Prism Adaptation Research Articles

Modulation of memory by prism adaptation in healthy subjects

Recent findings suggest that prism adaptation can extend its effects beyond spatial attention, modulating the performance of different cognitive tasks by acting on cerebellar, parietal and temporal-frontal networks. We tested groups of healthy subjects to investigate the effects of rightward vs. leftward prism adaptation vs. neutral lenses exposure in a series of memory tasks, probing either short-term (Digit span, Corsi span) or long-term memory (Supraspan verbal and spatial learning). In the short-term memory tasks, leftward prism adaptation selectively increased verbal span, while rightward prism adaptation increased spatial span. In the long-term memory tasks, leftward prism adaptation selectively increased verbal supraspan, i.e., increased the number of digits in the correct sequence reproduced and reduced the number of repetitions needed to learn the supraspan sequence. On the other hand, rightward prism adaptation selectively increased spatial supraspan, i.e. it increased the number of spatial positions in the correct sequence reproduced and reduced the number of repetitions needed to learn the supraspan sequence. Moreover, rightward, but not leftward, prism adaptation selectively increased supraspan recall after a delay interval, regardless of the stimulus material, i.e., it increased the number of digits or spatial positions recalled after a delay interval. Neutral lenses exposure did not influence any memory task. These findings suggest that prism adaptation can induce both modality/hemispheric-specific and process-specific effects on short-term and long-term explicit memory.

Effect of Fresnel prism in small-angle esotropia (≤ 20 prism diopters) with fixation preference.

We aimed to investigate the effects of Fresnel prism treatment for small-angle esotropia (≤ 20 prism diopters [PD]) with fixation preference. We included 32 patients with remaining esotropia ≤ 20 PD measured using the simultaneous prism and cover test (SPCT) after full refractive error correction. Fresnel prism was applied to make patients orthotropic with glasses. Treatment was discontinued if remaining esotropia ≤ 4 PD was sustained during two consecutive follow-ups (2-month intervals) or if the angle continued to increase with prism adaptation. Patients were divided into treatment success and failure groups. Treatment success was defined by motor and visual acuity (VA) aspects. Criteria for motor success was residual esotropia ≤ 8 PD in patients with initial esotropia > 8 PD and a 30% decrease of esotropia in those with initial esotropia ≤ 8 PD. VA success was improvement of > 0.2 logMAR in the non-dominant eye. The initial esodeviation angle was 6.92 ± 4.66 PD at distance and 10.53 ± 5.58 at near. The logMAR VA was 0.10 ± 0.13 and 0.26 ± 0.20 in the dominant and non-dominant eye, respectively. Among the 32 patients, 14 showed motor success. Among 26 patients whose VA could be measured, 15 showed VA success. Factors influencing motor success were a small amount of maximum prescribed Fresnel prism, less frequent need for Fresnel prism adaptation, and high percentage of achieving orthotropia with Fresnel prism treatment. VA success was influenced by low frequency of anisometropia and the small amount of maximum prescribed Fresnel prism. Fresnel prism could be a non-invasive treatment option for some patients with small-angle esotropia with fixation preference. What is known The optimal approach for addressing small-angle esotropia is a topic of debate. Not much research has been conducted on Fresnel prism treatment in patients with small-angle esotropia. What is new Motor success and visual acuity improvement were observed in some patients undergoing Fresnel prism treatment. Factors contributing to motor success were the small maximum angle of esodeviation, the less frequent necessity for Fresnel prism adaptation, and the achievement of orthotropia during Fresnel prism treatment. Visual acuity improvement was hindered by the presence of anisometropia and thelarge maximum prescribed amount of Fresnel prism. Fresnel prism treatment can be used as a treatment option for some patients with small-angle esotropia with fixation preference.

Neck muscle vibration and prism adaptation fail to improve balance disturbances after stroke: A multicentre randomised controlled study

BackgroundPilot studies suggest potential effects of neck muscle vibration (NMV) and prism adaptation (PA) on postural balance disturbances related to spatial cognition. ObjectivesTo evaluate the effect of 10 sessions of NMV and/or PA on ML deviation. We used the mediolateral centre of pressure position (ML deviation) as a biomarker for spatial cognition perturbation, hypothesising that PA and NMV would improve ML deviation, with a potential synergistic impact when used together. MethodsWe conducted a multicentre, single-blind, randomised controlled study. Participants within 9 months of a right-hemisphere supratentorial stroke and with less than 40% body weight supported on the paretic side in standing were randomised into 4 groups (PA, NMV, PA+NMV, or control). Primary outcomeML deviation at Day 14. Secondary outcomes: force platform data, balance abilities, autonomy, and ML deviation, measured just after the first session (Day 1), at Day 90, and Day 180. A generalised linear mixed model (GLMM) assessed intervention effects on these outcomes, adjusting for initial ML deviation and incorporating other relevant factors. Results89 participants were randomised and data from 80 participants, mean (SD) age 59.2 (10.2) years, mean time since stroke 94 (61) days were analysed. At Day 14, a weak time x group interaction (P = .001, omega-squared = 0.08) was found, with no significant between-group differences in ML deviation (P = .12) or in secondary outcomes (P = .08). Between-group differences were found on Day 1 (P = .03), Day 90 (P = .001) and Day 180 (P < .0001) regardless of age and stroke-related data. On Day 1, ML deviation improved in both the PA and NMV groups (P = .03 and P = .01). In contrast, ML deviation deteriorated in the NMV+PA group on Day 90 and Day 180 (P = .01 and P = .01). ConclusionsThe study found no evidence of any beneficial effects of repeated unimodal or combined sessions of NMV and/or PA on ML deviation after stroke. Trial registrationClinicalTrials.gov identifier NCT01677091

A Critical Comment on Recent Reviews of Prism Adaptation Training: It’s Too Early to Close the Shop

A Critical Comment on Recent Reviews of Prism Adaptation Training: It’s Too Early to Close the Shop

Comparative assessment of prism alternate cover test at near, distance, far distance before and after patching and prism adaptation test in concomitant horizontal strabismus

Comparative assessment of prism alternate cover test at near, distance, far distance before and after patching and prism adaptation test in concomitant horizontal strabismus

Auditory-motor adaptation: induction of a lateral shift in sound localization after biased immersive virtual reality training

IntroductionSensorimotor adaptation has often been studied in the visual modality through the Prism Adaptation (PA) paradigm. In this paradigm, a lateral shift in visual pointing was found after wearing prismatic goggles. An effect of PA has sometimes been observed on hearing, in favor of a cross-modality recalibration. However, no study has ever shown if a biased auditory-motor adaptation could induce this lateral shift, which appears essential to a better understanding of the mechanisms of auditory adaptation. The present study aimed at inducing an auditory prism-like effect.MethodsSixty healthy young adults underwent a session of active audio-proprioceptive training in immersive virtual reality based on Head Related Transfer Functions (HRTF). This training consisted of a game in which the hand-held controller emitted sounds either at its actual position in a control group or at 10° or 20° to the right of its actual position in two experimental groups. Sound localization was assessed before and after the training.ResultsThe difference between both localization tests was significantly different between the three groups. As expected, the difference was significantly leftward for the group with a 20° deviation compared to the control group. However, this effect is due to a significant rightward deviation in the control group whereas no significant difference between localization tests emerged in the two experimental groups, suggesting that other factors such as fatigue may have cumulated with the training after-effect.DiscussionMore studies are needed to determine which angle of deviation and which number of sessions of this audio-proprioceptive training are required to obtain the best after-effect. Although the coupling of hearing and vision in PA still needs to be studied, adding spatial hearing to PA programs could be a promising way to reinforce after-effects and optimize their benefits.

Vertical prism adaptation, but not sound presentation, modulates the visuospatial representation: A manual line-bisection study

The present study aimed at testing whether vertical prism adaptation (PA) can modulate vertical visuospatial representation, assessed with a vertical manual line-bisection (MLB) task (Experiment 1). In a second time, we wanted to investigate the potential influence of sound presentation during such a task. Sound is a spatially valued element that has previously been reported to modify horizontal visuospatial representation. In Experiment 2, we presented either a high pitch, a low pitch, or no sound during the same MLB as in Experiment 1. With this experiment, we also searched for an eventual interaction between the effect of sound presentation and the potential cognitive aftereffects of vertical PA on visual representation.Both Experiments 1 and 2 were constructed with the same design and conducted with two distinct groups of young healthy right-handed participants. First, we assessed the initial sensorimotor state with an open-loop pointing task, and the initial representational state through a vertical MLB (with addition of sound for Experiment 2). Then participants were submitted to a 16-minute PA procedure and were tested again on the open-loop pointing task and the MLB to assess the aftereffects following prism removal.Our results showed sensorimotor aftereffects following both upward and downward PA, in a direction opposed to the optical deviation used. The early aftereffects measured following PA were symmetrical, but at the end of the experiment the residual aftereffects were smaller following downward PA than upward PA. We also provide a new insight on the aftereffects of vertical PA on visuospatial representation, showing that downward PA (but not upward PA) can produce an upward bias on the manual line-bisection task. This is the first proof of such cognitive aftereffects following vertical PA. However, we found no effect of sound presentation on the vertical visual space representation and no interaction between PA and sound presentation.

Region-specific Effects of Transcranial Direct Current Stimulation Over Posterior Parietal Cortex and Cerebellum on Standing Postural Displacement After Prism Adaptation

Prism adaptation (PA) induces the after-effects of adapted tasks and transfers after-effects of non-adapted tasks, in which PA with pointing movements transfers to postural displacement during eyes-closed standing. However, the neural mechanisms underlying the transfer of PA after-effects on standing postural displacement remain unclear. The present study investigated the region-specific effects of transcranial direct current stimulation (tDCS) over the posterior parietal cortex (PPC) and cerebellum during prism exposure (PE) on standing postural displacement in healthy adults. Forty-two healthy young adults were grouped into pointing during PE with cathodal tDCS over the right PPC, anodal tDCS over the right cerebellum, and sham tDCS groups. They received 20 min of tDCS, during which they pointed to the visual targets while wearing prism lenses with a leftward visual shift (30 diopters) for 15 min. During the early PE, the pointing errors in the cerebellum group were significantly displaced more accurately toward the targets than those in the PPC group. However, after leftward PE, all groups had similar rightward displacements of the straight-ahead pointing with eyes closed. The PPC group only exhibited significant rightward center-of-pressure displacement during eyes-closed standing with feet-closed after leftward PE. The perception of longitudinal body axis rotation, as an indicator of the subjective body vertical axis, did not differ significantly between the pre- and post-evaluations in all groups. These results show that the PPC during PE could make an important neural contribution to inducing transfer of PA after-effect on standing postural displacement.

Rehabilitation for Unilateral Spatial Neglect

Unilateral spatial neglect (USN) is a symptom of unilateral brain damage resulting in failure to report sensory phenomena in the contra-lesional space. It is associated with motor impairment as well as sensory deficits. Recent research suggests that USN, may be caused by a disruption in the interhemispheric balance of the visual attention network. Based on this hypothesis, non-invasive brain stimulation (NIBS), such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), is utilized in the rehabilitation of USN patients. Presently, inhibitory stimulation by continuous theta burst stimulation (cTBS) on contra-lesional parietal cortex are believed to be the most promising method. Conversely, compensation by attentional network of the non-lesioned hemisphere plays an important role in the recovery of USN. Recent imaging studies revealed that functional and structural connectivity of attentional networks within a lesioned hemisphere and between lesioned and non-lesioned hemispheres affects spontaneous recovery and effectiveness of rehabilitation approach such as prism adaptation therapy. These findings are useful in elucidating the pathophysiology of USN and predicting functional outcome. Furthermore, we hope that understanding the pathophysiology will enable the development of new rehabilitation strategies and appropriate treatment selection.

Effect of 4-week preoperative prism adaptation in preventing postoperative residual esotropia.

Preoperative prism adaptation (PPA) simulates postoperative status and possibly can predict postoperative undercorrection before surgery in esotropia. The present study aimed to assess the effect of 4-week PPA in preventing postoperative residual esotropia. Seventy-five (75) esotropes who had undergone surgery at a single strabismus center were retrospectively enrolled. They included 25 basic, 31 acute comitant, 10 partially accommodative, and 9 recurrent esotropia patients. The preoperative deviation angle, which had been determined using the alternating prism and cover test, was fully corrected with press-on prisms 4 weeks before surgery. If there was an increase of 5 PD or more of esodeviation, the prisms were changed accordingly at 2 weeks. The deviation angle measured at 4 weeks was determined as the surgical target angle. Patients were then divided into increase (≥ 5 PD increase of angle during 4-week PPA) and non-increase groups. Success was defined as either esodeviation of 8 PD or under or exodeviation of 5 PD or under at distance at postoperative 6 months. The increase group included 44 patients (58.7%). The mean deviation angle before PPA was 27.4 PD, and after the 4-week PPA, there was an average increase of 9.4 PD. The success rate was 90.9% in the increase group and 96.8% in the non-increase group (p = 0.316). There were no intergroup differences in preoperative clinical characteristics, esotropia types, postoperative deviation angle or postoperative near stereopsis (p > 0.05). The results of this study indicated a beneficial effect of 4-week PPA in esotropia of various types, specifically by uncovering the hidden esodeviation in the increase group and simulating the postoperative alignment in both the increase and the non-increase groups.

Influence of postural control difficulty on changes in spatial orienting of attention after leftward prism adaptation.

Prism adaptation (PA) affects visuospatial attention such as spatial orienting in both the right and left hemifields; however, the systematic after-effects of PA on visuospatial attention remain unclear. Visuospatial attention can be affected by non-spatial attentional factors, and postural control difficulty, which delays the reaction time (RT) to external stimulation, may be one such factor. Therefore, we aimed to investigate the influence of postural control difficulty on changes in spatial orienting of attention after leftward PA. Seventeen healthy young adults underwent 15-min and 5-min PA procedures for a leftward visual shift (30 diopters). Participants underwent the Posner cueing test immediately before (pre-evaluation) and in between and after the PA procedures (post-evaluations) while standing barefoot on the floor (normal standing condition) and on a balance-disc (balance standing condition). In the pre-evaluation, RTs in the balance standing condition were significantly longer compared to those in the normal standing condition for targets appearing in both the right and left hemifields. Leftward PA improved the RT for targets appearing in the right, but no left, hemifield in the balance standing condition, such that RTs for targets in the right hemifield in the post-evaluation were not significantly different between the two standing conditions. However, leftward PA did not significantly change RTs for targets in both hemifields in the normal standing condition. Therefore, postural control difficulty may enhance sensitivity to the features of the visuospatial cognitive after-effects of leftward PA.

Acute effects of prismatic adaptation on penalty kick accuracy and postural control in young soccer players: A pilot study

BackgroundPrismatic adaptation (PA) is a visuomotor technique using prismatic glasses that are capable of moving the visual field and to affect the excitability of certain brain areas. The aim of this pilot study was to explore potential acute effects of PA on penalty kick accuracy and postural control in youth soccer players. MethodsIn this randomized crossover study, seven young male soccer players performed three PA sessions (rightward PA, r-PA; leftward PA, l-PA; sham PA, s-PA) with a washout period of 1-week between them. Immediately before and after each PA session, penalty kick accuracy and postural control were assessed. ResultsWe detected an increase in penalty kick accuracy following PA, regardless of the deviation side of the prismatic glasses (F1,5 = 52.15; p = 0.08; ηp2 = 0.981). In detail, our results showed an increase in the penalty kick accuracy toward the right target of the football goal following r-PA and toward the left target of the football goal following l-PA. We detected a significant effect on the sway path length (F2,12 = 10.42; p = 0.002; ηp2 = 0.635) and the sway average speed (F2,12 = 9.17; p = 0.004; ηp2 = 0.605) parameters in the stabilometric test with open eyes following PA, regardless of the deviation side of the prismatic glasses. In detail, our results showed a significant difference in both the stabilometric parameters (p = 0.016 and p = 0.009, respectively) only following l-PA. ConclusionThe findings of this pilot study indicate that PA could positively affect penalty kick accuracy and postural control suggesting that PA could be used as a visual training technique in athletes.

Prismatic adaptation coupled with cognitive training as novel treatment for developmental dyslexia: a randomized controlled trial

Despite intense and costly treatments, developmental dyslexia (DD) often persists into adulthood. Several brain skills unrelated to speech sound processing (i.e., phonology), including the spatial distribution of visual attention, are abnormal in DD and may represent possible treatment targets. This study explores the efficacy in DD of rightward prismatic adaptation (rPA), a visuomotor adaptation technique that enables visuo-attentive recalibration through shifts in the visual field induced by prismatic goggles. A digital intervention of rPA plus cognitive training was delivered weekly over 10 weeks to adolescents with DD (aged 13–17) assigned either to treatment (N = 35) or waitlist (N = 35) group. Efficacy was evaluated by repeated measures MANOVA assessing changes in working memory index (WMI), processing speed index (PSI), text reading speed, and words/pseudowords reading accuracy. rPA treatment was significantly more effective than waitlist (p ≤ 0.001; ηp2 = 0.815). WMI, PSI, and reading speed increased in the intervention group only (p ≤ 0.001, ηp2 = 0.67; p ≤ 0.001, ηp2 = 0.58; p ≤ 0.001, ηp2 = 0.29, respectively). Although modest change was detected for words and pseudowords accuracy in the waitlist group only (words: p ≤ 0.001, d = 0.17, pseudowords: p = 0.028; d = 0.27), between-group differences were non-significant. rPA-coupled cognitive training enhances cognitive and reading abilities in adolescents with DD. This innovative approach could have implications for early remedial treatment.

Development of a virtual reality system that generates prism adaptation for multiple motor units

AbstractConventionally, the adaptive body area for prism adaptation (PA) has been limited to the visible area of prism glasses, especially the unilateral upper limbs. In this study, we developed a virtual reality system that extends PA's adaptive body area. This system sets the visible area of the target and introduces a symbolic representation of the body position to realize a head position adaptation task. As a result, the develped system generates PA not to individual body parts but to a collection of multiple motor units. Furthermore, experimental results in healthy subjects showed that the head position adaptation task could generate PA in the upper trunk system (The upper trunk system is defined as a system consisting of the upper trunk, head, and upper extremities) and displace it to the left anteriorly. Therefore, the head position adaptation task is expected to be effective for the postural correction of USN patients with upper trunk system tilt to the right posteriorly. Moreover, the developed system has potential applications in a wide range of fields, such as detecting cerebellar disorders.

Is recalibration more important than realignment in prism adaptation training for visuospatial neglect? A randomized controlled trial

ABSTRACT Prism adaptation training (PAT) as a treatment for visuospatial neglect (VSN) involves two components: recalibration and realignment. We conducted a randomized controlled trial with PAT protocols requiring different degrees of recalibration and realignment, by using a single or multi-step protocol and varying visibility of the pointing movement. Twenty-five VSN patients received an alertness treatment without prisms, followed by four PAT protocols, encompassing a multi- or single-step procedure with terminal exposure, a single-step procedure with concurrent exposure, and sham PAT, presented in random order. The primary outcome parameter was the mean response time (RT) to left-sided targets in an endogenous variant of the Posner task, and we also measured the sensorimotor aftereffect. The two protocols without visibility of most of the movement trajectory produced significant aftereffects. The single-step protocol without movement visibility resulted in shorter RTs to left-sided targets. Hence, aftereffects depended on the partial invisibility of the movement. Moreover, only allowing VSN patients to recalibrate several times and direct feedback from the pointing errors had a beneficial effect on non-motor leftward visuospatial attention. We provide preliminary evidence that maximizing the conscious experience of movement errors may be an important component for remediating VSN. Trial registration: German Clinical Trials Register identifier: DRKS00025938.

Wykorzystanie testu adaptacji pryzmatycznej oraz jednoocznej okluzji w przygotowaniu przedoperacyjnym pacjenta z zezem

In patients with strabismus the prism adaptation test and monocular occlusion allow revealing the maximum angle of deviation before strabismus surgery. Furthermore, these procedures are helpful in differentiating the types of strabismus.

Post-stroke rehabilitation in the peri-pandemic COVID-19 era.

The coronavirus disease 2019 (COVID-19), which arosein late 2019, caused extensive destruction, impacting a substantial proportion of the worldwide population and leading to millions of deaths. Although COVID-19 is mainly linked to respiratory and pulmonary complications, it has the potential to affect neurologic structures as well. Neurological involvement may manifest as minimal and reversible; however, a notable proportion of cases have exhibited pronounced neurological consequences, such as strokes. Endothelial inflammation, hypercoagulation, renin-angiotensin-aldosterone system alterations, and cardiogenic embolism are the pathophysiological mechanismsof stroke under COVID-19 circumstances. Physical activity and exercise have improved several aspects of post-stroke recovery, including cardiovascular health, walking capacity, and upper limb strength. They are commonly used to assist stroke survivors in overcomingtheir motor restrictions. Furthermore, stroke rehabilitation can incorporate a range of specific techniques, including body-weight-supported treadmill applications, constraint-induced movement therapy, robotic rehabilitation interventions, transcranial direct current stimulation, transcranial magnetic stimulation, and prism adaptation training. Under pandemic conditions, there were several barriers to neurological rehabilitation. The most significant of these were individual's fear of infection, which caused them to postpone their rehabilitation applicationsand rehabilitation areas being converted into COVID-19 units. The primary emphasis had turned to COVID-19 treatment. Several valuable data and views were gained in reorganizing rehabilitation during the pandemic, contributing to establishing future views in this regard.

From real to virtual prism adaptation therapy: a systematic review on benefits and challenges of a new potential rehabilitation approach.

Prism adaptation (PA) is a sensorimotor technique that has been shown to alleviate neglect symptoms. Due to its demonstrated functional effectiveness, PA has recently been implemented in virtual reality environments. However, research on virtual prism adaptation (VPA) is limited and it lacks a standardized methodological approach. It is crucial to investigate whether VPA can be effective in inducing traditional effect of PA and to have potential utility in a rehabilitation context. Clarifying this aspect would allow the use of VPA in a wider range of contexts and neurological disorders, with the additional opportunity to overcome PA traditional limits. The aim of the present study is to revise current literature on VPA in both healthy individuals and patients highlighting also its advantages and limitations. Studies performed between 2013 and 2023 and fulfilling the inclusion criteria were searched on three electronic databases, by combining the terms "Virtual prism adaptation" and "Virtual prism adaptation therapy. Out of 123 articles, only 16 met the inclusion criteria. The current literature review suggests that VPA may serve as a potentially useful tool for inducing visuomotor adaptation, with most studies conducted in healthy individuals. The high variability in the methodologies observed among studies suggests that more standardized approaches are needed to gain a deeper understanding of the mechanisms underlying adaptation and aftereffects when PA is administered in a virtual environment. Future studies should also address practical applications and clinical efficacy of VPA, particularly in patients with spatial neglect.

The ability to maintain rhythm is predictive of ADHD diagnosis and profile

Attention deficit hyperactivity disorder (ADHD) is the most prevalent neuropsychiatric disorder in the world. Currently, the diagnosis is based mainly on interviews, resulting in uncertainties in the clinical assessment. While some neuropsychological tests are used, their specificity and selectivity are low, and more reliable biomarkers are desirable. Previous research indicates that ADHD is associated with morphological changes in the cerebellum, which is essential for motor ability and timing. Here, we compared 29 children diagnosed with ADHD to 96 age-matched controls on prism adaptation, eyeblink conditioning, and timed motor performance in a finger tapping task. Prism adaptation and timing precision in the finger tapping task, but not performance on eyeblink conditioning, differed between the ADHD and control groups, as well as between children with and without Deficits in Attention, Motor control, and Perception (DAMP) – a more severe form of ADHD. The results suggest finger tapping can be used as a cheap, objective, and unbiased biomarker to complement current diagnostic procedures.

Prism adaptation treatment improves spatial neglect after severe traumatic brain injury: A case series.

Spatial neglect (SN) after traumatic brain injury (TBI) is common, hindering rehabilitation progress and functional outcomes. Most research has focused on SN treatment after stroke with few published instances of post-TBI SN treated using prism adaptation treatment (PAT) in inpatient rehabilitation. This case series characterizes the dose, after-effect, and treatment response of PAT in patients with SN after severe TBI. Six patients exhibiting severe (n = 2), moderate (n = 2), or mild (n = 2) SN after severe TBI received 5 to 10 PAT sessions during their inpatient rehabilitation stay. Functional improvement in SN was measured by the Catherine Bergego Scale (CBS). Patients presented with a mean initial CBS score of 16.8 (range: 8.8-24.3). Prism after-effect was present after PAT. Following 5-10 sessions, the mean CBS score improved by 11.6 points to 5.2 (range: 7.8-21.8); the change in initial versus final CBS scores was significant (P = 0.031). This study is the first to demonstrate prism after-effect and functional SN improvement in individual patients with TBI. Patients showed a clinically meaningful improvement in mild, moderate, and severe SN following 5 to 10 PAT sessions. Additional studies are needed to assess tolerability, benefit, and optimal PAT dose for SN after TBI.