Hierarchical processing of visual stimuli in nephropathic cystinosis

Abstract

Previous studies have shown that individuals with cystinosis may exhibit difficulty with visuospatial tasks. Global and local (hierarchical) processing are specific types of visuospatial tasks mediated by the right and left parietal lobes respectively. The study objective was to determine whether individuals with cystinosis and carriers of the cystinosin gene mutation show deficits in global and/or local processing.The study included 48 children (32 controls, 16 cystinosis) and 56 adults (25 controls, 25 carriers, and 6 cystinosis). Participants were instructed to replicate 10 hierarchical stimuli to assess global-local processing. The primary outcome measure was mean global and local performance on the hierarchical stimuli task between subgroups. Error subtypes were included to further assess each image. Compared to the control subgroups, adult and child cystinosis patients as well adult carriers demonstrated significant deficits in the global processing of a hierarchical stimulus against a background of unimpaired local processing. Child cystinosis patients performed significantly more poorly than controls on all error subtypes except local shape distortion. Adult cystinosis patients and carriers made significantly more global shape distortion errors than the controls. Our study shows that the cognitive profile documented in cystinosis patients and carriers includes significant difficulties with the global processing of an image. Results of the carrier population are important since they suggest that the cognitive impairments observed in patients cannot be attributed to symptomatic manifestations of the disease. Instead, the global processing deficits observed provide insight into the potential role of the cystinosin gene mutation on neurodevelopmental differences seen in these individuals. K E Y W O R D Scystinosis, lysosomal storage disease, hierarchical processing, visual spatial

Electrophysiological evidence for impaired auditory sensory memory in Cystinosis despite typical sensory processing: An MMN investigation

“…While identification of differences in sensory memory provide a potential biomarker of the effects of cysteamine on brain function to serve as secondary outcome measure for clinical trials, it will be critical to determine whether the deficit varies with other clinically significant symptoms. Furthermore, it will be interesting to determine if similar deficits are seen in unaffected carriers of the mutation, as shown for visual-spatial difficulties (Sathappan & Trauner, 2019), or if they are specific to the effects of cysteamine accumulation. As alluded to above, future work will need to be done to understand the implications of the auditory sensory memory deficit described here.…”

“…Motor deficits and fine motor incoordination have also been described (Trauner, Spilkin, Williams, & Babchuck, 2007;Trauner et al, 2010;Ulmer et al, 2009). Some of these difficulties seem to be likewise present in unaffected heterozygous carriers of the cystinosin gene mutation (Sathappan & Trauner, 2019).…”

“…This pattern appears to emerge early in development and to persist throughout the lifespan (Scarvie, Ballantyne, & Trauner, 1996;Trauner, Chase, Scheller, Katz, & Schneider, 1988), regardless of age at treatment onset (Viltz & Trauner, 2013). Significant difficulties are observed in visual-motor, visual-spatial and visual memory skills, as well as executive function related abilities (Aly et al, 2014;Ballantyne, Spilkin, & Trauner, 2013;Besouw et al, 2010;Sathappan & Trauner, 2019;Viltz & Trauner, 2013), which may particularly hinder academic skills (Ballantyne, Scarvie, & Trauner, 1997). Motor deficits and fine motor incoordination have also been described (Trauner, Spilkin, Williams, & Babchuck, 2007;Trauner et al, 2010;Ulmer et al, 2009).…”

Central Nervous System Complications in Cystinosis: The Role of Neuroimaging

“…Indeed, specific impairments in the processing of visual information, as well as relative weakness in visual motor, visual spatial, and visual memory skills have been described, which may be associated with learning difficulties, primarily in arithmetic. Significant difficulties are observed in executive-function-related abilities [ 12 , 31 , 32 , 33 , 34 , 35 ]. A fine-motor coordination deficit in children and adolescents with cystinosis has also been documented [ 11 ].…”

Event-related potential (ERP) evidence of early visual processing differences in cystinosis

“…This pattern appears to emerge early in development and to persist throughout the lifespan (20,21), regardless of age at treatment onset (22). Significant difficulties have also been described in visual-motor, visual-spatial and visual memory skills (22)(23)(24)(25)(26), but see (27) for a report of maintained visual learning in adults with cystinosis. Despite this pattern of relative weaknesses in visual processing domains, very little is known about how the brains of people living with cystinosis process visual information.…”