Neuropsychologia, May 2012, Vol.50(6), pp.1164-1177
► Neglect patients often show an ipsilesional shift of their subjective auditory midline. ► Leftsided optokinetic stimulation (OKS) transiently normalized this auditory midline shift in leftsided neglect, and led to a significant positive after-effect 30 min post-stimulation. ► Repetitive leftward OKS (20 treatment sessions) led to a significant and enduring reduction of both visual auditory neglect phenomena while visual scanning therapy had no effect on auditory and only small effects on visual neglect. ► In conclusion, OKS induces significant recovery from auditory and visual neglect. Optokinetic stimulation (OKS) modulates many facets of the neglect syndrome. This sensory stimulation technique is known to activate multiple brain regions (temporo-parietal cortex, basal ganglia, brain stem, cerebellum) some of which are involved in auditory and visual space coding. Here, we evaluated whether OKS modulates auditory neglect and induces a sustained effect (Study 1), and whether repetitive OKS recovers auditory neglect (Study 2). In Study 1, 20 patients with visuospatial neglect and auditory neglect in an auditory midline task following rightsided stroke were randomly allocated to an experimental and a control group matched for neglect severity and socio-demographic factors. Both groups showed a stable, pathological shift of their auditory subjective median plane (ASMP) in front space to the right side. During leftward OKS the experimental group showed a complete normalization of the shift of the ASMP, which endured until 30 min poststimulation, and returned almost to baseline values 24 h after OKS. In contrast, the control group who viewed the identical but static dot pattern, showed neither change in their ASMP during this condition, nor any significant change at 30 min or 24 h poststimulation. In Study 2, we show in two samples of neglect patients ( = 3 each) that repetitive leftward OKS with smooth pursuit eye movements as a therapy induces lasting improvements in auditory (the ASMP) and visual neglect while visual scanning therapy yielded no measurable effects on auditory significantly smaller effects on visual neglect. In conclusion, the experiments show that a single session of OKS induces rapid though transient recovery from auditory neglect including a sustained effect after termination of stimulation, while OKS therapy yields enduring and multimodal recovery from auditory and visual neglect. OKS therapy with pursuit eye movements therefore represents a multimodally effective and easily applicable technique for the treatment of auditory and visual neglect.
Auditory ; Visual ; Neglect ; Space ; Crossmodal ; Brain ; Treatment ; Medicine
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