A memory complaint, also called Subjective Cognitive Decline (SCD), is a subjective disorder that appears to be relatively common, especially in elderly persons. The reports of its prevalence in various populations range from approximately 10% to as high as 88%, although it is generally thought that the prevalence of everyday memory problems lie within the range of 25% to 50%. It has been suggested that SCD may be an indication of cognitive decline at a very early stage of a neurodegenerative disease (i.e. preclinical stage of Alzheimer's disease) that is undetectable by standard testing instruments. SCD may represent the first symptomatic manifestation of Alzheimer's disease in individuals with unimpaired performance on cognitive tests.
The McNair and Kahn Scale or Cognitive Difficulties Scale was employed to define and characterize cognitive complaints in the GuidAge study, involving a population of more than 2800 individuals aged 70 years or older having voluntarily complained of memory problems to their general practitioner (GPs). It contains items that are related to difficulties in attention, concentration, orientation, memory, praxis, domestic activities and errands, facial recognition, task efficiency, and name finding.
The results of the GuidAge study suggest that the assessment of cognitive complaint voluntarily reported to primary-care physicians, by the McNair and Kahn scale can predict a decline in cognitive performance, as 5 items out of 20 were statistically significant.
These 5 items are:
- item 1, "I hardly remember usual phone numbers",
- item 5, "I forget appointment, dates, where I store things",
- item 6, "I forget to call people back when they called me",
- item 10, "I forget the day of the week",
- item 13, "I need to have people repeat instructions several times".