[Mild cognitive impairments in the elderly: a critical review].
The aging of the population leads to increased awareness of problems associated with age-related degenerative dementias. Given that these dementias are progressive in onset, many clinicians and researchers have proposed criteria that allow for the identification of older subjects manifesting cognitive impairment, but not responding to the criteria for dementia. Our knowledge of subjects with mild cognitive impairment is limited; it is, however, established that they present a high risk of developing dementia in the future. Although it is essential to increase our comprehension of their cognitive and functional decline, the study of subjects presenting mild cognitive impairment is compromised due to the existence of numerous non-converging classifications. The goal of the present article is to conduct a critical review of the different classifications of mild cognitive impairment in the elderly in order to attempt to identify the optimal criteria, allowing for a distinction to be made between subjects with mild cognitive impairment, who remain in a stable state and those whose condition evolves to a dementia. These criteria may enable us to describe a homogenuous group of individuals presenting with different rates of dementia risk factors. We present the classifications most frequently used in clinical and research settings. After listing them according to categorial, clinical or dimensional approaches, we performed a critical analysis for each one. Depending on the diagnostic criteria applied, major variations are revealed for the prevalence of cognitive impairment and the incidence of dementia. They are explained by methodological and theoretical shortcomings that we point out and discuss (e.g., reference group, lack of diagnostic criteria or exclusion criteria, high level of subjectivity). Beyond these criticisms, we discuss the challenges to be met in order to reach the optimal identification criteria. Notably, the impact of mild cognitive impairment on daily living activities should be tested with the use of more specific questionnaires/tasks. The goal of the objective definition of cognitive impairment should be to minimize subjectivity in the diagnosis. It is also suggested that sensitive cognitive measures would be used on all aspects of cognition, while recognizing and taking into account all confounding factors (e.g., age, education level). Given the nature and consequences of mild cognitive impairment, an inter-disciplinary approach is suggested (e.g., neurobiological, psychiatric, and genetic cues). A consensus on optimal diagnostic criteria is essential to propose cognitive and pharmacological treatments for the effective prevention of ementia.
Blanchet
S
S
Centre de Recherche, Institut Universitaire de Gériatrie de Montréal, 4565, Chemin Queen-Mary, Montréal H3W 1W5, Canada. sophie.blanchet@umontreal.ca
McCormick
L
L
Belleville
S
S
Gély-Nargeot
M C
MC
Joanette
Y
Y
D000367:Age Factors; D000368:Aged; D000375:Aging; D003072:Cognition Disorders / Q000145:classification / Q000175:diagnosis; D006801:Humans; D012720:Severity of Illness Index
Les troubles cognitifs légers de la personne âgée: revue critique.