International Journal of Undergraduates Studies, 2(2),6-12,2013 ISSN: 2289-4242 6 ANALYSING EEG ALPHA BRAINWAVE SIGNAL ACTIVITIES BASED ON VISUAL STIMULATION Iza Sazanita Isa, Balkis Solehah Zainuddin, Zakaria Hussain and Nurul Huda Ishak Universiti Teknologi MARA, Malaysia ABSTRACT A current conceptual studies and researches are focusing on rehabilitation of SCI (Spinal Cord Injury) and stroke sufferer by using FES (Functional Electrical Stimulation) induced. The amount of FES induced is depending on level of injury and the muscle since the electrical stimulate is only in µvolt. To have sufficient amount of FES stimulation, the brain signal that transmit to muscle movement is the main controller of the body. Therefore, this study is conducted to measure brainwave signal of alpha wave electrical activity and observed the effect on visual stimulation of alpha wave on healthy normal brain. The brainwave signals measured from scalp using surface electrodes and EEG (Electroencephalograph) to detect the brain activities based on visual stimulation. From the analyzing results, it indicates that alpha waves during periods of eyes closed are the strongest EEG brain signal. Alpha waves is the most suitable signals to be integrated for FES stimulation as it consistency in producing electrical brainwave signals The findings of this conceptual study can be recommended to be implemented to control amount of FES induced based on physical activities specifically for stroke rehabilitation therapy. Keywords: EEG; brainwaves activities; alpha wave; FES INTRODUCTION The number of existing neurons in human brain cortex which being activated in synchronize patterns are resulting in certain rhythmic behavior. The potential stimulation produced in brain cortex is recordable with the recommended electrodes position on the skull. The potential patterns occur due to electrical rhythms and transient discharge represents in electroencephalogram (EEG). EEG signals can be classified based on skull positions, frequency ranges, amplitudes, signal waveforms, periods and signal-induced actions. Basically, the EEGs signals are synchronize when the external stimulated has been measured. The EEGs are affected due to different degree of alertness as example the separate sleeping periods result in different EEG characteristics. There are several techniques proposed by Do et al., (2011), Domino et al., (2009) and Jacobs & Friedman, (2004) in integration the EEG and FES and the challenging of EEG signals mainly due to its small amplitude. The EEG signal passes through dura, cerebrospinal fluid and skull to scalp will produces peak-to-peak amplitude is only about 1 ~ 100μV with frequency range 0.5 ~ 100 Hz. In addition, the electrode material, contact tightness and electrode paste may even affect the recordings due to some unpredictable noise which interfere with EEG detection. Brain waves are measured in cycles per second or Hertz (Hz) also known as frequency of brain wave activity. The lower number of frequency indicates that the slower the brain activity or the slower the frequency of the activity. The study from Teplan, (2002) has been categorized brain waves signal into four basic groups as shown in Table 1. Table I. Brainwave signal with dominant frequency band Brainwaves Frequency (Hz) Beta (β) Alpha (α) Theta (θ) Delta ( δ) >13 8 – 13 4 – 8 0.5 – 4 The objective of this study is to measure an alpha wave electrical activity and observed the effect on visual stimulation of alpha wave for healthy normal brain signal. This is the motivation to conduct this research brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Universiti Teknologi MARA Institutional Repository