Repetitive Behaviors in Alzheimer's Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Repetitive behaviors (RBs) are a well-known symptom of Alzheimer's disease (AD); however, they have been little studied and have not been the subject of any specific literature review. OBJECTIVE: To conduct a systematic review of all studies to document RBs in AD. METHODS: An extensive literature search combining five databases and a meta-analysis were conducted to investigate the frequency, nature, and cognitive correlates of RBs in AD. RESULTS: Ten studies were included in the review. Seven studies out of ten investigated the frequency of RBs in patients with AD, which ranged from 52.3% to 87%. A meta-analysis showed an overall frequency of 66.3% (95% CI: 55.5; 77.1) of patients exhibiting RBs in AD, but important heterogeneity was observed between studies. Three studies investigated the predominant nature of RBs in AD. Verbal RBs, complex behavioral stereotypies, and simple motor stereotypies have been identified to different degrees depending on the level of dementia. Most verbal RBs are underpinned by episodic memory impairment, while simple motor stereotypies and complex behavioral stereotypies are mostly underpinned by executive dysfunction. CONCLUSIONS: The current review seems to suggest that there are two types of mechanisms underpinning RBs involved in AD. The first is observed especially in the mild stages of the disease and is mediated by episodic memory impairment. The second occurs later and is mediated by executive impairment. Additional studies should be conducted to improve the knowledge about RBs in AD and thus improve their management.Systematic review registration number: PROSPERO 2022: CRD42022310027.

The relationship between semantic and episodic memory: evidence from a case of severe anterograde amnesia.

It is increasingly being recognized that new declarative, consciously accessible information can be learned in anterograde amnesia, but it is not clear whether this learning is supported by episodic or semantic memory. We report a case of a 55-year-old man who experienced severe amnesia after limited damage to the medial temporal lobe following neurosurgical complications. His general cognitive performance and knowledge of new French words and public events that occurred before and after the onset of amnesia were assessed. Performance remained satisfactory on post-morbid vocabulary and public events, with a drop in performance observed for very recent public events only, while knowledge of very recent vocabulary was comparable to that of the control subjects. The implications of these findings for our understanding of the underlying learning mechanisms are discussed. This is the first report of acquisition of consciously accessible postmorbid knowledge of public events in a patient with severe amnesia.

Subjective cognitive complaints and relations to objective cognitive performance among Lebanese patients with schizophrenia.

BACKGROUND: Patients with schizophrenia have a particularly low level of insight into their illness compared to people with other mental health disorders. The objectives of the study were to evaluate: 1) subjective cognitive complaints in individuals with schizophrenia in comparison with health controls, 2) the relation between subjective cognitive complaint (SCC) and objective cognitive performance in the patients group, and 3) factors related to cognitive complaint, such as depression, insight, autonomy, and psychological symptoms. METHODS: Cross-sectional study was conducted between July 2019 and March 2020 enrolled 120 patients with schizophrenia disorders, selected from the Psychiatric Hospital of the Cross (HPC) - Lebanon and 60 healthy controls. The Self-Assessment Scale of Cognitive Complaints in Schizophrenia (SASCCS) was used to measure people living with schizophrenia perception of their cognitive impairment, while the Brief Assessment of Cognition in Schizophrenia (BACS) was used to evaluate their cognitive functioning. RESULTS: A significant difference was found between schizophrenia patients and healthy controls in all neurocognition and SASCCS tests. The hierarchical regression analysis showed that the BACS total score (Beta = -.06, p = .04), the PANSS general psychopathology (Beta = .29, p = .003), higher depression (Beta = .75, p = .003) were significantly associated with higher SCC. However, higher autonomy (Beta = - 6.35, p = .001) was significantly associated with lower SCC. A Structural equation model showed that the two most contributing variables were general psychopathology (Standardized Beta (SB): .33, p < 0.001) and autonomy (SB: -.29, p < 0.001). CONCLUSION: A significant proportion of patients with schizophrenia could estimate their cognitive impairment. It also showed a positive correlation between depression and activity of daily living with SCC, suggesting that this aspect should be investigated alongside the clinical symptoms when a patient with schizophrenia presents with SCC.