To provide evidence of an organic pathology for essential (idiopathic) blepharospasm, reflex saccadic eye movements in response to randomly stepped visual targets were assessed in seven affected patients and seven age-matched controls using the magnetic scleral search coil technique. The results indicate a significant prolongation in latency and a reduction in gain of horizontal saccades, and an increase in latency and reduction of peak velocity of large downward saccades. These findings suggest an organic component to the aetiology of blepharospasm, the pathology of which also appears to involve the oculomotor system. The pattern of the oculomotor disorder does not allow specific localisation but is consistent with the underlying pathology being localised in the basal ganglia.

Saccadic eye movements in essential blepharospasm.

In order to test the accuracy of lidblink artifact monitoring with EOG during recordings of horizontal saccadic eye movements by means of Infrared Reflection Oculography (IROG), the influences of EOG-recorded blinks of different size on amplitude, peak velocity, and duration of horizontal saccades were studied in ten healthy volunteers. During the study, a simpler blink monitoring technique was developed using IROG itself. in six subjects the conventional ‘retinoelectric’ (EOG) and the new ‘photoelectric’ (IROG) blink artifact monitoring methods were simultaneously employed. A comparison of the two methods showed that photoelectric blink monitoring not only is much simpler to install, but also yields less false positive, as well as less false negative results than retinoelectric monitoring. in addition, photoelectric monitoring gives a continuous control of the placement of the photo cells with respect to the horizontal plane, which is important to avoid asymmetric blink artifacts in the IROG recordings d...

Lidblink artifacts in recordings of horizontal saccadic eye movements with the infrared reflection method: Analysis and presentation of a new monitoring technique

Jacqueline Van Der Hoef

Papers

Lidblink artifacts in recordings of horizontal saccadic eye movements with the infrared reflection method: Analysis and presentation of a new monitoring technique