Clinical Utility of the Envelope Task in Mild Cognitive Impairment and Dementia.
OBJECTIVE
Prospective memory (PM) is a cognitive function defined as the ability to perform an intention at an appropriate moment in the future. In the aging population, PM is essential for maintaining independent daily living. Introduced as a simple and quick way to assess PM in clinical settings, the envelope task has to date received very limited empirical and practical interest.


METHODS
The present study investigated the task's clinical utility in detecting PM impairment in a sample composed of 49 healthy older adults (OA), 41 patients with Alzheimer's disease, and 64 individuals with amnestic and nonamnestic mild cognitive impairment (MCI) of heterogeneous etiology: 17 of idiopathic nature, 20 presenting an idiopathic rapid-eye movement sleep behaviour disorder, and 27 patients diagnosed with idiopathic Parkinson's disease.


RESULTS
The envelope task was highly sensitive and specific in discriminating Alzheimer's disease patients from OA. Although it was specific in distinguishing MCI individuals from OA, its sensitivity was modest, especially in patients presenting a nonamnestic MCI subtype.


CONCLUSIONS
Given its high specificity and simple low-cost administration procedure, the envelope task is a promising instrument for clinicians who seek to rapidly assess PM impairment in their daily practice.
1Department of Psychology,Université du Québec à Montréal,Montreal,Quebec,Canada.
Sonia
S
Marcone
1Department of Psychology,Université du Québec à Montréal,Montreal,Quebec,Canada.
Jean-François
JF
Gagnon
1Department of Psychology,Université du Québec à Montréal,Montreal,Quebec,Canada.
Sarah
S
Lecomte
3Clinique de mémoire,Institut universitaire de gériatrie de Sherbrooke,Sherbrooke,Quebec,Canada.
Hélène
H
Imbeault
1Department of Psychology,Université du Québec à Montréal,Montreal,Quebec,Canada.
Frédérique
F
Limoges
2Center for Advanced Research in Sleep Medicine,Hôpital du Sacré-Coeur de Montréal,Montreal,Quebec,Canada.
Ronald B
RB
Postuma
1Department of Psychology,Université du Québec à Montréal,Montreal,Quebec,Canada.
Josie-Anne
JA
Bertrand
5Institut universitaire de gériatrie de Montréal,Montreal,Quebec,Canada.
Sven
S
Joubert
1Department of Psychology,Université du Québec à Montréal,Montreal,Quebec,Canada.
Isabelle
I
Rouleau
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis*; D060825:Cognitive Dysfunction / Q000175:diagnosis*; D003704:Dementia / Q000175:diagnosis*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D008609:Mental Status Schedule; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000175:diagnosis; D020187:REM Sleep Behavior Disorder / Q000175:diagnosis; D012372:ROC Curve
Aging; Alzheimer’s disease; Executive Function; Mild Cognitive Impairment; Neurodegenerative Disorders; Neuropsychology; Parkinson Disease; Prospective Memory; REM Sleep Behaviour Disorder