Cortical activation in hemianopia after stroke

Nelles, Gereon; Greiff, Armin de; Pscherer, Anja; Forsting, Michael; Gerhard, H.; Esser, Joachim; Hc, Diener

doi:10.1016/j.neulet.2007.08.028

Cited by 34 publications

(18 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alterations in down-stream, higher cortical areas, not directly affected by the lesion, were already demonstrated by gene expression studies [42] and single-unit recordings in animal models [43,44], as well as MEG [45] and fMRI studies in humans [20,[46][47][48][49][50][51][52]. This is in line with findings from motor [53,54] and attentional systems [55] where lesion-induced network modifications have been increasingly recognized and appreciated.…”

Section: Global Effect Of Visual System Lesionssupporting

confidence: 76%

The second face of blindness: Processing speed deficits in the intact visual field after pre- and post-chiasmatic lesions

Bola

Gall

Sabel

2013

Journal of the Neurological Sciences

View full text Add to dashboard Cite

Purpose: Damage along the visual pathway results in a visual field defect (scotoma), which retinotopically corresponds to the damaged neural tissue. Other parts of the visual field, processed by the uninjured tissue, are considered to be intact. However, perceptual deficits have been observed in the ''intact'' visual field, but these functional impairments are poorly understood. We now studied temporal processing deficits in the intact visual field of patients with either pre-or postchiasmatic lesions to better understand the functional consequences of partial blindness.Methods: Patients with pre-(n = 53) or post-chiasmatic lesions (n = 98) were tested with high resolution perimetry -a method used to map visual fields with supra-threshold light stimuli. Reaction time of detections in the intact visual field was then analyzed as an indicator of processing speed and correlated with features of the visual field defect.

show abstract

Section: Global Effect Of Visual System Lesionssupporting

confidence: 76%

The second face of blindness: Processing speed deficits in the intact visual field after pre- and post-chiasmatic lesions

Bola

Gall

Sabel

2013

Journal of the Neurological Sciences

View full text Add to dashboard Cite

show abstract

“…It has been already shown that synchronization evoked by a stimulus presented in the seeing field of hemianopia patients is compromised (Schadow et al, 2009) and that different neural networks are activated during visual tasks in hemianopia subjects than in healthy controls (Perez et al, 2012). We hypothesize that lesion-induced disturbance of interhemispheric interactions might be the key mechanism, as in the lesioned hemisphere visually induced activation is weaker (Goebel et al, 2001; Nelles et al, 2007) and delayed (Rossion et al, 2000; Schoenfeld et al, 2002) when compared to the uninjured hemisphere. Reduced and delayed activation in the lesioned hemispheres might hamper the interhemispheric functional connectivity and consequently synchronization in the uninjured hemisphere (Schadow et al, 2009).…”

Section: Discussionmentioning

confidence: 98%

“…It has been shown that the visual cortex lesion affects activity and connectivity of down-stream visual structures (Goebel et al, 2001; Schoenfeld et al, 2002; Nelles et al, 2007). Crucially, unilateral cortical lesions alter activity of visual cortical areas not only in the damaged, but also in the seemingly unaffected (uninjured) hemisphere, which has been shown in animal model (Rushmore and Payne, 2003) and in patients (Henriksson et al, 2007; Nelles et al, 2007). Changes in activity are related to modification of anatomical (Bridge et al, 2008) and functional connectivity (Silvanto et al, 2009) between both hemispheres.…”

Section: Discussionmentioning

confidence: 99%

“Sightblind”: Perceptual Deficits in the “Intact” Visual Field

2013

View full text Add to dashboard Cite

Unilateral visual cortex lesions caused by stroke or trauma lead to blindness in contralateral visual field – a condition called homonymous hemianopia. Although the visual field area processed by the uninjured hemisphere is thought to be “intact,” it also exhibits marked perceptual deficits in contrast sensitivity, processing speed, and contour integration. Such patients are “sightblind” – their blindness reaches far beyond the primary scotoma. Studies showing perceptual deficits in patients’ intact fields are reviewed and implications of these findings are discussed. It is concluded that consequences of partial blindness are greater than previously thought, since perceptual deficits in the “intact” field likely contribute to subjective vision loss in patients with visual field defect. This has important implications for vision diagnosis and rehabilitation.

show abstract

“…Our results indicated before and after training that ME using the affected and unaffected hand activated the contralateral SMC area. In patients with stroke, the activation intensity of the contralateral SMC was positively correlated with improvement in motor function [16, 32, 38]. Our results demonstrated that ME using the affected hand increased the number of voxels activated in the contralateral SMC and was associated with better motor recovery of hand function.…”

Section: Discussionmentioning

confidence: 60%

“…A stroke in this area is associated with varying degrees of dyskinesia [32]. The NDT-bobath therapy is a prominent method used for rehabilitation training after stroke [33], and it may work by promoting plasticity in the central nervous system.…”

Section: Discussionmentioning

confidence: 99%

Mental Practice Combined with Physical Practice to Enhance Hand Recovery in Stroke Patients

Hua

Song

Zhang

2014

Behavioural Neurology

View full text Add to dashboard Cite

Objectives. To evaluate whether combining mental practice with physical practice training enhances hand function in patients with stroke. Methods. 10 for treatment and 10 for control were recruited for this pre/posttraining matched case control study. In the treatment group, subjects underwent combining mental practice with physical practice for four weeks. In the control group, subjects only participated in physical practice. Change of hand function and the number of activated voxels of the contralateral somatosensory motor cortex (SMC) acquired by functional magnetic resonance imaging were measured. Results. After training, the Action Research Arm Test score increased by 12.65 for treatment and by 5.20 for control. There was a significant difference in the Action Research Arm Test score between the two groups (P = 0.04). The activated voxels number of the contralateral SMC increased in both groups, but the activated voxels number in the contralateral SMC and the improvement of hand function for treatment were greater than for control. In the treatment group, the number of activated voxels of the contralateral SMC was positively correlated with better hand function scores. Conclusions. Combining mental practice with physical practice may be a more effective treatment strategy than physical training alone for hand recovery in stroke patients.

show abstract

Cortical activation in hemianopia after stroke

Cited by 34 publications

References 17 publications

The second face of blindness: Processing speed deficits in the intact visual field after pre- and post-chiasmatic lesions

The second face of blindness: Processing speed deficits in the intact visual field after pre- and post-chiasmatic lesions

“Sightblind”: Perceptual Deficits in the “Intact” Visual Field

Mental Practice Combined with Physical Practice to Enhance Hand Recovery in Stroke Patients

Contact Info

Product

Resources

About