Broad and Long-Lasting Vision Improvements in Youth With Infantile Nystagmus After Home Training With a Perceptual Learning App.
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ABSTRACT:
SUBMITTER: Huurneman B
PROVIDER: S-EPMC8417383 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:PURPOSE:To evaluate structural grading and quantitative segmentation of foveal hypoplasia using handheld OCT, versus preferential looking (PL), as predictors of future vision in preverbal children with infantile nystagmus. DESIGN:Longitudinal cohort study. PARTICIPANTS:Forty-two patients with infantile nystagmus (19 with albinism, 17 with idiopathic infantile nystagmus, and 6 with achromatopsia) were examined. METHODS:Spectral-domain handheld OCT was performed in preverbal children up to 36 months of age. Foveal tomograms were graded using our 6-point grading system for foveal hypoplasia and were segmented for quantitative analysis: photoreceptor length, outer segment (OS) length, and foveal developmental index (FDI; a ratio of inner layers versus total foveal thickness). Patients were followed up until they could perform chart visual acuity (VA) testing. Data were analyzed using linear mixed regression models. Visual acuity predicted by foveal grading was compared with prediction by PL, the current gold standard for visual assessment in infants and young children. MAIN OUTCOME MEASURES:Grade of foveal hypoplasia, quantitative parameters (photoreceptor length, OS length, FDI), and PL VA were obtained in preverbal children for comparison with future chart VA outcomes. RESULTS:We imaged 81 eyes from 42 patients with infantile nystagmus of mean age 19.8 months (range, 0.9-33.4 months; standard deviation [SD], 9.4 months) at the first handheld OCT scan. Mean follow-up was 44.1 months (range, 18.4-63.2 months; SD, 12.0 months). Structural grading was the strongest predictor of future VA (grading: r = 0.80, F = 67.49, P < 0.0001) compared with quantitative measures (FDI: r = 0.74, F = 28.81, P < 0.001; OS length: r = 0.65; F = 7.94, P < 0.008; photoreceptor length: r = 0.65; F = 7.94, P < 0.008). Preferential looking was inferior to VA prediction by foveal grading (PL: r = 0.42, F = 3.12, P < 0.03). CONCLUSIONS:Handheld OCT can predict future VA in infantile nystagmus. Structural grading is a better predictor of future VA than quantitative segmentation and PL testing. Predicting future vision may avert parental anxiety and may optimize childhood development.
| S-EPMC7105819 | biostudies-literature
Project description:PurposeResearch on infantile nystagmus syndrome (INS) and velocity discrimination is limited, and no research has examined velocity discrimination in subjects with INS at their null position and away from it. This study aims to investigate how individuals with INS perform, compared with controls, when carrying out velocity discrimination tasks. Particularly, the study aims to assess how the null position affects their performance.MethodsINS subjects (N = 21, mean age 24 years; age range, 15-34 years) and controls (N = 16, mean age 26 years; age range, 22-39 years) performed horizontal and vertical velocity discrimination tasks at two gaze positions. Eighteen INS subjects were classified as idiopathic INS and three had associated visual disorders (two had oculocutaneous albinism, and one had congenital cataract). For INS subjects, testing was done at the null position and 15° away from it. If there was no null, testing was done at primary gaze position and 15° away from primary. For controls, testing was done at primary gaze position and 20° away from primary. Horizontal and vertical velocity discrimination thresholds were determined and analyzed.ResultsINS subjects showed significantly higher horizontal and vertical velocity discrimination thresholds compared with controls at both gaze positions (P < 0.001). Horizontal thresholds for INS subjects were elevated more than vertical thresholds (P < 0.0001) for INS subjects but not for controls. Within the INS group, 12 INS subjects who had an identified null position showed significantly lower horizontal and vertical thresholds at the null than at 15° away from it (P < 0.05).ConclusionsVelocity discrimination was impaired in INS subjects, with better performance at the null. These findings could assist in understanding how INS affects the daily activities of patients in tasks involving moving objects, and aid in developing new clinical visual function assessments for INS.
| S-EPMC8411855 | biostudies-literature
Project description:Infantile nystagmus (IN) may result from aetiologies including albinism and FRMD7 mutations. IN has low prevalence, and twins with IN are rare. Whilst discordant presentation has been previously reported for IN, we present for the first time the comprehensive assessment of diagnostically discordant monozygotic twins. From a cohort of over 2000 patients, we identified twins and triplets discordant for nystagmus. Using next-generation sequencing, high-resolution infra-red pupil tracking and optical coherence tomography, we characterised differences in genotype and phenotype. Monozygotic twins (n = 1), dizygotic twins (n = 3) and triplets (n = 1) were included. The monozygotic twins had concordant TYR variants. No causative variants were identified in the triplets. Dizygotic twins had discordant variants in TYR, OCA2 and FRMD7. One unaffected co-twin demonstrated sub-clinical nystagmus. Foveal hypoplasia (FH) was noted in four of five probands. Both co-twins of the monozygotic pair and triplets displayed FH. In three families, at least one parent had FH without nystagmus. FH alone may be insufficient to develop nystagmus. Whilst arrested optokinetic reflex pathway development is implicated in IN, discordant twins raise questions regarding where differences in development have arisen. In unaffected monozygotes therefore, genetic variants may predispose to oculomotor instability, with variable expressivity possibly responsible for the discordance observed.
| S-EPMC7854608 | biostudies-literature
Project description:Variants in the TUBB3 gene, one of the tubulin-encoding genes, are known to cause congenital fibrosis of the extraocular muscles type 3 and/or malformations of cortical development. Herein, we report a case of a 6-month-old infant with c.967A>G:p.(M323V) variant in the TUBB3 gene, who had only infantile nystagmus without other ophthalmological abnormalities. Subsequent brain magnetic resonance imaging (MRI) revealed cortical dysplasia. Neurological examinations did not reveal gross or fine motor delay, which are inconsistent with the clinical characteristics of patients with the M323V syndrome reported so far. A protein modeling showed that the M323V mutation in the TUBB3 gene interferes with αβ heterodimer formation with the TUBA1A gene. This report emphasizes the importance of considering TUBB3 and TUBA1A tubulinopathy in infantile nystagmus. A brain MRI should also be considered for these patients, although in the absence of other neurologic signs or symptoms.
| S-EPMC8071555 | biostudies-literature
Project description:PurposeResearch on infantile nystagmus syndrome (INS) and motion perception is limited. We investigated how individuals with INS perform coherent motion tasks. Particularly, we assessed how the null position affects their performance.MethodsSubjects with INS and controls identified the direction of coherent motion stimuli (22 subjects with INS and 13 controls) in a two-alternative forced-choice design. For subjects with INS, testing was done at the null position and 15 degrees away from it. If there was no null, testing was done at primary gaze position and 15 degrees away from primary. For controls, testing was done at primary gaze position and 20 degrees away from primary. Horizontal and vertical motion coherence thresholds were determined.ResultsSubjects with INS showed significantly higher horizontal and vertical motion coherence thresholds compared with controls at both gaze positions (P < 0.001). Within the INS group, for 12 subjects with INS who had an identified null position, no differences in coherence thresholds were found between their null and 15 degrees away from it (P > 0.05).ConclusionsCoherent motion perception was impaired in subjects with INS. The null position did not significantly influence motion coherence thresholds for either horizontal or vertical motion.
| S-EPMC8802013 | biostudies-literature
Project description:We describe a 3 month-old female floppy infant with hypertrophic cardiomyopathy, serum enzyme levels, which were characterized by an aspartate aminotransferase level of 144 U/l, alanine transaminase 240 U/L and creatine kinase level of 543 U/l. On the basis of the clinical signs and laboratory results, acid α-glucosidase activity was determined from dried blood spots resulting lower than the normal range (0.2 mmol/L/h: normal reference range: 1,86-21,9 mmol/L/h) and leading to a diagnosis of infantile Pompe disease. She also showed multi-directional nystagmus. Refractive errors, ptosis and strabismus are described in infantile Pompe Disease, while nystagmus is rarely reported before. Therefore with this paper we highlight an atypical ocular symptom, whose uncertain pathogenesis, to be taken into consideration, because by now, with increasing survival with ERT, new phenotypes of Pompe disease are taking shape.
| S-EPMC7716971 | biostudies-literature
Project description:Idiopathic infantile nystagmus (IIN) is an inherited disorder in which the nystagmus arises independently of any other symptoms, leading to the speculation that the disorder represents a primary defect in the area of the brain responsible for ocular motor control. The inheritance patterns are heterogeneous, however the most common form is X-linked. FRMD7 resides at Xq26-27 and approximately 50% of X-linked IIN families map to this region. Currently 45 mutations within FRMD7 have been associated with IIN, confirming the importance of FRMD7 in the pathogenesis of the disease. Although mutations in FRMD7 are known to cause IIN, very little is known about the function of the protein. FRMD7 contains a conserved N-terminal FERM domain suggesting that it may provide a link between the plasma membrane and actin cytoskeleton. Limited studies together with the knowledge of the function of other FERM domain containing proteins, suggest that FRMD7 may play a role in membrane extension during neuronal development through remodeling of the actin cytoskeleton.
| S-EPMC3163398 | biostudies-literature
Project description: Not available
| S-EPMC8484540 | biostudies-literature
Project description:PurposeOur primary aim was to compare adult full-field ERG (ffERG) responses in albinism, idiopathic infantile nystagmus (IIN), and controls. A secondary aim was to investigate the effect of within-subject changes in nystagmus eye movements on ffERG responses.MethodsDilated Ganzfeld flash ffERG responses were recorded using DTL electrodes under conditions of dark (standard and dim flash) and light adaptation in 68 participants with albinism, 43 with IIN, and 24 controls. For the primary aim, the effect of group and age on ffERG responses was investigated. For the secondary aim, null region characteristics were determined using eye movements recorded prior to ffERG recordings. ffERG responses were recorded near and away from the null regions of 18 participants also measuring the success rate of recordings.ResultsFor the primary aim, age-adjusted photopic a- and b-wave amplitudes were consistently smaller in IIN compared with controls (P < 0.0001), with responses in both groups decreasing with age. In contrast, photopic a-wave amplitudes increased with age in albinism (P = 0.0035). For the secondary aim, more intense nystagmus significantly reduced the success rate of measurable responses. Within-subject changes in nystagmus intensity generated small, borderline significant differences in photopic b-wave peak times and a-and b-wave amplitudes under scotopic conditions with standard flash.ConclusionsAge-adjusted photopic ffERG responses are significantly reduced in IIN adding to the growing body of evidence of retinal abnormalities in IIN. Differences between photopic responses in albinism and controls depend on age. Success at obtaining ffERG responses could be improved by recording responses at the null region.
| S-EPMC10996992 | biostudies-literature
Project description:Contrast sensitivity is mostly used as a tool for testing aspects of visual functions. Infantile nystagmus is a pathological phenomenon that affects the spatial-temporal visual functions due to spontaneous oscillating movements of the eyes. We examined the spatial-temporal aspects of nystagmus perception, aiming to investigate the mechanisms underlying the deterioration of their visual performance. We tested the monocular and binocular contrast sensitivity of nystagmus and normally sighted subjects by measuring contrast detection of a Gabor target with spatial frequencies slightly above the cutoff threshold of each subject (nystagmus ~3; controls = 9cpd; presentation times 60-480 ms). The dominant eye of nystagmus revealed large differences over the non-dominant eye, highlighting the superiority of the dominant over the non-dominant eye in nystagmus. In addition, binocular summation mechanism was impaired in majority of the nystagmus subjects. Furthermore, these differences are not attributed to differences in visual acuity. Moreover, the visual performance in nystagmus continue to improve for longer presentation time compared with controls and was longer in the poor eye. Since the results are not due to differences in eye movements and strabismus, we suggest that the differences are due to developmental impairment in the visual system during the critical period.
| S-EPMC7080729 | biostudies-literature