Dysautonomia in Alzheimer's Disease.

Delia Tulbă,Eugenia Irene Davidescu,Liviu Cozma,Bogdan Ovidiu Popescu

doi:10.3390/medicina56070337

Abstract

Alzheimer's disease is the most common neurodegenerative disorder, and its prevalence increases with age. Although there is a large amount of scientific literature focusing on Alzheimer's disease cardinal cognitive features, autonomic nervous system dysfunction remains understudied despite being common in the elderly. In this article, we reviewed the evidence for autonomic nervous system involvement in Alzheimer's disease. We identified four major potential causes for dysautonomia in Alzheimer's disease, out of which two are well-studied (comorbidities and medication) and two are rather hypothetical (Alzheimer's pathology and brain co-pathology). Although there appears to be some evidence linking Alzheimer's disease pathology to autonomic nervous system dysfunction, there is an important gap between two types of studies; histopathologic studies do not address dysautonomia manifestations, whereas clinical studies do not employ histopathologic diagnostic confirmation. Moreover, brain co-pathology is emerging as an important confounding factor. Therefore, we consider the correlation between dysautonomia and Alzheimer's disease to be an open question that needs further study. Nevertheless, given its impact on morbidity and mortality, we emphasize the importance of assessing autonomic dysfunction in patients with Alzheimer clinical syndrome.

Highlights

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide
There appears to be some evidence linking Alzheimer's disease pathology to autonomic nervous system dysfunction, there is an important gap between two types of studies; histopathologic studies do not address dysautonomia manifestations, whereas clinical studies do not employ histopathologic diagnostic confirmation
It has been suggested that dysautonomia might accelerate cognitive decline [13], and some authors even regard it as an early biomarker of neurodegeneration [12]

Summary

Introduction

Alzheimer's disease (AD) is the most common neurodegenerative disorder worldwide. Its prevalence increases with age, affecting 3% of people aged 65–75 and 32% of people older than 84 years, with further rise expected due to the “baby boomer” effect [1]. Over the past 30 years, evidence that ANS dysfunction develops in patients with AD and worsens with advanced disease has emerged [11]. It might occur before the onset of the clinical symptoms of dementia [12]. Found that dysphagia occurs in 84–93% of AD patients and affects both oral and pharyngeal stages, occasionally in early phases of the disease [14] They assumed that functional changes in the cortical swallowing network might be responsible for dysphagia and found a direct correlation between its severity and that of AD [14].

Dysautonomia as a Result of Alzheimer’s Disease Pathology

Dysautonomia as a Result of Brain Co-Pathologies

Dysautonomia as a Result of Comorbidities and Medication

Findings

Concluding Remarks