Effects of eyelid closure, blinks, and eye movements on the electroencephalogram.
OBJECTIVE
To characterize the effects of the eyeball and eyelid positions during eyeblinks on electroencephalographic (EEG) potentials.


METHODS
Movements of the upper eyelids and eyes were measured in two healthy subjects using the magnetic search coil technique during horizontal and vertical eye rotations, eyeblinks, and lid closure. Corresponding signal changes were recorded simultaneously on the electroencephalogram (EEG).


RESULTS
Spontaneous blinks produced small eye movements directed down and inward, whereas slow or forced blinks were associated with delayed upward eye rotations (i.e. Bell's phenomenon); both types of blinks caused positive EEG potentials with bifrontal distribution maximum at Fp1 and Fp2.


CONCLUSIONS
In prior reports, these positive EEG artifacts have been attributed to upward eyeball rotation during blinks-Bell's phenomenon. By contrast, our findings indicate that movements of the eyelid contribute to a greater extent to these EEG potentials than do upward eyeball rotations.


CONCLUSIONS
Care is required in attributing EEG artifacts to movements of either eyeball or eyelid, since our findings suggest that they both contribute to these potentials.
Iwasaki
Masaki
M
Department of Neurology, Cleveland Clinic Foundation, 9500 Euclid Avenue/Desk S90, Cleveland, OH 44195, USA.
Kellinghaus
Christoph
C
Alexopoulos
Andreas V
AV
Burgess
Richard C
RC
Kumar
Arun N
AN
Han
Yanning H
YH
Lüders
Hans O
HO
Leigh
R John
RJ
D000328:Adult; D003215:Conditioning, Eyelid / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005133:Eye Movements / Q000502:physiology*; D005143:Eyelids / Q000502:physiology*; D006801:Humans; D008297:Male