Relationship between Visual Perception and Microstructural Change of the Superior Longitudinal Fasciculus in Patients with Brain Injury in the Right Hemisphere: A Preliminary Diffusion Tensor Tractography Study

Abstract

Right hemisphere brain damage often results in visual-spatial deficits. Because various microstructural changes of the superior longitudinal fasciculus (SLF) after a stroke in the right hemisphere affect visual perception, including neglect, the present study investigates the relationship between both microstructural change and lateralization of SLF and visual perception, using diffusion tensor imaging (DTI) in patients with lesions in the right hemisphere. Eight patients with strokes (five patients with intracranial hemorrhage, and three patients with infarction; mean age of 52.5 years) and 16 mean-age-matched healthy control subjects were involved in this study. The visual perception of all eight patients was assessed with the motor-free visual perception test (MVPT), and their SLFs were reconstructed using DTI. The results showed that there was a significant difference between the DTI parameters of the patients and the control subjects. Moreover, patients with microstructural damage to the right SLF showed impairment of visual perception. In patients with damage to both the dorsal and ventral pathways of the right SLF, spatial neglect was present. However, although a leftward SLF asymmetry was revealed in our patients, this lateralization did not show a relationship with visual perception. In conclusion, the microstructural changes of the right SLF play an important role in visual perception, and both pathways contribute to spatial neglect, but leftward lateralization of the right SFL activity after a stroke does not contribute to general visual perception.

Implementing New Technologies to Improve Visual–Spatial Functions in Patients with Impaired Consciousness

“…They observed a dramatically decreased activity, impaired responses to visual stimuli and spatial perception deficits of the primary visual cortical neurons [ 34 ]. Impaired visual perception is observed in approximately 75% of the patients with brain damage, and it frequently results in serious limitations concerning independent functioning [ 14 ]. These patients demonstrate visual field.…”

“…Observation of the patients allowed to discover that the subjects with initial problems with extreme saccadic movements (quick looking at the other side of the screen) were able to look in the direction they previously found difficult to see after completion of the oculomotor training course. In certain patients, difficulties with symmetric ocular movements result from, e.g., visual–spatial deficits (or neglect) [ 14 ]. The neglect is generally defined as inability to perceive, to report and to orient to sensory events towards one side of a space, contralaterally to the side of the lesion, with or without a primary sensory deficit [ 36 , 37 ].…”

“…A particularly great amount of time in the therapy of patients with brain damage is dedicated to the training and elimination of cognitive deficits [ 14 ]. Proper cognitive functioning is essential for these patients, as it is the basis for proper performance of specific daily activities where continuous choices of adequate strategies are necessary to achieve the goal [ 15 ].…”

Widespread White Matter Alterations in Patients With Visual Snow Syndrome

“…The SLF is involved in speech processing ( 31 , 32 ), musical processing ( 33 ), spatial attention ( 34 ) and memory ( 35 ), decision making ( 36 ), visual perception ( 37 ), and perceptual organisation ( 38 ). For example, right-hemisphere brain damage e.g., induced by stroke often results in visual-spatial deficits, such as a neglect ( 37 ).…”

“…The SLF is involved in speech processing ( 31 , 32 ), musical processing ( 33 ), spatial attention ( 34 ) and memory ( 35 ), decision making ( 36 ), visual perception ( 37 ), and perceptual organisation ( 38 ). For example, right-hemisphere brain damage e.g., induced by stroke often results in visual-spatial deficits, such as a neglect ( 37 ). McKendrick et al ( 7 ) demonstrated that patients with visual snow demonstrated reduced centre-surround contrast suppression and elevated luminance increment thresholds in noise but did not differ on a global form or global motion task.…”