Pathological Ocular Fixation Instability

Vedel-Jensen, Niels

doi:10.1111/j.1755-3768.1966.tb08062.x

Cited by 10 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A number of studies have proposed that an enlargement of horizontal fixational saccades (microsaccades) produces square-wave coupling in healthy subjects (Ditchburn and Ginsborg, 1953; Vedel-Jensen, 1966; Yamazaki, 1968; Feldon and Langston, 1977; Gowen et al, 2007). To confirm this possibility we calculated the likelihood of a saccade being part of a SWJ as a function of its magnitude.…”

Section: Resultsmentioning

confidence: 99%

“…For instance, microsaccades tend to be smaller than SWJs and often display an oblique trajectory, whereas SWJs appear to be purely horizontal on clinical inspection (SWJ studies have largely focused on neurological patients, whereas microsaccade research is mostly constrained to healthy subjects). Despite these apparent distinctions, minimally enlarged microsaccades (beyond 15–30 arcmin) tend to produce square-wave coupling in healthy subjects (Ditchburn and Ginsborg, 1953; Vedel-Jensen, 1966; Yamazaki, 1968; Feldon and Langston, 1977). SWJs and microsaccades have other important similarities.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Distinctive Features of Saccadic Intrusions and Microsaccades in Progressive Supranuclear Palsy

Otero‐Millan¹,

Serra²,

Leigh³

et al. 2011

J. Neurosci.

109

115

View full text Add to dashboard Cite

The eyes do not stay perfectly still during attempted fixation; fixational eye movements and saccadic intrusions (SIs) continuously change the position of gaze. The most common type of SI, square-wave jerk (SWJ), consists of saccade pairs that appear purely horizontal on clinical inspection: the first saccade moves the eye away from the fixation target and, after a short interval, the second saccade brings it back towards the target. SWJs are prevalent in certain neurological disorders, including progressive supranuclear palsy (PSP). Here we developed an objective method to identify SWJs. We found that SWJs are more frequent, larger and more markedly horizontal in PSP patients than in healthy human subjects. Further, the loss of a vertical component in fixational saccades and SWJs was the eye movement feature that best distinguished PSP patients from controls. We moreover determined that in PSP patients and controls, the larger the saccade the more likely it was part of a SWJ. Further, saccades produced by PSP patients had equivalent properties whether they were part of a SWJ or not, suggesting that normal fixational saccades (microsaccades) are rare in PSP. We propose that fixational saccades and SIs are generated by the same neural circuit, and that, both in PSP patients and in controls, SWJs result from a coupling mechanism that generates a second corrective saccade shortly after a large fixation saccade. Due to brainstem and/or cerebellum impairment, fixational saccades in PSP are abnormally large, and thus more likely to trigger a corrective saccade, giving rise to SWJs.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Distinctive Features of Saccadic Intrusions and Microsaccades in Progressive Supranuclear Palsy

Otero‐Millan¹,

Serra²,

Leigh³

et al. 2011

J. Neurosci.

109

115

View full text Add to dashboard Cite

show abstract

The ocular motor defects in progressive supranuclear palsy

Troost

Daroff

1977

Annals of Neurology

168

View full text Add to dashboard Cite

The results of quantitative infrared horizontal eye movement recordings in 8 patients with progressive supranuclear palsy are presented. Some of the patients had total paralysis of vertical movements, but none had completely lost the ability to perform horizontal eye movements. All patients had a defect in ocular fixation previously undescribed in this condition: the universal presence of square-wave jerks. Analysis of refixation saccades demonstrated hypometria, slow velocity/amplitude relationships, and profound prolongation of duration. The pursuit abnormality, characterized clinically by "cogwheel" eye movements, represented the inability to match eye velocity to target velocity. The ratio of peak eye velocity to peak target velocity (pursuit gain) was 0.2 to 0.5. Defects in the vestibuloocular reflex included inability to increase the gain of the reflex (ratio of peak eye velocity to head velocity) during viewing of a visible, stationary target and failure to suppress the reflex when viewing a target rotating with the head.

show abstract

Saccadic intrusions in Alzheimer-type dementia

et al. 1983

View full text Add to dashboard Cite

Horizontal eye-movement responses of four patients with Alzheimer-type dementia were recorded using the infrared oculographic technique. Abnormally frequent saccadic intrusions occurred during the fixation and slow, smooth pursuit tasks in all four patients. Saccadic intrusions have previously been reported in the literature to occur in normals, in strabismus, in patients with certain neurological disorders, and in schizophrenic patients. This is the first report of a group of Alzheimer-type dements with an eye movement abnormality which cannot be regarded as an ocularmotor reflection of diffuse cerebral dysfunction.

show abstract

Pathological Ocular Fixation Instability

Cited by 10 publications

References 10 publications

Distinctive Features of Saccadic Intrusions and Microsaccades in Progressive Supranuclear Palsy

Distinctive Features of Saccadic Intrusions and Microsaccades in Progressive Supranuclear Palsy

The ocular motor defects in progressive supranuclear palsy

Saccadic intrusions in Alzheimer-type dementia

Contact Info

Product

Resources

About