Meistaravörn við tækni- og verkfræðideild - Rún Friðriksdóttir

Cortical- and kinematic response during adaptation and habituation in human upright posture, using HD-EEG

  • 11.1.2019, 14:00 - 16:00

Rún Friðriksdóttir  will defend her masters thesis on january 11th, room M105 at 14:00. 

Title: Cortical- and kinematic response during adaptation and habituation in human upright posture, using HD-EEG

Committee:  

Dr. Paolo Gargiulo, Supervisor
Associate Professor, Biomedical Technology Centre, Reykjavík University

Dr. Hannes Petersen, Co-advisor
Professor, Department of Anatomy, University of Iceland

Examiner:

Dr. Elías Ólafsson, Examiner
Professor and Chairman, Department of Neurology, University of Iceland,

 

Abstract

Postural control in humans is naturally unstable and is considered to be a complex motor skill derived from the interaction of multiple sensori motor processes to maintain postural orientation and postural equilibrium. The objective of the present work is to quantify changes in cortical activity during human upright posture that correlate with the mechanical body sway performance.

Proprioceptive vibratory stimulation on calf muscles at 85 Hz was performed on 33 healthy subjects to evoke postural perturbation in open-eye and closed-eye experimental trials. Trials included 30 seconds of perturbed upright stance and 300 seconds of random vibratory stimulation phases divided into four epochs of 75 second each, with the impulses synchronized to EEG recording, using a 256-channel EEG cap with the sampling rate of 1024 Hz. Channels that were shown to have statistically significant change in absolute power spectra variation were distinguished over six frequency bands (!, 0.5-3.5 Hz; ✓, 3.5-7.5 Hz; ↵, 7.5-12.5 Hz; #, 12.5-30 Hz; low $, 30-50 Hz; and high $, 50-80 Hz). Force and torque actuated by the feet were recorded by a force platform and sampled at 50 Hz. A fluctuation index was computed to determine postural performance during the epochs. There was a significant correlation between progress in platform oscillations and changes in cortical activity. The fluctuation indices indicated improvement in postural performance. A significant increase was found in absolute power values, particularly in the parietal regions across alpha and theta bands during open-eye adaptation trials, and in gamma band during open- and closed-eye adaptation trials. To our knowledge, this is the first study to demonstrate correlation of platform oscillations and cortical activity using 256 channel EEG recordings.