Systematic Review on the Role of Lobar Cerebral Microbleeds in Cognition

Article type: Systematic Review

Authors: Cipriano, Lorenzo^a | Saracino, Dario^b | Oliva, Mariano^a | Campana, Vito^a | Puoti, Gianfranco^a | Conforti, Renata^c | Fulgione, Ludovica^d | Signoriello, Elisabetta^a | Bonavita, Simona^a | Coppola, Cinzia^{a; *}

Affiliations: [a] Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, Naples, Italy | [b] Sorbonne Université, Paris Brain Institute - Institut du Cerveau (ICM), INSERM U1127, CNRS UMR 7225 – Aramis Project Team, Inria Research Center of Paris – Reference Center for Rare or Early Dementias, IM2A, Department of Neurology, AP-HP - Hôpital Pitié-Salpêtrière, Paris, France | [c] Department of Medicine of Precision, University of Campania “Luigi Vanvitelli”, Naples, Italy | [d] Department of Advanced Biomedical Sciences, University of Naples “Federico II”, Naples, Italy

Correspondence: [*] Correspondence to: Cinzia Coppola, MD, PhD, Second Neurological Clinic, University of Campania “Luigi Vanvitelli”, Isola 8, Edificio 10 Policlinico, “Federico II” via Pansini 5, 80131 Napoli, Italy. Tel.: +39 081 566 6811; Fax: +39 081 566 6805; E-mail: cinzia.coppola@unicampania.it; ORCID: 0000-0002-1125-6779.

Abstract: Background:Cerebral microbleeds (CMBs) are small round/oval lesions seen in MRI-specific sequences. They are divided in deep and lobar according to their location. Lobar CMBs (L-CMBs) are commonly associated with amyloid angiopathy. Although CMBs have been considered clinically silent for a long time, a growing body of evidence has shown that they could play a crucial role in cognitive functioning. Objective:The aim of this systematic review was to estimate the role of L-CMBs in cognitive performance. Methods:We selected, from the Cochrane Library, Embase, PubMed, and ScienceDirect databases, clinical studies, published from January 2000 to January 2020 and focused on the association between L-CMBs and cognitive functions. The inclusion criteria were: 1) participants grouped according to presence or absence of CMBs, 2) extensive neuropsychological examination, 3) CMBs differentiation according to topographical distribution, and 4) MRI-based CMB definition (< 10 mm and low signal in T2*/SWI). The impact of L-CMBs was separately assessed for executive functions, visuospatial skills, language, and memory. Results:Among 963 potentially eligible studies, six fulfilled the inclusion criteria. Four studies reported a greater reduction in executive performances in participants with L-CMB and two studies showed a statistically significant association between visuospatial dysfunction and L-CMBs. No association was found between hippocampal memory or language abilities and L-CMBs. Conclusion:Lobar CMBs are associated with a reduction of processing speed and visuospatial performances, thus suggesting the contribution of vascular amyloid deposition to this cognitive profile. This occurrence enables us to suspect an underlying Alzheimer’s disease pathology even in absence of typical hippocampal memory impairment.

Keywords: Alzheimer’s disease, cerebral microbleeds, cognitive impairment, executive functions, hippocampal memory

DOI: 10.3233/JAD-215323

Journal: Journal of Alzheimer's Disease, vol. 86, no. 3, pp. 1025-1035, 2022