Study of Repetitive Behaviors in Alzheimer's Disease

Alzheimer's disease (AD) is characterized by anterograde amnesia, the inability to memorize and remember events occurring after the cerebral lesion. Among the most frequently reported psychobehavioral symptoms are repetitive behaviors (RBs), defined as actions or statements repeated in an inappropriate and non-functional way. The most commonly used tool to assess repetitive behaviors is the Stereotypy Rating Inventory (SRI). It is a questionnaire that evaluates five types of stereotypical behavior: eating, wandering, speech, movements, and daily routines. The frequency and severity of the behaviors are reported, and a total score can be calculated. There is no consensus on the types of repetitive behaviors observed specifically in AD, their frequency, or their cognitive correlates, nor is there a hypothesis explaining why these symptoms do not occur in all AD patients. Furthermore, certain parameters, such as anosognosia (lack of awareness of the disorders), have not been linked to RBs in the literature. We propose to evaluate patients with anterograde amnesia in terms of cognition and behavior-specifically, the presence or absence of both RBs and anosognosia-to examine possible links between cognitive performance, anosognosia, and RB. Moreover, there is no theoretical framework explaining the emergence of RBs in amnesia. We suggest that RBs are linked to a lack of memory updating in the cognitive system. Since episodic memory no longer provides mnemonic feedback, previously encountered stimuli may trigger repeated behavior. To test this hypothesis, we decided to conduct a multicenter, cross-sectional, case-control study. Patients with AD, with or without RBs, as well as healthy subjects, were repeatedly presented with sentence starters to complete freely, with the aim of studying the similarity of responses across sessions for each participant. We also included a patient with pure anterograde amnesia from a previously submitted case study protocol, who exhibite