Clinical and demographic predictors of unilateral spatial neglect recovery after prism therapy among stroke survivors in the sub-acute phase of recovery.

BACKGROUND AND AIMS: Unilateral Spatial Neglect (USN) affects the rehabilitation process and leads to poor outcomes after stroke. Factors that influence USN recovery following prism adaptation therapy have not been investigated. This study investigated predictors of USN recovery after prism therapy at the sub-acute phase of recovery. METHODS: This study was a randomized controlled trial. USN was assessed with the Behavioural Inattention Test and Catherine Bergego scale. Seventy-four patients with USN were divided into control and intervention group (prism). The prism group used 20 dioptre prism lenses for repeated aiming for 12 sessions while the control group used neutral lenses for aiming training. Regression analysis was conducted to establish clinical and sociodemographic factors that influence USN recovery. RESULTS: Gender, age, years of education, race, employment status, handedness, type of stroke, time since stroke and site of stroke (p > 0.005) showed no significant influence on USN recovery following PA treatment. Higher Cognitive function (OR = 1.52, CI = 1.08-2.14, p = 0.016) and group allocationng (being in the prism group) (OR = 63.10, CI = 9.70-410.59, P < 0.001) were found to significantly influence USN recovery following PA treatment session. CONCLUSIONS: A significant modulating effect on general cognitive ability was found in this study. This suggests that prism adaptation therapy's effect on neural activity and spatial neglect depends on the cognitive function of stroke survivors.Trial registration: Pan African Clinical Trial Registry identifier: PACTR201903732473573.

Spectacle Decentration to Augment Over-minus Therapy in Cases with Intermittent Exotropia.

Purpose: To evaluate the adding effect of inward decentration of concave spectacle lenses (adding a prismatic effect) on angle control in cases with distance intermittent exotropia (IXT) receiving over-minus therapy.Methods: Patients with myopia with IXT angles ≤25 and a Newcastle score (NCS) ≥5 were included. Patients were randomised into two groups. Group 1 received over-minus therapy. Group 2 received over-minus therapy with inward decentration of spectacle glasses to add a base out prism effect equal to one-third of the distance angle of deviation. Success was measured as the percentage of orthotropic cases or those with orthophoria or IXT with improved NCS ≤ 3 and tolerant to treatment. Patients were evaluated 3 months after initial treatment, 3 months after partial weaning and 18 months after complete weaning.Results: Sixty-four patients were included, with 32 in each group. The success rates of group 1 were 65.6%, 37.5%, and 31.3%, in group 2, the rates were 75%, 65.6%, and 65.6% for orthotropic cases or those with orthophoria or IXT with improved NCS ≤ 3, respectively. Moreover, NCS significantly improved in group 2 till last visit.Conclusion: Adding decentration to over-minus therapy can result in better control of small angle IXT and could be considered as a non-invasive and reversible therapy.

Is Inverse Prism Therapy Comparable to Conventional Prism Therapy for Improving Newcastle Scores in Patients with Basic Intermittent Exotropia?

Purpose: To determine the effect of prism orientation on the Newcastle Control Score (NCS) in patients with basic intermittent exotropia (IXT).Methods: Patients with IXT with a distant angle of deviation (DAD) ≤50∆ and NCS≥5 were recruited and randomly divided into two groups. The inverse prism (IP) group received a base-out Fresnel prism addition to achieving full refractive correction, and the conventional prism (CP) group received base-in Fresnel prism addition. The prism addition was equivalent to one-third of the mean DAD. Patients were evaluated 3 months after initial treatment, 3 months after partial weaning and 6 months after complete weaning. NCS and DAD values were compared. Tolerance was defined as the ability to wear the prescription 80% of waking hours.Results: Fifty patients were enrolled in each group. The IP group had 6 intolerant patients, and the CP group had 3 intolerant patients. NCS improved in both groups (from 6.2 ± 0.7 to 3.4 ± 2.5 in the IP group and from 6.4 ± 0.7 to 3.7 ± -2.2 in the CP group). However, the final NCS difference was nonsignificant (Mann-Whitney, p = .6). The DAD changes were not significantly different between the 2 groups (t-test = 0.04). The average DAD decreased from 31.9 ± 6.9∆ to 10.11 ± 11∆ in the IP group and from 30.7 ± 8.5∆ to 15.5 ± 13.5∆ in the CP group. Four patients in the CP group exhibited an increase in DAD.Conclusion: The two types of prism therapy showed comparable improvements in NCS.

A pilot randomized controlled trial comparing effectiveness of prism glasses, visual search training and standard care in hemianopia.

OBJECTIVE: Pilot trial to compare prism therapy and visual search training, for homonymous hemianopia, to standard care (information only). METHODS: Prospective, multicentre, parallel, single-blind, three-arm RCT across fifteen UK acute stroke units. PARTICIPANTS: Stroke survivors with homonymous hemianopia. INTERVENTIONS: Arm a (Fresnel prisms) for minimum 2 hours, 5 days per week over 6 weeks. Arm b (visual search training) for minimum 30 minutes, 5 days per week over 6 weeks. Arm c (standard care-information only). INCLUSION CRITERIA: Adult stroke survivors (>18 years), stable hemianopia, visual acuity better than 0.5 logMAR, refractive error within ±5 dioptres, ability to read/understand English and provide consent. OUTCOMES: Primary outcomes were change in visual field area from baseline to 26 weeks and calculation of sample size for a definitive trial. Secondary measures included Rivermead Mobility Index, Visual Function Questionnaire 25/10, Nottingham Extended Activities of Daily Living, Euro Qual, Short Form-12 questionnaires and Radner reading ability. Measures were post-randomization at baseline and 6, 12 and 26 weeks. RANDOMIZATION: Randomization block lists stratified by site and partial/complete hemianopia. BLINDING: Allocations disclosed to patients. Primary outcome assessor blind to treatment allocation. RESULTS: Eighty-seven patients were recruited: 27-Fresnel prisms, 30-visual search training and 30-standard care; 69% male; mean age 69 years (SD 12). At 26 weeks, full results for 24, 24 and 22 patients, respectively, were compared to baseline. Sample size calculation for a definitive trial determined as 269 participants per arm for a 200 degree2 visual field area change at 90% power. Non-significant relative change in area of visual field was 5%, 8% and 3.5%, respectively, for the three groups. Visual Function Questionnaire responses improved significantly from baseline to 26 weeks with visual search training (60 [SD 19] to 68.4 [SD 20]) compared to Fresnel prisms (68.5 [SD 16.4] to 68.2 [18.4]: 7% difference) and standard care (63.7 [SD 19.4] to 59.8 [SD 22.7]: 10% difference), P=.05. Related adverse events were common with Fresnel prisms (69.2%; typically headaches). CONCLUSIONS: No significant change occurred for area of visual field area across arms over follow-up. Visual search training had significant improvement in vision-related quality of life. Prism therapy produced adverse events in 69%. Visual search training results warrant further investigation.

Binocular rivalry with peripheral prisms used for hemianopia rehabilitation.

PURPOSE: To determine the relative binocular signal strength of moving images that are peripherally viewed through a monocular field expansion prism as opposed to moving images viewed directly. We hypothesised that prism blur might make prism images predominate less than images viewed directly with the other eye. METHODS: We employed the binocular rivalry paradigm to measure the relative binocular effectiveness of directly viewed vs prism images. Four normally-sighted subjects tracked the rivalrous visibility of opponent-coloured targets seen dichoptically in the same part of the retinal visual field, using monocular field expansion prisms to produce the dichoptic display. We analysed the effects of external signal strength (whether or not motion was present in either image), retinal position or eccentricity of the targets, and controlled for target saturation. RESULTS: We found that prism images predominate less than directly viewed images. When both eyes were presented with pattern in the dichoptic display, direct-to-prism predominance was 51%:31%. When only the direct view was presented with pattern, direct-to-prism predominance was 74%:12%; when only the prism view was presented with pattern, direct-to-prism predominance was 25%:58%. Dominance durations followed established binocular rivalry rules. CONCLUSIONS: The prism image in a monocular, peripheral field expansion prism is perceptually weaker than the corresponding direct image in the other eye. However, the prism image is still seen a significant proportion of the time, especially when no moving pattern is present in the direct view. We conclude that the rivalry ratio of the prism device is sufficiently effective for clinical applications.