Unilateral occipital lesion causing hemianopia affects the acoustic saccadic programming

Traccis, S.; Puliga, M. V.; Ruiu, M. C.; Marras, M. A.; Rosati, G

doi:10.1212/wnl.41.10.1633

Cited by 9 publications

(3 citation statements)

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“…Nevertheless, our group of neuro-ophthalmic patients had higher temporal lags and spatio-temporal latencies than controls (see Figures 2A,B). Numerous studies have shown that patients with neuro-ophthalmic VFD have prolonged latencies compared to controls in response to moving or stationary targets -often in the range of 20-100 ms more than controls (Sharpe et al, 1979;Meienberg et al, 1981;Traccis et al, 1991;Rizzo and Robin, 1996;Barton and Sharpe, 1998;Fayel et al, 2014). Our group has previously shown through simulations (Grillini et al, 2018;Gestefeld et al, 2020) and in actual patients (Soans et al, 2021) that this is indeed the case.…”

Section: Assigned Clustermentioning

confidence: 55%

Patients Prefer a Virtual Reality Approach Over a Similarly Performing Screen-Based Approach for Continuous Oculomotor-Based Screening of Glaucomatous and Neuro-Ophthalmological Visual Field Defects

et al. 2021

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Standard automated perimetry (SAP) is the gold standard for evaluating the presence of visual field defects (VFDs). Nevertheless, it has requirements such as prolonged attention, stable fixation, and a need for a motor response that limit application in various patient groups. Therefore, a novel approach using eye movements (EMs) – as a complementary technique to SAP – was developed and tested in clinical settings by our group. However, the original method uses a screen-based eye-tracker which still requires participants to keep their chin and head stable. Virtual reality (VR) has shown much promise in ophthalmic diagnostics – especially in terms of freedom of head movement and precise control over experimental settings, besides being portable. In this study, we set out to see if patients can be screened for VFDs based on their EM in a VR-based framework and if they are comparable to the screen-based eyetracker. Moreover, we wanted to know if this framework can provide an effective and enjoyable user experience (UX) compared to our previous approach and the conventional SAP. Therefore, we first modified our method and implemented it on a VR head-mounted device with built-in eye tracking. Subsequently, 15 controls naïve to SAP, 15 patients with a neuro-ophthalmological disorder, and 15 glaucoma patients performed three tasks in a counterbalanced manner: (1) a visual tracking task on the VR headset while their EM was recorded, (2) the preceding tracking task but on a conventional screen-based eye tracker, and (3) SAP. We then quantified the spatio-temporal properties (STP) of the EM of each group using a cross-correlogram analysis. Finally, we evaluated the human–computer interaction (HCI) aspects of the participants in the three methods using a user-experience questionnaire. We find that: (1) the VR framework can distinguish the participants according to their oculomotor characteristics; (2) the STP of the VR framework are similar to those from the screen-based eye tracker; and (3) participants from all the groups found the VR-screening test to be the most attractive. Thus, we conclude that the EM-based approach implemented in VR can be a user-friendly and portable companion to complement existing perimetric techniques in ophthalmic clinics.

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Section: Assigned Clustermentioning

confidence: 55%

Patients Prefer a Virtual Reality Approach Over a Similarly Performing Screen-Based Approach for Continuous Oculomotor-Based Screening of Glaucomatous and Neuro-Ophthalmological Visual Field Defects

et al. 2021

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“…Saccade endpoint accuracy is not considered due to the large stimulus eccentricities. Hemispherectomized patients are also known generally to use different movement strategies to acquire targets in the seeing and blind hemifields (Herter & Guitton, 2007;Traccis, Pulgia, Ruiu, Marras, & Rosati, 1991). Saccade metrics are not considered because the EOG signal is inherently too noisy to permit accurate velocity profiles.…”

Section: Discussionmentioning

confidence: 99%

Control of Reflexive Saccades following Hemispherectomy

Reuter‐Lorenz

Herter

Guitton

2011

Journal of Cognitive Neuroscience

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Abstract■ Individuals who have undergone hemispherectomy for treatment of intractable epilepsy offer a rare and valuable opportunity to examine the ability of a single cortical hemisphere to control oculomotor performance. We used peripheral auditory events to trigger saccades, thereby circumventing dense postsurgical hemianopia. In an antisaccade task, patients generated numerous unintended short-latency saccades toward contralesional auditory events, indicating pronounced limitations in the ability of a single hemicortex to exert normal inhibitory control over ipsilateral (i.e., contralesional) reflexive saccade generation. Despite reflexive errors, patients retained an ability to generate correct antisaccades in both directions. The prosaccade task revealed numerous contralesional express saccades, a robust contralesional gap effect, but the absence of both effects for ipsilesional saccades. These results indicate limits to the saccadic control capabilities following hemispherectomy: A single hemicortex can mediate antisaccades in both directions, but plasticity does not extend fully to the bilateral inhibition of reflexive saccades. We posit that these effects are due to altered control dynamics that reduce the responsivity of the superior colliculus on the intact side and facilitate the release of an auditory-evoked ocular grasp reflex into the blind hemifield that the intact hemicortex has difficulty suppressing. ■

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“…Conversely, current knowledge about the impairment of saccadic eye movements in patients with cortical damage including early visual cortices is sparse and rare (Barton, 2001;Leigh and Kennard, 2004). One of the exceptions is a study that examined saccades to auditory targets in patients suffering from hemianopia attributable to occipital lesions (Traccis et al, 1991). This result implies that occipital lesions influence a common mechanism of saccade control used for visual and auditory targets.…”

Section: Discussionmentioning

confidence: 99%

Striate Cortical Lesions Affect Deliberate Decision and Control of Saccade: Implication for Blindsight

Yoshida

Takaura²,

Katō³

et al. 2008

J. Neurosci.

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Monkeys with unilateral lesions of the primary visual cortex (V1) can make saccades to visual stimuli in their contralateral ("affected") hemifield, but their sensitivity to luminance contrast is reduced. We examined whether the effects of V1 lesions were restricted to vision or included later stages of visual-oculomotor processing. Monkeys with unilateral V1 lesions were tested with a visually guided saccade task with stimuli in various spatial positions and of various luminance contrasts. Saccades to the stimuli in the affected hemifield were compared with those to the near-threshold stimuli in the normal hemifield so that the performances of localization were similar. Scatter in the end points of saccades to the affected hemifield was much larger than that of saccades to the near-threshold stimuli in the normal hemifield. Additional analysis revealed that this was because the initial directional error was not as sufficiently compensated as it was in the normal hemifield. The distribution of saccadic reaction times in the affected hemifield tended to be narrow. We modeled the distribution of saccadic reaction times by a modified diffusion model and obtained evidence that the decision threshold for initiation of saccades to the affected hemifield was lower than that for saccades to the normal hemifield. These results suggest that the geniculostriate pathway is crucial for on-line compensatory mechanisms of saccadic control and for decision processes. We propose that these results reflect deficits in deliberate control of visual-oculomotor processing after V1 lesions, which may parallel loss of visual awareness in human blindsight patients.

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Unilateral occipital lesion causing hemianopia affects the acoustic saccadic programming

Cited by 9 publications

References 0 publications

Patients Prefer a Virtual Reality Approach Over a Similarly Performing Screen-Based Approach for Continuous Oculomotor-Based Screening of Glaucomatous and Neuro-Ophthalmological Visual Field Defects

Patients Prefer a Virtual Reality Approach Over a Similarly Performing Screen-Based Approach for Continuous Oculomotor-Based Screening of Glaucomatous and Neuro-Ophthalmological Visual Field Defects

Control of Reflexive Saccades following Hemispherectomy

Striate Cortical Lesions Affect Deliberate Decision and Control of Saccade: Implication for Blindsight

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