Question

Question Posted 09/23/14:
Dear ADNI scientist,

We have finished a multivariate mapping of brain atrophy signature in the ADNI cohort. As a post-hoc analysis, we have decided to investigate how the regional brain atrophy pattern changes in AD as the disease progresses. For this, a variable showing relative duration of Alzheimer's disease in the demented subjects is needed (the time span between either the first cognitive impairment symptoms or AD diagnosis, and MRI day)

Regarding this, we have found three relevant variables in the patient demographic table, and based on brief descriptions of the data dictionary we have guessed that:

ADBEG (ADNI-1/GO) : the year of establishing Alzheimer's diagnosis (?) or appearance of first Alzheimer's disease symptom (?)

MCIBEG (ADNIGO): Year of first cognitive impairment symptoms

COGBEG (ADNI-2): Year of first cognitive impairment symptoms

We have few questions regarding these records;

1- It seems that COGBEG and MCIBEG are similar in most subjects (few exceptions). Do these two variables represent similar memory impairment criteria in general?

2- Does the ADBEG record represent date of fulfilling an Alzheimer's disease diagnosis?

3- demented subjects in ADNI-1 cohort lack the COGBEG record. Is there any chance to gain cognitive impairment onset data regarding these individuals? (for comparison purpose with ADNI-GO/2). If not, what common disease onset metric is available in all ADNI-1/GO/2 cohorts for having an insight into disease duration in demented individuals across the whole study phases? (since, in the other hand, ADNI-2/GO subjects lack ADBEG record.)

Thank you in advance,
Sourena Soheili-Nezhad, M.D.
Response posted 09/24/14 by Mike Weiner (By KC):
1- It seems that COGBEG and MCIBEG are similar in most subjects (few exceptions). Do these two variables represent similar memory impairment criteria in general?  YOU CAN JUDGE THIS AS BEST AS I CAN

2 Does the ADBEG record represent date of fulfilling an Alzheimer's disease diagnosis?  ITS VERY HARD TO KNOW THIS, MOST OF THIS INFORMATION COMES FROM THE SUBJECT OR THE INFORMANT, IN SOME CASES THE SUBJECT MIGHT HAVE BEEN A PATIENT AT THE CENTER WHERE THEY WERE ENROLLED IN ADNI BUT OTHER SUBJECTS MIGHT BE COMING FROM OTHER CENTERS.  WE DONT RECORD THAT INFORMATION

3 3- demented subjects in ADNI-1 cohort lack the COGBEG record. Is there any chance to gain cognitive impairment onset data regarding these individuals?  NO   (for comparison purpose with ADNI-GO/2). If not, what common disease onset metric is available in all ADNI-1/GO/2 cohorts for having an insight into disease duration in demented individuals across the whole study phases? (since, in the other hand, ADNI-2/GO subjects lack ADBEG record.)  ADAS COG,  MMSE,  CDR