Is There a Place for Clinical Neurophysiology Assessments in Synucleinopathies?

Abstract

IntroductionParkinson Disease (PD), Dementia with Lewy Bodies (DLB) and Multiple System Atrophy (MSA) are characterized by deposition of Lewy Bodies (LB), consisting of eosinophilic intracellular (intraneural in PD and DLB and intraglial in MSA) inclusions of -synuclein and allowing the three disorders to be categorized as synucleinopathies. The identification in the last two decades of specific clinical features of synucleinopathies has been a major breakthrough in Neurology, as it prompted a reconsideration of diagnostic and therapeutic approaches to dementia and parkinsonism. The recognition of synuclein and ubiquitin markers in dementia resulted in the reclassification of patients previously considered as affected by Alzheimer Disease (AD) and Vascular Dementia (VaD), and there is now agreement that DLB is the second most common cause of dementia in elderly population: its prevalence is reported to be in the 25-43% range in different studies. DLB is clinically characterized by the presence of prominently dysexecutive dementia (frontal lobe or subcortical dementia according to earlier classification [1]), cognitive fluctuations, consisting of remitting-relapsing episodes of blunted conscience reaching levels of stupor, by the occurrence of visual hallucinations and delusions, by parkinsonian motor signs and hypersensitivity to neuroleptic treatment, ranging from worsening of parkinsonism to the possible lethal neuroleptic-malignant syndromes [2]. Yet, variances of presentation and overlapping symptoms with AD and Fronto-Temporal lobe Degeneration (FTD), could be misleading in the process of addressing a clinical diagnosis with consequent therapeutic risks(e.g. introducing neuroleptic treatments in patient with DLB), or economic costs (e.g. addressing patients with DLB to treatment protocols dedicated to AD patients, based on vaccines or antibodies against amyloid proteins, a neuropathological feature of AD). It is evident the stringent need for improvement of reliable diagnostic tools (u.e. biomarkers) to differentiate the diseases associated with dementia. In 2010 the National Institute of Health, NIH, held a symposium focused on the development of possible biomarkers for DLB. Among the different suggested biomarkers, neurophysiological assessments were reconsidered, as a large amount of neurophysiological studies had been devoted to AD and PD, whose characteristics are shared by DLB. www.intechopen.com Neuroimaging for Clinicians -Combining Research and Practice 300We contributed to several studies on this argument along the years, and in the present chapter we discuss the role of clinical neurophysiological studies in DLB in comparison with other disorders. The essential background of our original studies laid in the fact that most historical studies were performed when the DLB clinical entity was unknown and therefore some of the past results were marred by absent recognition of this clinical entity. Synucleinopathies: Dementia with lewy bodiesSynucleinopathies comprise a diverse groups of neurodegenerati...