Applying perceptual learning to achieve practical changes in vision

Pretraining alpha rhythm enhancement by neurofeedback facilitates short-term perceptual learning and improves visual acuity by facilitated consolidation

Introduction

Learning through perceptual training using the Gabor patch (GP) has attracted attention as a new vision restoration technique for myopia and age-related deterioration of visual acuity (VA). However, the task itself is monotonous and painful and requires numerous training sessions and some time before being effective, which has been a challenge for its widespread application. One effective means of facilitating perceptual learning is the empowerment of EEG alpha rhythm in the sensory cortex before neurofeedback (NF) training; however, there is a lack of evidence for VA.

Methods

We investigated whether four 30-min sessions of GP training, conducted over 2 weeks with/without EEG NF to increase alpha power (NF and control group, respectively), can improve vision in myopic subjects. Contrast sensitivity (CS) and VA were measured before and after each GP training.

Results

The NF group showed an improvement in CS at the fourth training session, not observed in the control group. In addition, VA improved only in the NF group at the third and fourth training sessions, this appears as a consolidation effect (maintenance of the previous training effect). Participants who produced stronger alpha power during the third training session showed greater VA recovery during the fourth training session.

Discussion

These results indicate that enhanced pretraining alpha empowerment strengthens the subsequent consolidation of perceptual learning and that even a short period of GP training can have a positive effect on VA recovery. This simple protocol may facilitate use of a training method to easily recover vision.

Feature variability determines specificity and transfer in multiorientation feature detection learning

Historically, in many perceptual learning experiments, only a single stimulus is practiced, and learning is often specific to the trained feature. Our prior work has demonstrated that multi-stimulus learning (e.g., training-plus-exposure procedure) has the potential to achieve generalization. Here, we investigated two important characteristics of multi-stimulus learning, namely, roving and feature variability, and their impacts on multi-stimulus learning and generalization. We adopted a feature detection task in which an oddly oriented target bar differed by 16° from the background bars. The stimulus onset asynchrony threshold between the target and the mask was measured with a staircase procedure. Observers were trained with four target orientation search stimuli, either with a 5° deviation (30°-35°-40°-45°) or with a 45° deviation (30°-75°-120°-165°), and the four reference stimuli were presented in a roving manner. The transfer of learning to the swapped target-background orientations was evaluated after training. We found that multi-stimulus training with a 5° deviation resulted in significant learning improvement, but learning failed to transfer to the swapped target-background orientations. In contrast, training with a 45° deviation slowed learning but produced a significant generalization to swapped orientations. Furthermore, a modified training-plus-exposure procedure, in which observers were trained with four orientation search stimuli with a 5° deviation and simultaneously passively exposed to orientations with high feature variability (45° deviation), led to significant orientation learning generalization. Learning transfer also occurred when the four orientation search stimuli with a 5° deviation were presented in separate blocks. These results help us to specify the condition under which multistimuli learning produces generalization, which holds potential for real-world applications of perceptual learning, such as vision rehabilitation and expert training.

Decision-making processes in perceptual learning depend on effectors

Visual perceptual learning is traditionally thought to arise in visual cortex. However, typical perceptual learning tasks also involve systematic mapping of visual information onto motor actions. Because the motor system contains both effector-specific and effector-unspecific representations, the question arises whether visual perceptual learning is effector-specific itself, or not. Here, we study this question in an orientation discrimination task. Subjects learn to indicate their choices either with joystick movements or with manual reaches. After training, we challenge them to perform the same task with eye movements. We dissect the decision-making process using the drift diffusion model. We find that learning effects on the rate of evidence accumulation depend on effectors, albeit not fully. This suggests that during perceptual learning, visual information is mapped onto effector-specific integrators. Overlap of the populations of neurons encoding motor plans for these effectors may explain partial generalization. Taken together, visual perceptual learning is not limited to visual cortex, but also affects sensorimotor mapping at the interface of visual processing and decision making.

Variability in training unlocks generalization in visual perceptual learning through invariant representations

Stimulus and location specificity are long considered hallmarks of visual perceptual learning. This renders visual perceptual learning distinct from other forms of learning, where generalization can be more easily attained, and therefore unsuitable for practical applications, where generalization is key. Based on the hypotheses derived from the structure of the visual system, we test here whether stimulus variability can unlock generalization in perceptual learning. We train subjects in orientation discrimination, while we vary the amount of variability in a task-irrelevant feature, spatial frequency. We find that, independently of task difficulty, this manipulation enables generalization of learning to new stimuli and locations, while not negatively affecting the overall amount of learning on the task. We then use deep neural networks to investigate how variability unlocks generalization. We find that networks develop invariance to the task-irrelevant feature when trained with variable inputs. The degree of learned invariance strongly predicts generalization. A reliance on invariant representations can explain variability-induced generalization in visual perceptual learning. This suggests new targets for understanding the neural basis of perceptual learning in the higher-order visual cortex and presents an easy-to-implement modification of common training paradigms that may benefit practical applications.

Perceptual learning: Breaking specificity by variability

A new psychophysical study in humans suggests that increasing the variability of task-irrelevant features during training enhances the generalization of visual perceptual learning to untrained stimuli and locations.

Effects of Gamification on Assessment of Spatial Release From Masking

PURPOSE

Difficulty understanding speech in noise is a common communication problem. Clinical tests of speech in noise differ considerably from real-world listening and offer patients limited intrinsic motivation to perform well. In order to design a test that captures motivational aspects of real-world communication, this study investigated effects of gamification, or the inclusion of game elements, on a laboratory spatial release from masking test.

METHOD

Fifty-four younger adults with normal hearing completed a traditional laboratory and a gamified test of spatial release from masking in counterbalanced order. Masker level adapted based on performance, with the traditional test ending after 10 reversals and the gamified test ending when participants solved a visual puzzle. Target-to-masker ratio thresholds (TMRs) with colocated maskers, separated maskers, and estimates of spatial release were calculated after the 10th reversal for both tests and from the last six reversals of the adaptive track from the gamified test.

RESULTS

Thresholds calculated from the 10th reversal indicated no significant differences between the traditional and gamified tests. A learning effect was observed with spatially separated maskers, such that TMRs were better for the second test than the first, regardless of test order. Thresholds calculated from the last six reversals of the gamified test indicated better TMRs in the separated condition compared to the traditional test.

CONCLUSIONS

Adding gamified elements to a traditional test of spatial release from masking did not negatively affect test validity or estimates of spatial release. Participants were willing to continue playing the gamified test for an average of 30.2 reversals of the adaptive track. For some listeners, performance in the separated condition continued to improve after the 10th reversal, leading to better TMRs and greater spatial release from masking at the end of the gamified test compared to the traditional test.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22028789.

Reading text works better than watching videos to improve acuity in a simulation of artificial vision

Simulated artificial vision is used in visual prosthesis design to answer questions about device usability. We previously reported a striking increase in equivalent visual acuity with daily use of a simulation of artificial vision in an active task, reading sentences, that required high levels of subject engagement, but passive activities are more likely to dominate post-implant experience. Here, we investigated the longitudinal effects of a passive task, watching videos. Eight subjects used a simulation of a thalamic visual prosthesis with 1000 phosphenes to watch 23 episodes of classic American television in daily, 25-min sessions, for a period of 1 month with interspersed reading tests that quantified reading accuracy and reading speed. For reading accuracy, we found similar dynamics to the early part of the learning process in our previous report, here leading to an improvement in visual acuity of 0.15 ± 0.05 logMAR. For reading speed, however, no change was apparent by the end of training. We found that single reading sessions drove about twice the improvement in acuity of single video sessions despite being only half as long. We conclude that while passive viewing tasks may prove useful for post-implant rehabilitation, active tasks are likely to be preferable.

Change-detection training and its effects on visual processing skills

Previous cognitive training research with the change-detection paradigm found only sparse effects that went beyond improvements in the training task but stressed an increase in fidelity of internal memory representations. Motivated by the demanding visual processing requirements of change-detection training, we extended this work by focusing on whether training on a change-detection task would improve visual processing skills. Fifty participants were randomly assigned to train on a change-detection task or on a control task for seven sessions. Participants' visual processing skills were assessed before and after the intervention, focusing on visual search, contrast sensitivity, and contour integration. Our results suggest a general improvement in perceptual skills that was primarily driven by a conjunction search task and to a much lesser extent by a complex visual search task and a contrast sensitivity task. The data from the conjunction search task further suggest a causal link between training and improvements of perceptual as opposed to attentional processes. Since the change-detection paradigm is commonly used to assess working memory capacity, future research needs to investigate how much of its variance is explained by memory performance and how much is explained by perceptual processes.

Testing the efficacy of vision training for presbyopia: alternating-distance training does not facilitate vision improvement compared to fixed-distance training

PURPOSE

Current evidence demonstrates the effectiveness of vision training for presbyopia. We developed and examined a training program to test the effectiveness of alternating focal distances as a training method.

METHODS

We devised a sharpness discrimination task, in which participants judged whether the stimulus was a sine- or square-wave grating, and tested in two training groups and one control group. In the alternating-distance training group (N = 8, age 49-64), participants had to alternate the fixation between a near- and far-screen. In the fixed-distance training group (N=8, age 47-65), participants fixated on the same-distance target for the whole block. Before and after the 20 training sessions, we measured the near- and far-visual acuity (VA) using the Landolt C and Early Treatment Diabetic Retinopathy Study (ETDRS) tasks and contrast sensitivity using the qCSF procedure. The control group (N=8, age 49-65) participated only in the pre- and post-tests.

RESULTS

Both training groups showed a significant improvement between the pre- and post-tests in the Landolt C task, and the improvement sizes were not significantly different between the groups. In the ETDRS task, only the fixed-distance training group showed significant improvement, although there was no significant difference between the two groups. Neither group showed improvement in the contrast sensitivity task compared to the control group.

CONCLUSION

The novel sharpness discrimination task can be an effective training method for presbyopia to prevent the deterioration of VA; however, contrary to popular belief, the effect of alternating-distance training was comparable to or even weaker than that of fixed-distance training.

Efficacy of Visual Training Program for Students with Visual Impairment

This pilot study investigated the effects of a visual training program for students with low vision. A pre and post design was used. The Beery-Buktenica Developmental Test of Visual-Motor Integration and the Test of Visual-Perceptual Skills were used to assess the perceptual and visual motor skills of fifteen students with low vision. Their mean age was (8.47 ± 1.12); and the mean of their visual acuity of was (0.12 ± 0.11). The three-part intervention program (physical worksheets, a computer-based intervention program, activities of visual perceptual skills) was implemented over four weeks (three sessions/week). Kruskal Wallis tests were used to examine the effect of visual acuity on the progress achieved, and the Wilcoxon-Signed Ranks test was used to identify differences in the scores pre-post intervention. Results showed statistically significant improvement in the visual perceptual and visual-motor integration skills. There was not any statistically significant effect of visual acuity on the progress achieved.

Training with an auditory perceptual learning game transfers to speech in competition

Understanding speech in the presence of acoustical competition is a major complaint of those with hearing difficulties. Here, a novel perceptual learning game was tested for its effectiveness in reducing difficulties with hearing speech in competition. The game was designed to train a mixture of auditory processing skills thought to underlie speech in competition, such as spectral-temporal processing, sound localization, and auditory working memory. Training on these skills occurred both in quiet and in competition with noise. Thirty college-aged participants without any known hearing difficulties were assigned either to this mixed-training condition or an active control consisting of frequency discrimination training within the same gamified setting. To assess training effectiveness, tests of speech in competition (primary outcome), as well as basic supra-threshold auditory processing and cognitive processing abilities (secondary outcomes) were administered before and after training. Results suggest modest improvements on speech in competition tests in the mixed-training compared to the frequency-discrimination control condition (Cohen’s d = 0.68). While the sample is small, and in normally hearing individuals, these data suggest promise of future study in populations with hearing difficulties.

Broad and Long-Lasting Vision Improvements in Youth With Infantile Nystagmus After Home Training With a Perceptual Learning App

Current treatments for infantile nystagmus (IN), focused on dampening the oscillating eye movements, yield little to no improvement in visual functioning. It makes sense, however, to treat the visual impairments associated with IN with tailored sensory training. Recently, we developed such a training, targeting visual crowding as an important bottleneck in visual functioning with an eye-movement engaging letter discrimination task. This training improved visual performance of children with IN, but most children had not reached plateau performance after 10 supervised training sessions (3,500 trials). Here, we evaluate the effects of prolonged perceptual learning (14,000 trials) in 7-18-year-old children with IN and test the feasibility of tablet-based, at-home intervention. Results demonstrate that prolonged home-based perceptual training results in stable, long lasting visual acuity improvements at distance and near, with remarkably good transfer to reading and even stereopsis. Improvements on self-reported functional vision scores underline the clinical relevance of perceptual learning with e-health apps for individuals with IN.

Individual difference predictors of learning and generalization in perceptual learning

Given appropriate training, human observers typically demonstrate clear improvements in performance on perceptual tasks. However, the benefits of training frequently fail to generalize to other tasks, even those that appear similar to the trained task. A great deal of research has focused on the training task characteristics that influence the extent to which learning generalizes. However, less is known about what might predict the considerable individual variations in performance. As such, we conducted an individual differences study to identify basic cognitive abilities and/or dispositional traits that predict an individual's ability to learn and/or generalize learning in tasks of perceptual learning. We first showed that the rate of learning and the asymptotic level of performance that is achieved in two different perceptual learning tasks (motion direction and odd-ball texture detection) are correlated across individuals, as is the degree of immediate generalization that is observed and the rate at which a generalization task is learned. This indicates that there are indeed consistent individual differences in perceptual learning abilities. We then showed that several basic cognitive abilities and dispositional traits are associated with an individual's ability to learn (e.g., simple reaction time; sensitivity to punishment) and/or generalize learning (e.g., cognitive flexibility; openness to experience) in perceptual learning tasks. We suggest that the observed individual difference relationships may provide possible targets for future intervention studies meant to increase perceptual learning and generalization.

Development and Evaluation of a Visual Remediation Intervention for People with Schizophrenia

It is now well documented that schizophrenia is associated with impairments in visual processing at all levels of vision, and that these disturbances are related to deficits in multiple higher-level cognitive and social cognitive functions. Visual remediation methods have been slow to appear in the literature as a potential treatment strategy to target these impairments, however, in contrast to interventions that aim to improve auditory and higher cognitive functions in schizophrenia. In this report, we describe a National Institute of Mental Health (NIMH)-funded R61/R33 grant that uses a phased approach to optimize and evaluate a novel visual remediation intervention for people with schizophrenia. The goals of this project are: (1) in the R61 phase, to establish the optimal components and dose (number of sessions) of a visual remediation intervention from among two specific visual training strategies (and their combination) for improving low and mid-level visual functions in schizophrenia; and (2) in the R33 phase, to determine the extent to which the optimal intervention improves not only visual processing but also higher-level cognitive and role functions. Here we present the scientific background for and innovation of the study, along with our methods, hypotheses, and preliminary data. The results of this study will help determine the utility of this novel intervention approach for targeting visual perceptual, cognitive, and functional impairments in schizophrenia.

Perceptual Learning of Appendicitis Diagnosis in Radiological Images

A sizeable body of work has demonstrated that participants have the capacity to show substantial increases in performance on perceptual tasks given appropriate practice. This has resulted in significant interest in the use of such perceptual learning techniques to positively impact performance in real-world domains where the extraction of perceptual information in the service of guiding decisions is at a premium. Radiological training is one clear example of such a domain. Here we examine a number of basic science questions related to the use of perceptual learning techniques in the context of a radiology-inspired task. On each trial of this task, participants were presented with a single axial slice from a CT image of the abdomen. They were then asked to indicate whether or not the image was consistent with appendicitis. We first demonstrate that, although the task differs in many ways from standard radiological practice, it nonetheless makes use of expert knowledge, as trained radiologists who underwent the task showed high (near ceiling) levels of performance. Then, in a series of four studies we show that (1) performance on this task does improve significantly over a reasonably short period of training (on the scale of a few hours); (2) the learning transfers to previously unseen images and to untrained image orientations; (3) purely correct/incorrect feedback produces weak learning compared to more informative feedback where the spatial position of the appendix is indicated in each image; and (4) there was little benefit seen from purposefully structuring the learning experience by starting with easier images and then moving on to more difficulty images (as compared to simply presenting all images in a random order). The implications for these various findings with respect to the use of perceptual learning techniques as part of radiological training are then discussed.

Specificity and retention of visual perceptual learning in young children with low vision

There is evidence that a pen-and-paper training based on perceptual learning principles improves near visual acuity in young children with visual impairment. The aim of the present study is to measure specificity and retention of its training effects during one year. Sixteen visually impaired children aged 4-8 years were divided in two age- and acuity-matched groups: an early (n = 9) and late treatment group (n = 7). Training consisted of 12 sessions (2× per week for 6 weeks). Studied variables were uncrowded and crowded binocular near visual acuity (40 cm), distance visual acuity (3.0 m) and fine motor skills (Beery VMI, subtest Motor Control). In the early treatment group, we measured at 0 months (pre-training), at 2 months (post-training), at 8 months (6 months post-training) and at 14 months (12 months post-training) since inclusion. In the late treatment group, three pre-training measurements were performed at 0, 2 and 8 months, and two measurements at 0 and 6 months post-training. In the short term, training improved uncrowded and crowded near visual acuity at 0.4 m by 0.13 ± 0.03 and 0.09 ± 0.03 logMAR, respectively (mean ± SEM). Training did not affect distance acuities or Beery scores. Learning effects on uncrowded and crowded near visual acuities remained intact 6-12 months after training. We conclude that the pen-and-paper training specifically improves near visual acuities but does not transfer to distance acuities or fine motor skills. Improvements in near visual acuity are retained over time, bolstering its clinical value.

Short-term Perceptual Learning Game Does Not Improve Patching-Resistant Amblyopia in Older Children

PURPOSE

To investigate self-administered, at-home use of a perceptual learning-based video game consisting of target detection of stimuli in different sizes, spatial frequency, orientation, and contrast as a potential dichoptic therapy to improve binocular function in amblyopic patients resistant to patching.

METHODS

Children (ages 8 to 18 years) with strabismic and/or anisometropic amblyopia were recruited from a single institution. All participants (n = 25) were prescribed 6 weeks of patching for 2 hours per day, and those whose visual acuity did not improve were randomized to binocular perceptual learning (n = 7), monocular perceptual learning (n = 8), or patching (n = 10) groups for 8 weeks in this prospective cohort study. After an 8-week long period of treatment cessation, during which participants stopped patching or perceptual learning, participants in the patching group were randomized to binocular or monocular perceptual learning training; those in the perceptual learning groups remained the same. Visual function was assessed by visual acuity, low contrast acuity, reading speed, stereoacuity, and binocularity; compliance was evaluated by exercise logs.

RESULTS

There were no significant improvements in visual function parameters, which did not vary by treatment group. However, some visual outcomes, such as binocular summation and reading speed, correlated positively with compliance to perceptual learning therapy.

CONCLUSIONS

At-home, self-administered use of this perceptual learning-based video game-based visual training does not consistently add therapeutic benefit to those with amblyopia resistant to patching. Future investigation is required to determine whether methods to increase compliance will lead to more reliable outcomes. [J Pediatr Ophthalmol Strabismus. 2020;57(3):176-184.].

The assistance of electronic visual aids with perceptual learning for the improvement in visual acuity in visually impaired children

PURPOSE

To investigate the effect of electronic visual aids (EVA) combined with perceptual learning (PL) for the improvement in visual acuity for moderate to severe visually impaired and blind children.

METHODS

Twenty-eight 6- to 14-year-old visually impaired children (19 boys and 9 girls) were divided into two groups: PL under the assistance of EVA (Group A, 14 children) and simple PL without EVA (Group B, 14 children). The content of PL was to search the inversed "E" in the crowding strings and connected with lines, 30 minutes a day for 6 months. EVA can provide 5-10 times magnification on the 4.3-inch screen. Uncorrected distance visual acuity (UCVA), best-corrected visual acuity (BCVA), near visual acuity (NVA) and refractive error were evaluated before and 3 and 6 months after training.

RESULTS

Baseline UCVA, BCVA or NVA was comparable between the two groups. Three months after training, UCVA, BCVA and NVA improved significantly in Group A (p < 0.05). At the end of training, UCVA and BCVA continued progressing in Group A compared to 3 months (p = 0.01, 0.02), but visual acuity did not show significant improvement in Group B during the same time, except that UCVA improved at the first follow-up. Refractive error had no significant change post-training in both groups.

CONCLUSIONS

Visually impaired children can benefit more from the combination of PL with EVA than simple PL, and the improvement in visual acuity accompanied no significant myopic shift. It may provide a new method of treatment and rehabilitation in visually impaired children.

The Potential of Virtual Reality for Inducing Neuroplasticity in Children with Amblyopia

In recent years, virtual reality (VR) has emerged as a new safe and effective tool for neurorehabilitation of different childhood and adulthood conditions. VR-based therapies can induce cortical reorganization and promote the activation of different neuronal connections over a wide range of ages, leading to contrasted improvements in motor and functional skills. The use of VR for the visual rehabilitation in amblyopia has been investigated in the last years, with the potential of using serious games combining perceptual learning and dichoptic stimulation. This combination of technologies allows the clinician to measure, treat, and control changes in interocular suppression, which is one of the factors leading to cortical alterations in amblyopia. Several clinical researches on this issue have been conducted, showing the potential of promoting visual acuity, contrast sensitivity, and stereopsis improvement. Indeed, several systems have been evaluated for amblyopia treatment including the use of different commercially available types of head mounted displays (HMDs). These HMDs are mostly well tolerated by patients during short exposures and do not cause significant long-term side effects, although their use has been occasionally associated with some visual discomfort and other complications in certain types of subjects. More studies are needed to confirm these promising therapies in controlled randomized clinical trials, with special emphasis on the definition of the most adequate planning for obtaining an effective recovery of the visual and binocular function.

An investigation of far and near transfer in a gamified visual learning paradigm

After training, visual perceptual learning improvements are mostly constrained to the trained stimulus feature and retinal location. The aim of this study is to construct an integrated paradigm where the visual learning happens in a more natural context and in parallel for multiple stimulus types, and to test the generalization of learning-related improvements towards untrained features, locations, and more general cognitive domains. Half the subjects were trained with a gamified perceptual learning paradigm for ten hours, which consisted of an orientation discrimination task and a novel object categorization task embedded in a three-dimensional maze. A second group of subjects, an active control group, played ten hours of Candy Crush Saga. Before and after training, all subjects completed a 'near transfer' orientation discrimination and novel object categorization task, as well as a set of 'far transfer' general cognitive and attentional tasks. During the perceptual learning tasks, two different stimulus features and two retinal location pairs were assessed in each task. For the experimental group, one stimulus feature and retinal location pair was trained, whilst the other one remained untrained. Both features and location pairs were untrained in the control group. Far transfer did occur in some domains across all subjects irrespective of the training regimen (i.e. executive functioning, mental rotation performance, and multitask performance and speed). Near transfer was present in both groups, however only more pronounced for one particular task in the experimental group, namely novel object categorization. To conclude, all but one near transfer task did not generalize more than the control group.

Perceptual learning while preparing saccades

Traditional perceptual learning protocols rely almost exclusively on long periods of uninterrupted fixation. Taking a first step towards understanding perceptual learning in natural vision, we had observers report the orientation of a briefly flashed stimulus (clockwise or counterclockwise from a reference orientation) presented strictly during saccade preparation at a location offset from the saccade target. For each observer, the saccade direction, stimulus location, and orientation remained the same throughout training. Subsequently, we assessed performance during fixation in three transfer sessions, either at the trained or at an untrained location, and either using an untrained (Experiment 1) or the trained (Experiment 2) stimulus orientation. We modeled the evolution of contrast thresholds (i.e., the stimulus contrast necessary to discriminate its orientation correctly 75% of the time) as an exponential learning curve, and quantified departures from this curve in transfer sessions using two new, complementary measures of transfer costs (i.e., performance decrements after the transition into the Transfer phase). We observed robust perceptual learning and associated transfer costs for untrained locations and orientations. We also assessed if spatial transfer costs were reduced for the remapped location of the pre-saccadic stimulus-the location the stimulus would have had (but never had) after the saccade. Although the pattern of results at that location differed somewhat from that at the control location, we found no clear evidence for perceptual learning at remapped locations. Using novel, model-based ways to assess learning and transfer costs, our results show that location and feature specificity, hallmarks of perceptual learning, subsist if the target stimulus is presented strictly during saccade preparation throughout training.

A new framework of design and continuous evaluation to improve brain training

Effective teaching critically relies upon effective evaluation because evaluation is required to gain understanding of existing abilities and, in turn, determine learning outcomes. Methods of effective evaluation are surprisingly elusive in many fields and this limits our understanding of which training methods are truly effective. In the present article, issues of effective evaluation are discussed in the context of "brain training," an exciting but much criticized field. Problems in test validity in the field of brain training, parallel those in many other fields; such as deficiencies in test reliability, teaching to the test, expectation effects, as well as statistical rigor. Here we review these issues and discuss how commonalities between the goals of evaluation and adaptive training procedures suggest a new paradigm that synthesizes evaluation and training. We suggest that continuous evaluation, where testing is integrated into the training, may provide a path towards greater reliability of skill evaluation, through longitudinal sampling, and validity, through better alignment of evaluation activities in respect to learning objectives.

Audiomotor Perceptual Training Enhances Speech Intelligibility in Background Noise

Sensory and motor skills can be improved with training, but learning is often restricted to practice stimuli. As an exception, training on closed-loop (CL) sensorimotor interfaces, such as action video games and musical instruments, can impart a broad spectrum of perceptual benefits. Here we ask whether computerized CL auditory training can enhance speech understanding in levels of background noise that approximate a crowded restaurant. Elderly hearing-impaired subjects trained for 8 weeks on a CL game that, like a musical instrument, challenged them to monitor subtle deviations between predicted and actual auditory feedback as they moved their fingertip through a virtual soundscape. We performed our study as a randomized, double-blind, placebo-controlled trial by training other subjects in an auditory working-memory (WM) task. Subjects in both groups improved at their respective auditory tasks and reported comparable expectations for improved speech processing, thereby controlling for placebo effects. Whereas speech intelligibility was unchanged after WM training, subjects in the CL training group could correctly identify 25% more words in spoken sentences or digit sequences presented in high levels of background noise. Numerically, CL audiomotor training provided more than three times the benefit of our subjects' hearing aids for speech processing in noisy listening conditions. Gains in speech intelligibility could be predicted from gameplay accuracy and baseline inhibitory control. However, benefits did not persist in the absence of continuing practice. These studies employ stringent clinical standards to demonstrate that perceptual learning on a computerized audio game can transfer to "real-world" communication challenges.

[Improvement of vision through perceptual learning in the case of refractive errors and presbyopia : A critical valuation]

The idea of compensating or even rectifying refractive errors and presbyopia with the help of vision training is not new. For most approaches, however, scientific evidence is insufficient. A currently promoted method is "perceptual learning", which is assumed to improve stimulus processing in the brain. The basic phenomena of perceptual learning have been demonstrated by a multitude of studies. Some of these specifically address the case of refractive errors and presbyopia. However, many open questions remain, in particular with respect to the transfer of practice effects to every-day vision. At present, the method should therefore be judged with caution.

Enhancement of motor skill learning by a combination of ideal model-observation and self-observation

[Purpose] In sports physical therapy, video of a patient’s movement or of a skilled model’s movement has been used as observational learning methods for injury prevention and movement modification. Positive effects of model video observation have been reported. This study aimed to clarify the effect on motor skill learning using a combination of model-observation and self-observation, which is thought to act as an enhanced method for active error detection by comparing model-observation and self-observation alone for acquisition of correct sports movement. [Subjects and Methods] Forty-five healthy females were randomly allocated into three groups comprising model- and self-observation, model-observation, and self-observation. The motor task performed was a half golf swing using an elastic club. Shoulder grip angle between both shoulder lines and the acromia grip strength were measured as an index of body rotation using a three-dimensional motion analyzer. Change in the shoulder grip angle in the three groups was analyzed at pre-, immediate delayed retention, and delayed retention tests. [Results] A significant difference in shoulder grip angle was observed among the three groups for the immediate delayed retention test. The combined model and self-observation group had a value closer to 90 degrees compared to the other two groups. [Conclusion] Observation combining model and self-observation exerted a positive effect on short-term motor skill learning.

Visual perceptual remediation for individuals with schizophrenia: Rationale, method, and three case studies

OBJECTIVE

Few studies have evaluated the effects of visual remediation strategies in schizophrenia despite abundant evidence of visual-processing alterations in this condition. We report preliminary, case-study-based evidence regarding the effects of visual remediation in this population.

METHOD

We describe implementation of a visual-perceptual training program called ULTIMEYES (UE) and initial results through 3 brief case studies of individuals with schizophrenia. UE targets broad-based visual function, including low-level processes (e.g., acuity, contrast sensitivity) as well as higher level visual functions. Three inpatients, recruited from a research unit, participated in at least 38 sessions 3 to 4 times per week for approximately 25 min per session. Contrast sensitivity (a trained task), as well as acuity and perceptual organization (untrained tasks), were assessed before and after the intervention. Levels of progression through the task are also reported.

RESULTS

UE was well tolerated by the participants and led to improvements in contrast sensitivity, as well as more generalized gains in visual acuity in all 3 participants and perceptual organization in 2 participants. Symptom profiles were somewhat different for each participant, but all were symptomatic during the intervention. Despite this, they were able to focus on and benefit from training. The adaptive nature of the training was well suited to the slower progression of 2 participants.

CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

These case studies set the stage for further research, such as larger, randomized controlled trials of the intervention that include additional assessments of perceptual function and measures of cognition, social cognition, and functional outcomes. (PsycINFO Database Record

Two Visual Training Paradigms Associated with Enhanced Critical Flicker Fusion Threshold

Critical flicker fusion thresholds (CFFTs) describe when quick amplitude modulations of a light source become undetectable as the frequency of the modulation increases and are thought to underlie a number of visual processing skills, including reading. Here, we compare the impact of two vision-training approaches, one involving contrast sensitivity training and the other directional dot-motion training, compared to an active control group trained on Sudoku. The three training paradigms were compared on their effectiveness for altering CFFT. Directional dot-motion and contrast sensitivity training resulted in significant improvement in CFFT, while the Sudoku group did not yield significant improvement. This finding indicates that dot-motion and contrast sensitivity training similarly transfer to effect changes in CFFT. The results, combined with prior research linking CFFT to high-order cognitive processes such as reading ability, and studies showing positive impact of both dot-motion and contrast sensitivity training in reading, provide a possible mechanistic link of how these different training approaches impact reading abilities.

Transfer in Rule-Based Category Learning Depends on the Training Task

While learning is often highly specific to the exact stimuli and tasks used during training, there are cases where training results in learning that generalizes more broadly. It has been previously argued that the degree of specificity can be predicted based upon the learning solution(s) dictated by the particular demands of the training task. Here we applied this logic in the domain of rule-based categorization learning. Participants were presented with stimuli corresponding to four different categories and were asked to perform either a category discrimination task (which permits learning specific rule to discriminate two categories) or a category identification task (which does not permit learning a specific discrimination rule). In a subsequent transfer stage, all participants were asked to discriminate stimuli belonging to two of the categories which they had seen, but had never directly discriminated before (i.e., this particular discrimination was omitted from training). As predicted, learning in the category-discrimination tasks tended to be specific, while the category-identification task produced learning that transferred to the transfer discrimination task. These results suggest that the discrimination and identification tasks fostered the acquisition of different category representations which were more or less generalizable.

Integrating oculomotor and perceptual training to induce a pseudofovea: A model system for studying central vision loss

People with a central scotoma often adopt an eccentric retinal location (Preferred Retinal Locus, PRL) for fixation. Here, we proposed a novel training paradigm as a model system to study the nature of the PRL formation and its impacts on visual function. The training paradigm was designed to effectively induce a PRL at any intended retinal location by integrating oculomotor control and pattern recognition. Using a gaze-contingent display, a simulated central scotoma was induced in eight normally sighted subjects. A subject's entire peripheral visual field was blurred, except for a small circular aperture with location randomly assigned to each subject (to the left, right, above, or below the scotoma). Under this viewing condition, subjects performed a demanding oculomotor and visual recognition task. Various visual functions were tested before and after training at both PRL and nonPRL locations. After 6-10 hr of the training, all subjects formed their PRL within the clear window. Both oculomotor control and visual recognition performance significantly improved. Moreover, there was considerable improvement at PRL location in high-level function, such as trigram letter-recognition, reading, and spatial attention, but not in low-level function, such as acuity and contrast sensitivity. Our results demonstrated that within a relatively short time, a PRL could be induced at any intended retinal location in normally-sighted subjects with a simulated scotoma. Our training paradigm might not only hold promise as a model system to study the dynamic nature of the PRL formation, but also serve as a rehabilitation regimen for individuals with central vision loss.

Is improved contrast sensitivity a natural consequence of visual training?

Many studies have shown that training and testing conditions modulate specificity of visual learning to trained stimuli and tasks. In visually impaired populations, generalizability of visual learning to untrained stimuli/tasks is almost always reported, with contrast sensitivity (CS) featuring prominently among these collaterally-improved functions. To understand factors underlying this difference, we measured CS for direction and orientation discrimination in the visual periphery of three groups of visually-intact subjects. Group 1 trained on an orientation discrimination task with static Gabors whose luminance contrast was decreased as performance improved. Group 2 trained on a global direction discrimination task using high-contrast random dot stimuli previously used to recover motion perception in cortically blind patients. Group 3 underwent no training. Both forms of training improved CS with some degree of specificity for basic attributes of the trained stimulus/task. Group 1's largest enhancement was in CS around the trained spatial/temporal frequencies; similarly, Group 2's largest improvements occurred in CS for discriminating moving and flickering stimuli. Group 3 saw no significant CS changes. These results indicate that CS improvements may be a natural consequence of multiple forms of visual training in visually intact humans, albeit with some specificity to the trained visual domain(s).

The Impacts of Video Games on Cognition (and How the Government Can Guide the Industry)

Video game play has become a pervasive part of American culture. The dramatic increase in the popularity of video games has resulted in significant interest in the effects that video gaming may have on the brain and behavior. The scientific research to date indicates that some, but not all, commercial video games do indeed have the potential to cause large-scale changes in a wide variety of aspects of human behavior, including the focus of this review—cognitive abilities. More recent years have seen the rise of a separate form of video games, the so-called “brain games,” or games designed with the explicit goal of enhancing cognitive abilities. Although research on such brain games is still in its infancy, and the results have definitely not been uniformly positive, there is nonetheless reason for continued optimism that custom games can be developed that make a lasting and positive impact on human cognitive skills. Here, we discuss the current state of the scientific literature surrounding video games and human cognition with an emphasis on points critically related to public policy.

Behavioral training to improve collision detection

Young drivers are a high-risk group for vehicle crashes due to inexperience in detecting an impending collision and are one group that may benefit from perceptual learning (PL) training. The present study assessed whether PL could be used to improve performance in collision detection. Ten college-aged subjects participated in the first experiment, which consisted of seven 1-hr sessions conducted on separate days. Thresholds at three observer/object speeds were measured prior to training using a two-alternative forced choice procedure during which they indicated whether an approaching object would result in a collision or noncollision event. Participants were then trained near threshold at one of these speeds for 5 days. After training, participants showed a significant reduction in the time needed to detect a collision at the trained speed. This improvement was also found to transfer to the higher observer speed condition. A second experiment was conducted to determine whether this improvement was due to training near threshold or whether this improvement was merely due to practice with the task. Training with stimuli well above threshold showed no significant improvement in performance, indicating that the improvement seen in the first experiment was not solely due to task practice.

Mapping the structure of perceptual and visual-motor abilities in healthy young adults

The ability to quickly detect and respond to visual stimuli in the environment is critical to many human activities. While such perceptual and visual-motor skills are important in a myriad of contexts, considerable variability exists between individuals in these abilities. To better understand the sources of this variability, we assessed perceptual and visual-motor skills in a large sample of 230 healthy individuals via the Nike SPARQ Sensory Station, and compared variability in their behavioral performance to demographic, state, sleep and consumption characteristics. Dimension reduction and regression analyses indicated three underlying factors: Visual-Motor Control, Visual Sensitivity, and Eye Quickness, which accounted for roughly half of the overall population variance in performance on this battery. Inter-individual variability in Visual-Motor Control was correlated with gender and circadian patters such that performance on this factor was better for males and for those who had been awake for a longer period of time before assessment. The current findings indicate that abilities involving coordinated hand movements in response to stimuli are subject to greater individual variability, while visual sensitivity and occulomotor control are largely stable across individuals.