AUTHOR=Lithgow Brian J. , Moussavi Zahra 

TITLE=Measuring anxiety disorder in bipolar disorder using EVestG: broad impact of medication groups

JOURNAL=Frontiers in Neurology

VOLUME=Volume 14 - 2023

YEAR=2024

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1303287

DOI=10.3389/fneur.2023.1303287

ISSN=1664-2295

ABSTRACT=Objectives: Anxiety disorder is present in about half of all Bipolar Disorder (BD) patients. There are neurologic bases for the comorbidity of balance (vestibular) disorders and anxiety. Our objective is to use Electrovestibulography (EVestG), which is predominantly a measure of vestibular neural activity, to not only quantitatively detect and measure comorbid anxiety disorder, but also to quantitatively measure the impacts of anti-depressant, anti-psychotic and mood stabilizer medication groups on anxiety measures in BD patients. 
Methods: In a population of 50 (24 with anxiety disorder) depressive phase BD patients, EVestG signals were measured. Participants were depression-wise labelled as anxious or non-anxious using standard questionnaires. Analyses were conducted on the whole data set as well as matched (age/gender/MADRS) and ‘modelled medication free’ subsets. Modulations of the low frequency EVestG firing pattern data were measured. 
Findings: For BD the main anxious minus non-anxious difference was the presence of an increase in spectral power proximal to 8-9Hz which was best attenuated by mood stabilizers.
 Novelty: This is the first study to use an oto-acoustic physiogical measure to quantify Anxiety disorder in BD wherein it appears to manifest as a peak proximal to 8-9Hz which we hypothesize as likely linked to Hippocampal Theta.