Prism Adaptation Improves Chronic Visual and Haptic Neglect: A Single Case Study

doi:10.1016/S0010-9452(08)70662-2

Cortex

Volume 38, Issue 3, 2002, Pages 309-320

https://doi.org/10.1016/S0010-9452(08)70662-2 Get rights and content

Abstract

Visuomotor adaptation to rightward displacing optical prisms is known to induce temporary improvements in the symptoms of left visual neglect. We report a 74 year-old woman with severe and chronic neglect of nine months duration, who underwent three weekly sessions of prism adaptation. Substantial improvements were obtained on tests of visual neglect (cancellation, copying and bisection). Improvement was also observed on a spatial judgement task, with no explicit visual component, in which CS was required to locate the centre of a haptically explored circle. These observations confirm that brief periods of prism exposure can benefit even chronic neglect disorders. Moreover, the improvement observed on the haptic task supports the belief that this procedure can influence higher levels of spatial representation.

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Cited by (126)

Unconventionally trendy: The pluralistic endeavour of Cortex into the human cognitive neurosciences
2024, Cortex
A registered re-examination of the effects of leftward prism adaptation on landmark judgements in healthy people
2023, Cortex
Citation Excerpt :
Neglect is a pathological imbalance of spatial attention, cognition and behaviour, associated with damage to the right hemisphere, often following stroke. The amelioration of these symptoms far outlasted the expected sensorimotor aftereffects, persisting for hours and even days after prism exposure (McIntosh, Rossetti, & Milner, 2002; Rossetti et al., 1998). Moreover, the benefits were found to generalise to a range of visuospatial tasks (for a review, see Pisella, Rode, Farnè, Tilikete, & Rossetti, 2006), and to non-visual tasks based on haptic exploration (McIntosh et al., 2002) and mental representation (Rode, Rossetti, & Boisson, 2001; Rossetti et al., 2004).
It has long been known that active adaptation to a shift of the visual field, caused by laterally-displacing prisms, induces short-term sensorimotor aftereffects. More recent evidence suggests that prism adaptation may also stimulate higher-level changes in spatial cognition, which can modify the spatial biases of healthy people. The first reported, and most replicated, higher-level aftereffect is a rightward shift in the point of subjective equality (PSE) for a perceptual bisection task (the landmark task), following adaptation to leftward prisms. A recent meta-analysis suggests that this visuospatial aftereffect should be robustly induced by an extended period of adaptation to strong leftward prisms (15°, ∼26.8 prism dioptres). However, we have been unable to replicate this effect, suggesting that the effect size estimated from prior literature might be over-optimistic. This Registered Report compared visuospatial aftereffects on the landmark task for a 15° leftward prism adaptation group (n = 102) against a sham-adaptation control group (n = 102). The effect size for the comparison was Cohen's d = .27, 95% CI [-.01, .55], which did not pass the criterion set for significance. A Bayesian analysis indicated that the data were more than 4.1 times as likely under the null than under an informed experimental hypothesis. Exploratory analyses showed no evidence for a rightward shift of landmark judgements in the prism group considered alone, and no relationship between sensorimotor and visuospatial aftereffects. We further found no support for previous suggestions that visuospatial aftereffects are modulated by a person's baseline bias (leftward or rightward) for the landmark task. Null findings are also presented for a preliminary group of 62 participants adapted to 15° leftward prisms, and an additional group of 29 participants adapted to 10° leftward prisms. We do not rule out the possibility that leftward prisms might induce higher-level visuospatial aftereffects in healthy people, but we should be more sceptical about this claim.
Prisms adaptation improves haptic object discrimination in hemispatial neglect
2020, Cortex
Citation Excerpt :
However, our task was performed with the right hand, for which tactile perception remains unimpaired (Maravita et al., 2003) due to the integration of the somatosensory inputs in the healthy left hemisphere. Previous studies investigating eye or hand exploratory movements revealed a partially left space exploration in RBD+ (De Renzi et al., 1970; Karnath & Fetter, 1995; McIntosh et al., 2002; Revol, 2000). As our haptic-task discrimination task was very close to the sagittal plane, no incomplete object exploration was expected, and nor was it observed.
Neglect manifestations are typically explored in the visual modality. Although they are less commonly investigated tactile deficits also exist, and the aim of this study was to explore neglect in this modality. A haptic object discrimination task was designed to assess whether or not shape perception is impaired in seven right brain damaged patients with or without neglect. Each patient's performance on the object discrimination task was assessed before and after a brief period of prism adaptation, a bottom-up rehabilitation technique known to improve neglect symptoms. The results suggest that a haptic deficit – in the form of substantially more left errors – is present only in patients with neglect. Following prism adaptation, the left bias error rates in neglect patients were substantially reduced, and were similar to those observed in patients without neglect. Moreover, the haptic processing of the right side of objects also improved slightly. This finding suggests an expansion of the effects of prism adaptation to the unexposed, tactile modality supporting the cross-modal central effect hypothesis.
A home-based prism adaptation training for neglect patients
2020, Cortex
Spatial neglect is a debilitating disorder frequently observed after damage to the right cerebral hemisphere. Previous investigations have revealed that prism adaptation (PA) therapy can lead to improvements in neglect-related symptoms. In the typical PA protocol patients repeatedly point toward a visual target while wearing prism goggles. A few years ago, a novel PA procedure, involving a variety of more “ecological” visuo-motor activities during adaptation, less repetitive than a sequence of pointings, was introduced by our research group, and shown to be able to improve neglect-related symptoms to the same extent as the standard pointing task. The ecological procedure was easy to administer and pleasant for the patients. In all previous studies, patients were treated by specialized personnel during hospitalization. In the current study, we investigated the effectiveness of the ecological PA method when performed in a home-based setting, with the help of caregivers and family members. Seven right-brain-damaged patients with chronic left spatial neglect underwent a two-week ecological PA treatment, extended, for two extra weeks, in 6 patients, who were available for this additional rehabilitation session. As a control treatment, patients performed the same activities while wearing neutral goggles, before the PA procedure. Two weeks of ecological PA training proved to be able to significantly improve performance in neuropsychological tests (BIT, Cancellation tasks), a neurological scale (NIH), and functional abilities (CBS), when compared to both the baseline and the neutral control treatment, with improvements being maintained over 6 months. The ecological home-based PA training is effective in alleviating signs of spatial neglect. Importantly, this training is affordable, pleasant, and feasible to be performed in the comfort of the patient's home. Easily extendable to larger patient populations and prolonged periods, this method has a real potential to benefit the quality of life of brain-damaged patients with left spatial neglect.
Wearing prisms to hear differently: After-effects of prism adaptation on auditory perception
2019, Cortex
Citation Excerpt :
Prism adaptation has a strong impact on space representation whatever the dimension of the space, peripersonal (Colent et al., 2000; Michel, Pisella, et al., 2003), extrapersonal (Berberovic & Mattingley, 2003; Michel et al., 2008), or bodily (Michel, Rossetti, et al., 2003), and whatever the spatial nature of the task, direct as in line bisection (e.g., Michel, Pisella, et al., 2003), or with association as in mental numbers (Loftus et al., 2008), or letter scales (Nicholls et al., 2008). The influence of prism adaptation also extends to other cognitive processes such as spatial attention (e.g., Loftus, Vijayakumar, & Nicholls, 2009), hierarchical processing (Bultitude & Woods, 2010; Reed & Dassonville, 2014), and even on cross-modal functions independent from sensorimotor processes involved in visuomanual adaptation such as haptic tasks (McIntosh, Rossetti, & Milner, 2002), tactile extinction (Maravita et al., 2003), tactile threshold and proprioceptive perception (Dijkerman, Webeling, ter Wal, Groet, & van Zandvoort, 2004) and pain perception (Sumitani et al., 2007). To illustrate cross-modal effects of prism exposure, it could be mentioned that neglect occurs throughout auditory manifestations as rightward bias in sound location or dichotic listening (e.g., Bellmann, Meuli, & Clarke, 2001), rightward shift in auditory subjective straight ahead (e.g., Kerkhoff, Artinger, & Ziegler, 1999), and that prism can improve neglect at auditory level (Jacquin-Courtois et al., 2010).
Numerous studies showed that, after adaptation to a leftward optical deviation, pseudoneglect behavior (overrepresentation of the left part compared to the right part of the space) becomes neglect-like behavior (overrepresentation of the right part compared to the left part of the space). Cognitive after-effects have also been shown in cognitive processes that are not intrinsically spatial in nature, but show spatial association as numbers or letters. The space-auditory frequency association (with low frequencies on the left and high frequencies on the right) raises the question of whether prism adaptation can produce after-effects on auditory perception. We used a new experimental protocol, named the ‘auditory interval bisection judgment’, where participants had to estimate what limit of an auditory interval (low or high) a target frequency was closer to. We calculated the subjective auditory interval center. In pretest, there was a spontaneous bias of the subjective center of the auditory interval toward the lower limit. That was the first demonstration of pseudoneglect behavior in auditory frequency representation. ANOVA realized on all participants did not show significant results of prism adaptation, but a posteriori analyses on musicians showed that, after adaptation to a leftward optical deviation, there were more target frequencies perceived as closer to the lower limit of the auditory interval. This result corroborates the shift of the subjective center of the auditory interval toward high frequency limit. These innovative results are discussed in terms of putative neural substrates underpinning the transfer of visuomotor plasticity to auditory frequency perception.
Effect of prism adaptation on neglect hemianesthesia
2019, Cortex
Prism adaptation (PA) has proven to be effective in alleviating many signs of unilateral spatial neglect (USN). Generally, the principal improvement after PA treatment was found to be in the high-level cognitive function. Nevertheless, some evidence has also been found for it in somatosensory function. We have aimed to test the influence of PA on neglect hemianesthesia, a condition in which the high-level neglect-related deficit mimics hemianesthesia. Twenty-one USN patients were enrolled in the study. Each patient performed two sessions of PA, one with neutral glasses and one with prism glasses using a cross-over design. Sensitivity on the upper limb was tested using two methods. The first task was the sensibility subtest which was derived from the standard clinical examination. The second was the perceptual and motor electro-cutaneous threshold on the forearms using an electro-cutaneous stimulator. Four neuropsychological tests were used to diagnose USN and to check improvement: Star cancellation, Line bisection, Sentence reading and the Comb & Razor test. Comparing prism with sham conditions, our results show significant improvements in double extinction and in the electro-cutaneous perceptual threshold only for the contralesional hand. No improvement was found for the ipsilesional hand, for the motor threshold, and for neutral glasses. Significant improvement was found in personal neglect. Replication of the task in a subgroup of patients confirmed the primary results. The improvements in somatosensory perception together with the amelioration of personal neglect suggest that PA also has a specific effect on the neglect hemianesthesia.

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Prism Adaptation Improves Chronic Visual and Haptic Neglect: A Single Case Study

Abstract

Cortex

Archives of Physical Medicine and Rehabilitation

Neuropsychologia

Cortex

Neuropsychologia;

Neuropsychologia

Trends in Cognitive Sciences

A simple test of visual neglect

Neurology

The Complete Works of Lewis Carroll

Recovery from visuospatial neglect in stroke patients

Journal of Neurology, Neurosurgery and Psychiatry

The dissociation of visuospatial neglect and neglect dyslexia

Journal of Neurology, Neurosurgery, and Psychiatry

Unilateral spatial neglect and recovery from hemiplegia: A follow-up study

Brain

“Neglect dyslexia” and the early visual processing of letters in words and nonwords

Cognitive Neuropsychology

Neglect and visual language