The diagnostic accuracy of the AD8 informant questionnaire for cognitive impairment was assessed in patients referred to a dedicated memory clinic. This pragmatic prospective study of consecutive referrals attending with an informant who completed AD8 (n = 212) lasted 12 months. Diagnosis used standard clinical diagnostic criteria for dementia and mild cognitive impairment as reference standard (prevalence of cognitive impairment = 0.62). The AD8 proved acceptable to informants, was quick, and easy to use. Using the cutoff of ≥2/8, AD8 was highly sensitive (0.97) for diagnosis of cognitive impairment but specificity was poor (0.17). Combining AD8 with either the Mini-Mental State Examination or the Six-Item Cognitive Impairment Test showed little additional diagnostic benefit. In conclusion, AD8 is very sensitive for cognitive impairment in a memory clinic but specificity may be inadequate.
GalvinJERoeCMCoatsMAMorrisJC. Patient’s rating of cognitive ability: using the AD8, a brief informant interview, as a self-rating tool to detect dementia. Arch Neurol. 2007;64
(5):725–730.
5.
DongYPangWSLimLBThe informant AD8 is superior to participant AD8 in detecting cognitive impairment in a memory clinic setting. J Alzheimers Dis. 2013;35
(1):159–168.
6.
ChinRNgANarasimhaluKKandiahN. Utility of the AD8 as a self-rating tool for cognitive impairment in an Asian population. Am J Alzheimers Dis Other Demen. 2013;28
(3):284–288.
7.
CarpenterCRDesPainBKeelingTNShahMRothenbergerM. The Six-Item Screener and AD8 for the detection of cognitive impairment in geriatric emergency department patients. Ann Emerg Med. 2011;57
(6):653–661.
8.
RyuHJKimHJHanSH. Validity and reliability of the Korean version of the AD8 informant interview (K-AD8) in dementia. Alzheimer Dis Assoc Disord. 2009;23
(4):371–376.
9.
YangYHGalvinJEMorrisJCLaiCLChouMCLiuCK. Application of AD8 questionnaire to screen very mild dementia in Taiwanese. Am J Alzheimers Dis Other Demen. 2011;26
(2):134–138.
10.
CorreiaCCLimaFJungueiraFAD8-Brazil cross-cultural validation of the ascertaining dementia interview in Portuguese. J Alzheimers Dis. 2011;27
(1):177–185.
11.
Carnero PardoCde la Vega CotareloRLopez AlcladeSAssessing the diagnostic accuracy (DA) of the Spanish version of the informant-based AD8 questionnaire. Neurologia. 2013;28
(2):88–94.
12.
RazaviMToleaMIMargrettJComparison of 2 informant questionnaire screening tools for dementia and mild cognitive impairment: AD8 and IQCODE. Alzheimer Dis Assoc Disord. 2014;28
(2):156–161.
13.
SackettDLHaynesRB. The architecture of diagnostic research. In: KnottnerusJA, ed. The Evidence Base of Clinical Diagnosis. London: BMJ Books; 2002:19–38.
14.
FolsteinMFFolsteinSEMcHughPR. “Mini-Mental State.” A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res. 1975;12
(3):189–198.
15.
BrookePBullockR. Validation of a 6 item cognitive impairment test with a view to primary care usage. Int J Geriatr Psychiatry. 1999;14
(11):936–940.
16.
LarnerAJ. Dementia in Clinical Practice: A Neurological Perspective. Pragmatic Studies in the Cognitive Function Clinic. 2nd ed. London: Springer; 2014.
17.
Noel-StorrAHMcCleeryJMRichardEReporting standards for studies of diagnostic test accuracy in dementia: the STARDdem Initiative. Neurology. 2014;83
(4):364–373.
18.
CohenJ. A coefficient of agreement for nominal scales. Educ Psychol Meas. 1960;20
(1):37–46.
19.
MoonsKGStijnenTMichelBCApplication of treatment thresholds to diagnostic-test evaluation: an alternative to the comparison of areas under receiver operating characteristic curves. Med Decis Making. 1997;17
(4):447–454.
20.
MallettSHalliganSThompsonMCollinsGSAltmanDG. Interpreting diagnostic accuracy studies for patient care. BMJ. 2012;345:e3999.
21.
LarnerAJ. Comparing diagnostic accuracy of cognitive screening instruments: a weighted comparison approach. Dement Geriatr Cogn Disord Extra. 2013;3
(1):60–65.
22.
CohenJ. Statistical Power Analysis for the Behavioral Sciences. 2nd ed. Hillsdale, NJ: Lawrence Erlbaum; 1988.
FlickerLLogiudiceDCarlinJBAmesD. The predictive value of dementia screening instruments in clinical populations. Int J Geriatr Psychiatry. 1997;12
(2):203–209.
25.
HancockPLarnerAJ. Diagnostic utility of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) and its combination with the Addenbrooke’s Cognitive Examination-Revised (ACE-R) in a memory clinic-based population. Int Psychogeriatr. 2009;21
(3):526–530.
26.
LarnerAJ. Screening utility of the Montreal Cognitive Assessment (MoCA): in place of—or as well as—the MMSE?Int Psychogeriatr. 2012;24
(3):391–396.
27.
LandisJRKochGG. The measurement of observer agreement for categorical data. Biometrics. 1977;33
(1):159–174.
28.
LarnerAJ. Optimizing the cutoffs of cognitive screening instruments in pragmatic diagnostic accuracy studies: maximizing accuracy or the Youden index?Dement Geriatr Cogn Disord. 2015;39
(3-4):169–175.
29.
ChristensenKJ. The impact of dementia prevalence on the utility of the AD8. Brain. 2012;135
(pt 1):e203.
30.
LarnerAJ. Screening utility of the “attended alone” sign for subjective memory impairment. Alzheimer Dis Assoc Disord. 2014;28
(4):364–365.
31.
SteenlandKMacneilJBartellSLahJ. Analyses of diagnostic patterns at 30 Alzheimer’s disease centers in the US. Neuroepidemiology2010;35
(1):19–27.
32.
DongYChengTSTsouKYChanQLChenCL. Feasibility and acceptability of the informant AD8 for cognitive screening in primary healthcare: a pilot study. ScientificWorldJournal. 2014;2014:302834.
