A Longitudinal Multidimensional Population Study on Brain Aging (InveCeAb)

Background:

Dementia is one of the most troubling neurodegenerative syndrome whose prevalence and incidence is strongly increasing. The etiology and physiopathology of the process that causes dementia are still controversial and largely unknown. So it is of paramount importance to isolate risk and protection factors related to dementia syndrome and Alzheimer disease. These meager known factors (biological, as well as social and neuropsychological) can be better investigated through a multidimensional longitudinal study in a homogeneous population by age and place.

Method:

People belonging to the selected population (1773 subjects living in Abbiategrasso and born between 1935 - 1939) were invited to participate at a comprehensive assessment which was divided in two appointments:

• a first appointment (about 1 hour and half) for blood sample, social questionnaire, anthropometric and walking speed evaluation ;
• a second one (2 hours)for clinical examination and neuropsychological assessment of mood and cognitive function.

Recruitment. People were recruited through several steps:

• involvement of the family doctor;
• a general call, based on age group(1935,1936, 1937, 1938, 1939), since to be born in the same year is an identity mark for these generations;
• kick-off meetings for each age class explaining aims and methods of the research, followed by a party with music, plays and some lotteries
• a letter with the date of the appointment followed by the phone call whenever the phone number is available
• further letters and call until either a rejection or an appointment was taken.

Assessment. Professionals and instruments:

• Trained interviewers, one social worker and two nurses, administer the social questionnaire that is partly derived from the CERAD and from other longitudinal studies.
• Trained psychologists administer a neuropsychological battery exploring mood (GDS 15 items), verbal and visual memory (Rey 15-item Memory Test, and the Rey-Osterrieth Complex Figure Test (ROCF) recall; Babcock Story Recall Test ), executive function ( TMTA and TMTB; copy of ROCF), attention (Numerical Attention), abstract reasoning (Raven's Coloured Progressive Matrices), screening cognitive test (Clock test and MMSE).
• Clinical interview and visit are executed by expert geriatricians, members of the same geriatric staff who apply diagnostic criteria for dementia (DSM IV), Alzheimer disease (NINCDS ADRDA diagnostic criteria); Vascular dementia (NINDS -AIREN criteria); Lewy Body dementia (third report, DLB consortium); frontotemporal dementia ( 2002 modified Consensus conference criteria). Other cognitive problems were classified as Mild Cognitive Impairment (MCI) following Petersen's criteria or Cognitive Impairment No Dementia (CIND) when cognitive impairments are in areas other than memory and they do not meet whole criteria for dementia. Every diagnostic conclusion is revised by another doctor; in case of discrepancies a third geriatrician, chief of the study, intervenes to arbitrate.

All the instruments were pre tested for inter rater reliability in a similar population attending a geriatric day hospital, and some general agreement sessions were performed before and during the screening.