Comment on "Motor Signs and Incident Dementia With Lewy Bodies in Older Adults With Mild Cognitive Impairment"

OpenAlex İngilizce

Identifying dementia with Lewy bodies (DLB) early on is still one of the most difficult problems. Liampas et al. shed light on an important piece of this puzzle by examining motor signs in older adults with mild cognitive impairment (MCI), and their predictive role in the development of DLB [1]. Their study highlighted the importance of early motor findings, such as masked facies, resting tremor, and bradykinesia, but its clinical applicability raises important questions about the appropriateness of current DLB diagnostic criteria [2, 3], the potential for depression to mimic DLB, and the confounding effect of drug-induced Parkinsonism. Especially, the clinical overlap related to motor symptoms between DLB and Parkinson disease dementia is well known, causing some diagnostic challenges. Addressing these issues is essential for refining the early identification of older adults with MCI who are at a high risk of DLB. Early diagnosis of DLB is notoriously challenging because of its heterogeneous clinical presentation [4]. Current consensus criteria emphasize core features such as Parkinsonism, fluctuating cognition, recurrent visual hallucinations, and rapid eye movement sleep behavior disorder [2]. Parkinsonism in DLB usually develops later, often following cognitive and neuropsychiatric symptoms. There is considerable overlap in clinical presentation between Parkinson's disease dementia (PDD), with which DLB is most often confused, and this similarity is distinguished primarily by the temporal sequence. The timing of dementia relative to Parkinsonism is the most important clinical distinction between DLB and PDD [5]. Patients who develop dementia within 1 year of the onset of motor signs are classified as having DLB [2]. In this study, patients with MCI and motor dysfunction were followed up for an average of 3.7 years; during this period, some of the patients were diagnosed with DLB. Considering the Parkinsonism findings and follow-up period of the patients in the study, the diagnosis of DLB in patients followed for more than 1 year may not be appropriate for the temporal order [2]. However, this 1-year rule is difficult to apply in clinical follow-up. In line with this, the study by Liampas et al. carries remarkable results for future studies, as it shows that motor symptoms can be seen more than 1 year before dementia. A particularly important challenge is the overlap of DLB and late-life depression. Depression in older adults often presents with psychomotor slowing, reduced facial expression, and apathy symptoms that closely resemble those of early DLB [6]. It is not clear from this study whether standardized neuropsychiatric assessments were used to differentiate depression-related motor slowing from true Parkinsonian signs. Without a structured assessment, there is a risk that some individuals classified as having prodromal DLB may instead have a depressive syndrome with motor slowing [7]. Future research should include validated depression screening tools and longitudinal follow-up to improve diagnostic accuracy. Additionally, the well-documented neuroleptic sensitivity of patients with DLB remains an underexplored factor in this study [8]. Exposure to dopamine blocking agents can significantly worsen motor symptoms and cognitive decline in DLB, but the study does not provide clarity on the participants' prior medication use. This is particularly important as the high prevalence of sleep disorders in older adults has led to increased prescription of sedatives and antipsychotics, many of which have dopamine blocking properties [9]. Without careful documentation of medication history, it is difficult to determine whether the observed Parkinsonian signs reflect the true progression of DLB or are in part drug-induced effects [10]. Future studies should systematically account for prior exposure to neuroleptics and sedatives when analyzing early motor predictors of DLB. This study represents an important step towards improving the early detection of DLB. However, the timing of the development of Parkinsonism in DLB remains a controversial issue. Furthermore, consideration of depressive motor slowing and medication-induced Parkinsonism may be important in improving the diagnostic process of DLB. Future research should prioritize prospective studies that include comprehensive neuropsychiatric assessments and medication history to improve the diagnostic specificity. Ultimately, improving the early diagnosis of DLB is not just a clinical achievement; it is essential to ensure that patients receive timely and appropriate care, minimizing misdiagnoses and the associated risks of inappropriate treatment. Neziha Erken: concept, design, writing, and preparation of the letter. Dilara Erdem: concept, design, writing, and preparation of the letter. Mehmet Ilkin Naharci: concept, design, writing, and preparation of the letter. The authors declare no conflicts of interest. This publication is linked to a related reply by Liampas and Dardiotis. To view this article, visit https://doi.org/10.1111/jgs.19543.