Behavioral and psychological symptoms in the preclinical stage of Alzheimer's disease

Abstract

Background: AD is preceded by a lengthy preclinical period. Neural degeneration may lead to the appearance of behavioral and psychological symptoms, even before other clinical symptoms are manifest. We attempted to evaluate this symptomatology in preclinical AD.

Material/methods: We recruited 291 care center residents who did not demonstrate dementia symptoms according to DSM-IV, whose MMSE score was at least 24, and who reached the first or second stage on the Global Deterioration Scale. Psychopathology was assessed using the AMDP, while the ADAS-cog was used to assess cognitive dysfunctions. Seven years later, 155 patients participated in the follow-up study (MMSE and ADAS-cog). If the MMSE was less than 24, a psychiatric workup was done to verify dementia. The AD group consisted of persons properly diagnosed with AD (n=25), while the control group consisted of persons in whom dementia had not developed.

Results: The AD and control groups differed in the level of psychopathological symptoms at baseline. The disparities related both to the global AMDP score and to every particular symptom category. The analysis did not disclose a pathognomonic symptom for preclinical AD, but there were many symptoms whose intensity differentiated AD patients from the controls. The degree of cognitive dysfunction seems to correlate with the clinical manifestation of some psychopathological symptoms in preclinical AD.

Conclusions: The degeneration process before the clinical manifestation of dementia leads not only to the impairment of several cognitive functions, but also the intensification of behavioral and psychological symptoms.