Comparative Analysis of White Matter Signal Alterations in Dementia with Lewy Bodies (DLB) and Alzheimer's Disease (AD): A Systematic Review and Meta-Analysis

Asad Abdi ¹ Milad Alipour ² Milad Ghanikolahloo ³ Fatemeh HojjatiPour ⁴ Ali Gholamrezanezhad ⁵ Mehran Ilaghi ⁶ Mehran Anjomrooz ⁷ Fatemeh Sayehmiri ⁸ Ramtin Hajibeygi ⁷ Mobina Fathi ^4* REZA ASSADSANGABI ^5*

• ¹ Rheumatology Unit, Dubai Hospital, Dubai, United Arab Emirates
• ² Department of Medicine, Islamic Azad University of Medical Sciences, Tehran, Alborz, Iran
• ³ King's College Hospital NHS Foundation Trust, London, England, United Kingdom
• ⁴ Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Alborz, Iran
• ⁵ University of California, Los Angeles, Los Angeles, California, United States
• ⁶ Institute of Neuropharmacology, Kerman Neuroscience Research Center, Kerman University of Medical Sciences, Kerman, Kerman, Iran
• ⁷ Advanced Diagnostic and Interventional Radiology Research Center, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Alborz, Iran
• ⁸ Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Alborz, Iran

Background and Aim: Lewy body diseases (LBD) include neurodegenerative diseases such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and Parkinson's disease dementia (PDD). Because DLB and Alzheimer's disease (AD) share similar neurological symptoms, DLB is frequently underdiagnosed. White Matter Hyperintensities (WMH) is are associated with dementia risk and changes in both DLB and AD. In order to examine WMH discrepancies in DLB and AD patients and gain insight into their diagnostic utility and pathophysiological significance, this systematic review and meta-analysis is conducted. Material and Methods: Databases such as PubMed, Scopus, Google Scholar, and Web of Science were searched for studies reporting WMH in DLB and AD patients based on Preferred Reporting Items for Systematic Review (PRISMA) guideline. Stata version 15 US is used to analyze the extracted data.Results: Twelve studies with 906 AD and 499 DLB patients were considered in this analysis. Although not statistically significant, the WMH was 0.03 ml larger in AD patients than in DLB patients. The prevalence of hypertension varied, ranging from 21% to 56% in DLB patients and from 30% to 52% in AD patients. Different findings were found on the prevalence of diabetes; some research suggested that DLB patients had greater rates (18.7% to 37%) than AD patients (9% to 17.5%). In comparison to controls, WMH levels were generally higher in both groups, with DLB patients showing a larger total WMH volume. The imaging modalities FLAIR, T2-weighted, and T1-weighted sequences were employed. Compared to DLB patients, AD patients had higher cortical and infratentorial infarcts. Conclusion: Those with AD have greater WMH volumes than cases with DLB, suggesting that WMH can be a biomarker to help better differentiation between these neurodegenerative diseases; however, this difference is not significant. To better understand the therapeutic implications and options for reducing WMH-related cognitive loss in various patient populations, more research is necessary.