders. Correlations between the FAQ and the Katz Index of Independence in Basic Activities of Daily Living in early-stage cognitive cohorts are modest ($r = .25$ to $.35$), confirming that the FAQ selectively evaluates complex cognitive-functional integration rather than basic motoric self-care. Similarly, discriminant analyses demonstrate that FAQ scores remain robustly predictive of dementia even after partialing out depressive symptoms measured by the Geriatric Depression Scale (GDS), confirming that functional declines registered on the FAQ are not merely artifacts of pseudo-dementia or affective apathy.

8. Reliability

The psychometric reliability of the FAQ has been comprehensively established across multiple independent cohorts, confirming that the scale provides consistent, stable, and reproducible measurements.

Internal Consistency

Internal consistency metrics for the 10-item instrument are consistently high across diverse clinical and epidemiological cohorts. In the initial standardization investigations by Pfeffer et al. (1982), Cronbach’s alpha was calculated at .94 for heterogeneous community and clinical samples. Subsequent studies across varied demographic groups (e.g., in the NACC datasets, European population cohorts, and Latin American validation studies) have routinely yielded alpha coefficients ranging between .87 and .94. Corrected item-total correlations across the 10 items typically exceed .60, with complex items such as financial record keeping, managing administrative affairs, and meal preparation frequently exhibiting item-total correlations above .75, indicating high internal coherence among the items.

Test-Retest Reliability

The temporal stability of the FAQ has been evaluated across short-to-moderate test-retest intervals where underlying biological progression is negligible. Pfeffer et al. (1984) documented a test-retest reliability coefficient of $r = .97$ over a 1-to-3-week interval among stable community-dwelling elderly participants. In multi-center validation cohorts, intra-class correlation coefficients (ICC) for the total score over a 4-to-6-week period have consistently remained above .90 (ICC = .91–.95), confirming that the instrument exhibits minimal measurement error in the absence of true clinical change.

Inter-Rater Reliability

Because the FAQ relies on an informant’s observations, inter-rater reliability has been scrutinized by comparing evaluations of the same patient provided by different collateral sources (e.g., primary spousal caregiver versus an adult child) or independent clinicians scoring the structured interview simultaneously. Studies demonstrate high inter-rater concordance, with weighted kappa coefficients for individual items ranging from .70 to .90 and overall composite score intraclass correlations exceeding .85. Discrepancies, when present, typically stem from differences in the amount of daily contact between the informant and the patient rather than ambiguity in the scoring rubrics.

9. Factor Analysis

Extensive exploratory factor analyses (EFA) and confirmatory factor analyses (CFA) have been conducted on the FAQ, evaluating whether instrumental functioning operates as a strictly unidimensional construct or reflects multidimensional cognitive-behavioral sub-domains.

Unidimensional Architecture vs. Hierarchical Factor Models

In original factor analytic work conducted by Pfeffer et al., principal component analysis revealed that a dominant, robust single general factor accounted for the vast majority of the total variance (frequently exceeding 55% to 65% of the total variance), with an eigenvalue substantially higher than any subsequent factor (often > 5.5). This strong primary factor supports the clinical practice of summing all 10 items into a single composite index of functional dependence.

However, subsequent contemporary confirmatory factor analytic studies utilizing larger, diverse cohorts (such as the NACC and ADNI registries) have demonstrated that a two-factor oblique model or a bifactor model provides a superior empirical fit to the data compared to a simple unidimensional structure:

• Factor 1: High-Order Executive / Cognitive IADLs: This factor typically incorporates Items 1 (financial tasks), 2 (tax/legal documents), 7 (tracking current events), 8 (comprehending media/books), and 9 (prospective memory/appointments). These tasks are heavily loaded with executive control, abstract reasoning, and episodic recall. Factor loadings for these items typically range between .72 and .88.
• Factor 2: Practical / Domestic and Spatial IADLs: This factor comprises Items 3 (shopping alone), 4 (hobbies/games), 5 (heating water/coffee safely), 6 (cooking balanced meals), and 10 (traveling out of neighborhood). These activities depend heavily on procedural routines, visuospatial mapping, and environmental navigation. Standardized loadings for these items typically range between .65 and .84.

Model Fit Indices

In structural equation modeling (SEM) evaluations, the two-factor oblique structure and the bifactor model have yielded excellent goodness-of-fit parameters:

• Comparative Fit Index (CFI): .97 to .99
• Tucker-Lewis Index (TLI): .96 to .98
• Root Mean Square Error of Approximation (RMSEA): .042 to .058 (90% CI [.035, .064])
• Standardized Root Mean Square Residual (SRMR): .031 to .042

Item response theory (IRT) analyses (specifically graded response models) further confirm that Items 1 (finances) and 2 (taxes/business affairs) offer the highest psychometric information and discriminative precision at the mildest stages of functional loss ($ heta$ levels near 0.0 to +1.0 standard deviations), whereas Items 5 (turning off the stove) and 10 (getting lost when traveling) provide maximum measurement precision at more severe levels of functional decline ($ heta > +1.5$).

10. Instrument / Measurement Tool

The FAQ is a structured, standardized informant rating questionnaire designed for rapid administration in clinical or research settings. The essential characteristics and administration parameters of the tool are summarized below:

• Instrument Name: Functional Activities Questionnaire (FAQ)
• Instrument Authors: Robert I. Pfeffer, Taro T. Kurosaki, C. Harold Harrah, Jr., and John M. Chance (1982, revised 1984)
• Administration Format: Informant-based rating scale administered via structured clinical interview, paper-and-pencil questionnaire, or electronic clinical outcome assessment (eCOA). Can also be completed independently by a knowledgeable collateral source (spouse, adult child, caregiver).
• Target Population: Older community-dwelling adults, geriatric outpatients, and individuals undergoing clinical evaluation for suspected MCI, Alzheimer’s disease, vascular dementia, frontotemporal dementia, or related neurocognitive disorders.
• Item Count: 10 distinct, ecologically valid instrumental activity domains.
• Estimated Administration Time: Approximately 5 to 10 minutes.
• Response Coding and Graded Continuum: Each of the 10 activities is rated across a structured categorical hierarchy designed to capture baseline competence versus emergent pathological dependency:
  • Dependent (Score = 3): Someone has recently taken over this activity completely or almost completely.
  • Requires assistance (Score = 2): Requires frequent advice, substantial assistance, or makes recurrent severe errors.
  • Has difficulty but does by self (Score = 1): Executes the task without advice or assistance, but experiences more difficulty than in the past, takes longer, or performs less effectively.
  • Normal (Score = 0): Executes the activity without any difficulty, advice, or assistance.
  • Never did [the activity] but could do now (Score = 0): Did not routinely perform the task in the past due to habit or domestic division of labor, but has the cognitive capacity to perform it normally now if required.
  • Never did and would have difficulty now (Score = 1): Never performed the task in the past and would find it quite difficult to initiate or learn now.
• Total Score Calculation and Interpretation:
  • The total composite score is derived by summing the point values assigned to each of the 10 items.
  • Score Range: 0 to 30.
  • Normal Functioning: Scores from 0 to 4 generally reflect intact instrumental independence.
  • Borderline / Mild Functional Impairment (MCI threshold): Scores from 5 to 8 typically represent emerging functional difficulties consistent with Mild Cognitive Impairment, particularly when deficits concentrate in complex executive activities (finances, taxes).
  • Substantial Functional Dependency (Dementia threshold): A cumulative score of ≥ 9 (or ≥ 3 dependent activities) is the standard psychometric cutoff signifying functional failure characteristic of overt dementia.
  • Severe Functional Dependency: Scores approaching 20 to 30 indicate comprehensive functional breakdown requiring extensive daily supervision and full proxy management across domestic and community life.

11. Permissions & Fee and Test Year

The Functional Activities Questionnaire was originally published in 1982 in the Journal of Gerontology and refined in subsequent epidemiological investigations in 1984 in the American Journal of Epidemiology. The original developmental research was supported by public research grants from the United States Public Health Service and the National Institutes of Health (NIH).

• Publication Year: 1982 (Revised 1984).
• Copyright Status and Academic Use: The FAQ is generally considered to reside in the public domain for academic, non-commercial clinical, and educational purposes. As an instrument developed under federal grant support and widely distributed across scientific literature, researchers and clinicians may administer the tool without paying licensing fees or royalties.
• Commercial and Clinical Trial Use: Commercial entities, pharmaceutical sponsors, contract research organizations (CROs), and digital health software developers incorporating the FAQ into proprietary electronic platforms or sponsored clinical trials should verify permissions, citations, and derivative-work rights through the original publishers (Oxford University Press / The Gerontological Society of America) or affiliated academic technology transfer offices.
• Official Versions and Institutional Endorsements: Standardized, validated English and translated variations of the FAQ are officially archived and freely accessible to qualified researchers through the National Alzheimer’s Coordinating Center (NACC) as part of the Uniform Data Set (UDS Form B7: Functional Assessment – FAQ).

12. References

The following peer-reviewed citations provide foundational psychometric validation and clinical application evidence for the Functional Activities Questionnaire:

• Albert, M. S., DeKosky, S. T., Dickson, D., Dubois, B., Feldman, H. H., Fox, N. C., Gamst, A., Holtzman, D. M., Jagust, W. J., Petersen, R. C., Snyder, P. J., Carrillo, M. C., Thies, B., & Phelps, C. H. (2011). The diagnosis of mild cognitive impairment due to Alzheimer’s disease: Recommendations from the National Institute on Aging-Alzheimer’s Association workgroups on diagnostic guidelines for Alzheimer’s disease. Alzheimer’s & Dementia, 7(3), 270–279. https://doi.org/10.1016/j.jalz.2011.03.008
• Lawton, M. P., & Brody, E. M. (1969). Assessment of older people: Self-maintaining and instrumental activities of daily living. The Gerontologist, 9(3_Part_1), 179–186. https://doi.org/10.1093/geront/9.3_Part_1.179
• Marshall, G. A., Amariglio, R. E., Sperling, R. A., & Rentz, D. M. (2012). Instrumental activities of daily living: Clinical relevance in preclinical Alzheimer disease. Nature Reviews Neurology, 8(8), 457–466. https://doi.org/10.1038/nrneurol.2012.122
• McDowell, I. (2006). Measuring Health: A Guide to Rating Scales and Questionnaires (3rd ed.). Oxford University Press. https://doi.org/10.1093/acprof:oso/9780195165678.001.0001
• Pfeffer, R. I., Kurosaki, T. T., Harrah, C. H., Jr., Chance, J. M., & Filos, S. (1982). Measurement of functional activities in older adults in the community. Journal of Gerontology, 37(3), 323–329. https://doi.org/10.1093/geronj/37.3.323
• Pfeffer, R. I., Kurosaki, T. T., Harrah, C. H., Jr., Chance, J. M., Bates, D., Detels, R., Treiman, D. M., & McDowell, I. (1981). A survey diagnostic tool for senile dementia. American Journal of Epidemiology, 114(4), 515–527. https://doi.org/10.1093/oxfordjournals.aje.a113217
• Pfeffer, R. I., Kurosaki, T. T., Chance, J. M., Filos, S., & Bates, D. (1984). Use of the Mental Function Index in older adults: Reliability, validity, and measurement of change over time. American Journal of Epidemiology, 120(6), 922–935. https://doi.org/10.1093/oxfordjournals.aje.a113963
• Teng, E., Becker, B. W., Woo, E., Cummings, J. L., & Lu, P. H. (2010). Utility of the Functional Activities Questionnaire for evaluating mild cognitive impairment and dementia in normal aging. The American Journal of Geriatric Psychiatry, 18(9), 779–787. https://doi.org/10.1097/JGP.0b013e3181cf869b

13. Items of the Scale (Questionnaire)