Refixation saccades with normal gain value occur more frequently with increasing age. The phenomenon has also been observed in different vestibular disorders. In this case, we present a young male with normal gain value and refixation saccades tested with the video head impulse test (vHIT) the day after his cochlear implantation. One month after surgery, refixation saccades were no longer present. This suggests that refixation saccades can occur as a result of temporary pathology such as surgery. Refixation saccades with normal gain values might reflect a partial deficit in the vestibulo-ocular reflex. However, this partial deficit is in conflict with the current way of interpreting vHIT results in which the vestibular function is classified as either normal or pathological based only on the gain value. Refixation saccades, which are evident signs of vestibulopathy, are not considered in the evaluation. A new way of interpreting the vHIT based on the saccades must be considered.
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http://dx.doi.org/10.3389/fneur.2017.00081 | DOI Listing |
Eur J Neurol
December 2024
Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Central Clinical School, University of Sydney, Sydney, New South Wales, Australia.
Background And Purpose: This study was undertaken to examine vestibulo-ocular reflex (VOR) characteristics in myotonic dystrophy type 1 (DM1) and type 2 (DM2) using video head impulse testing (vHIT).
Methods: VOR gain, refixation saccade prevalence, first saccade amplitude, onset latency, peak velocity, and duration were compared in DM1, DM2, age-matched normal controls, and patients with peripheral and central vestibulopathies.
Results: Fifty percent of DM1 and 37.
PLoS One
May 2024
Human in Complex Systems Division, DEVCOM Army Research Laboratory, Aberdeen Proving Ground, Maryland, United States of America.
U.S. service members maintain constant situational awareness (SA) due to training and experience operating in dynamic and complex environments.
View Article and Find Full Text PDFSci Rep
February 2024
Department of Otorhinolaryngology, Coimbra University Hospital Centre, Praceta Mota Pinto, 3000-135, Coimbra, Portugal.
Usher Syndrome classification takes into account the absence of vestibular function but its correlation with genotype is not well characterized. We intend to investigate whether video Head Impulse Test (vHIT) is useful in screening and to differentiate Usher Syndrome types. 29 Usher patients (USH) with a genetically confirmed diagnosis and 30 healthy controls were studied with vHIT and dizziness handicap inventory questionnaire (DHI).
View Article and Find Full Text PDFJ Exp Psychol Learn Mem Cogn
August 2024
Department of Linguistics and Languages, McMaster University.
Research on first language (L1) reading has long since established the link between the proficiency of the reader and their efficiency in oculomotor control. More proficient readers make longer saccades and land closer to the word's center, which is a word's optimal viewing position, and make fewer refixations. Eye-tracking studies of second language (L2) reading have so far provided little evidence in this regard.
View Article and Find Full Text PDFAtten Percept Psychophys
January 2024
Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany.
Under natural viewing conditions, complex stimuli such as human faces are typically looked at several times in succession, implying that their recognition may unfold across multiple eye fixations. Although electrophysiological (EEG) experiments on face recognition typically prohibit eye movements, participants still execute frequent (micro)saccades on the face, each of which generates its own visuocortical response. This finding raises the question of whether the fixation-related potentials (FRPs) evoked by these tiny gaze shifts also contain psychologically valuable information about face processing.
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