alexa Visual Impairment Affects the Perception of Reality: Visual Processing Deficits

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Visual Impairment Affects the Perception of Reality: Visual Processing Deficits

Cognitive deficits are one of the core features of schizophrenia, and affects on the patients' daily functioning. Research has provided evidence for a wide variety of cognitive dysfunctions in areas such as attention, memory, language, executive functions and visual perception [1-4]. However, although individuals with schizophrenia are known to suffer from various cognitive difficulties, one of the important diagnostic characteristic of these patients is reality testing impairment, which can be related to poor perceptual processing (e.g. Stern, Caligor, Clarkin,... & Kernberg). Within the domain of visual perception, studies have shown that adults with schizophrenia perform poorly on visual tasks, especially on tasks requiring high-level processing [5,6]. This high level of processing involves two main mechanisms: the spatial information processing (dorsal stream) and the object information processing (ventral stream) [7]. Even though there is consistency with higher visual processing disability, studies show that adult patient with schizophrenia display more deficits in object and form perception than in spatial perception [8,9].

The visual system allows objects to be recognized even when there is missing visual information. For example when the object is obstructed or only partially in the field of view, or when there are fragmented changes in their spatial properties. The ability to recognize common objects when they are shown from an unusual viewpoint involves executive and top-down processes [10] and may require the use of mental manipulations, such as 'mental rotation'. Mental rotation is the spatial ability which enables the individual to both transform visual images and to use images of common objects stored in the short-term memory [11]. Some theorists of visual object recognition believe that mental rotation is integral to the recognition process [12] while others assert that object recognition is not based on a continuous alteration process, such as mental rotation. For example, [13] have suggested that in order to recognize an object, people compare it with mentally stored representations, which may or may not exist. If the object is recognized, it means that information is drawn from semantic memory, including the production of its name [14] have proposed a model in which the recognition process relies on the accumulation of evidence in populations of viewpoint-specific neurons.

The majority of cognitive deficits found in adult patients with schizophrenia have also been demonstrated in children and adolescents with schizophrenia [15,16]. This may have numerous implications for the ability of schizophrenics to acquire new skills. From a neurodevelopmental point of view, cognitive functions and processes undergo substantial development throughout childhood and adolescence [17,18]. For instance, Casey, Giedd and Thomas found that memory and attention continue to develop throughout childhood and adolescence. Mental rotation ability was found to be acquired at approximately age seven and to continue developing far beyond that age [19,20,21]. Kail, Pellegrino and Carter suggested that the basic processes of information manipulation become automatized with age and that this shows itself in quicker reaction times. The question that arises with respect to patients with schizophrenia is whether they can achieve normal cognitive maturation or whether their cognitive impairment worsens over the course of adolescence.

There is a relative paucity of studies assessing adolescents with schizophrenia. In the present study we tested object naming and mental rotation performance in adolescents with schizophrenia and contrasted it with the performance of two healthy control groups, adolescents and young adults. The addition of the healthy young adults group (aged 21-30) was to allow a reference for ripe normal functions and perceptual abilities. We hypothesized that the visual processes that develop during adolescence will be damaged in schizophrenic adolescent patients, while these same processes will continue to develop normally in healthy adolescents. These results shed light on the possibility that damage to normal development of the visual system, is connected with the outbreak of the disease and in reality testing symptom.

Citation: Ariela Gigi, Daniela Karni, Oren Eilam (2015) Visual Impairment Affects the Perception of Reality: Visual Processing Deficits among Adolescents with Schizophrenia. J Psychiatry 18:232. doi: 10.4172/Psychiatry.1000232 

 
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