Student

• Deborah Cecelia Rose Jacob

Supervisor

• Paolo Gargiulo, Professor School of Engineering at Reykjavik University and of Director Inst. f. Biomed. and Neural Engineering/ Med. Technology Centre 

Committee

• Hannes Petersen, Professor School of Medicine University of Iceland
• Giorgio Di Lorenzo MD, Associate Professor of Psychiatry at University of Rome Tor Vergata Rome, Italy
• Dr. María Kristín Jónsdóttir, Professor School of Psychology at Reykjavik University, Iceland

Examiner

• Leandro Pecchia, Professor of Biomedical Engineering, Campus Biomedico Rome, Italy

Title

Assessing Neurophysiological Conditions using a Multimetric Approach (BioVRSea paradigm)

Abstract

Current diagnosis and longitudinal evaluation of many neurological disorders rely on subjective, questionnaire-based approaches rather than measured biomarkers of the disease. Deficits of postural control are frequently seen in such diseases and provide a route for more objective assessment. This thesis reports the work completed using the unique BioVRSea setup to assess those with a history of concussion and those with early-stage Parkinson’s Disease and using a combination of neurophysiological (electromyography - EMG, electroencephalography - EEG, heart rate) and centre of pressure (CoP) measurements. The BioVRSea experiment is a challenging postural control task triggered by a moving platform and a virtual reality environment, during which the neurophysiological measurements are taken.

In the first paper, measurements were performed on 54 professional athletes who self-reported their history of concussion or non-concussion. Biosignals and CoP parameters were analyzed before and after the platform movements, to compare the net response of individual postural control. The results showed that BioVRSea discriminated between the concussion and non-concussion groups. Particularly, EEG power spectral density in delta and theta bands showed significant changes in the concussion group and right soleus median frequency from the EMG signal differentiated concussed individuals with balance problems from the other groups. Anterior–posterior CoP frequency-based parameters discriminated concussed individuals with balance problems.

In the second study on Parkinson’s Disease, 11 early-stage Parkinson’s subjects and 46 healthy over-50s took part in the experiment. Significant differences were found between the two groups in electromyographic and centre of pressure measurements. Correlation analysis of the EMG signal indicated opposite correlations in skewness in the right soleus muscle.

In the second Parkinson’s Disease study, 29 healthy and 9 early-stage Parkinson’s Disease subjects were assessed. The results of our work show significant differences in several biosignal features, particularly in the right tibialis anterior, the ellipse area associated with the centre of pressure changes and the power spectral density changes in the alpha and theta bands of the EEG.

This thesis shows the potential of BioVRSea as a quantitative means of developing a multi-metric signature capable of quantifying postural control and distinguishing healthy from pathological response.