The Neurotological Significance of Alterations of Pursuit Eye Movements and the Pendular Eye Tracking Test

Abstract

Smooth pursuit eye movements can be studied if the patient follows a target that moves horizontally in a pendular way. The eye movements can be recorded with electrooculographic technique, and the tracings obtained studied for abnormalities. This constitutes the Pendular Eye Trackin Test (PETT). Three different deformations of PETT tracings have been observed: 1) a %asically normal shaped curve with superimposed fast movements; 2 ) a deformed curve and 3) an absence of the normal sinusoidal tracing. In diseases of the inner ear, the PETT usually shows a normal curve, but sometimes can be slightly modified by the appearance of small, fast movements. In diseases of the central nervous system, the PETT is very often altered, and these alterations are very distinct. Although the three main deformations of the curve can be observed in lesions of any localization in the nervous system, there appears to be certain systematization. The normal curve with superimposed fast movements tends to be associated with cerebellar disease. The deformed curve often appears in connection with a more widespread localization of encephalic lesions, perhaps due to repercussion in the brain stem; and the disappearance of the curve apparently is due to an important lesion in the oculomotor athways in the tegmentum of the pons and midbrain. The PETT has localizing diagnosic vayue, especially in the differentiation between diseases of the internal ear and of the central ( neurological) connections of the vestibular system.

Horizontal Gaze Nystagmus: A Review of Vision Science and Application Issues

“…The average saccade was 2.5° (SD = 0.5), presumably large enough to be observed by the naked eye. However, in contrast to the previous findings, several authors have reported tracking at 30°/sec or more with few or no sizable saccades (11,73,74). …”

Assessment of Head Shaking Test in Neuro-Otological Practice

“…[3]; (6) a search for positioning nystagmus as de scribed by Dix and Hallpike [4]; (7) a search for cervical nystagmus as described by Greiner et al [7]; (8) a search for vertebro-basilar deprivation nys tagmus as described by Caussc ct al. [2]; (9) a bithermal caloric test according to Freyss et al [5j; directional preponderance and canal paresis were manually calculated, resulting in a computation of the total number of beats during the culmination; results were compared with the normal range for each laboratory;…”

Quantitative Measurement of Smooth Pursuit Using the Continuously Changing Sinusoidal Wave in Neurological Patients

“…Also Corvera [6], Norrden [5] and Lhneda [12] used the sinusoidal wave in their examina tions. On the other hand Baloh et al [7], Schalen [9], Schalen et al [10], Yamazaki [13] and Tamada et al [14] utilized triangu lar target waves.…”

“…The slow eye movement is one of the principal subsystems in the oculomo tor system together with the fast eye move ment (e.g. saccadic eye movement) [2][3][4], Clinical reports of smooth pursuit of patients with neurological disorders were reported by Jung and Kornhuber [4], Norrden [5] and Corvera [6], However, their analyses were based on qualitative evaluation using the ENG recording paper. Quantitative analysis of smooth pursuit has been tried by Baloh et al [7], Mizukoshi et al [8], Schalen [9] and Schalen et al [10], In most of these reports, the triangular wave or velocity ramp were utilized as target movements.…”