Motor Imagery-Based Brain-Computer Interface Combined with Multimodal Feedback to Promote Upper Limb Motor Function after Stroke: A Preliminary Study.

BACKGROUND: Recently, the brain-computer interface (BCI) has seen rapid development, which may promote the recovery of motor function in chronic stroke patients. METHODS: Twelve stroke patients with severe upper limb and hand motor impairment were enrolled and randomly assigned into two groups: motor imagery (MI)-based BCI training with multimodal feedback (BCI group, n = 7) and classical motor imagery training (control group, n = 5). Motor function and electrophysiology were evaluated before and after the intervention. The Fugl-Meyer assessment-upper extremity (FMA-UE) is the primary outcome measure. Secondary outcome measures include an increase in wrist active extension or surface electromyography (the amplitude and cocontraction of extensor carpi radialis during movement), the action research arm test (ARAT), the motor status scale (MSS), and Barthel index (BI). Time-frequency analysis and power spectral analysis were used to reflect the electroencephalogram (EEG) change before and after the intervention. RESULTS: Compared with the baseline, the FMA-UE score increased significantly in the BCI group (p = 0.006). MSS scores improved significantly in both groups, while ARAT did not improve significantly. In addition, before the intervention, all patients could not actively extend their wrists or just had muscle contractions. After the intervention, four patients regained the ability to extend their paretic wrists (two in each group). The amplitude and area under the curve of extensor carpi radialis improved to some extent, but there was no statistical significance between the groups. CONCLUSION: MI-based BCI combined with sensory and visual feedback might improve severe upper limb and hand impairment in chronic stroke patients, showing the potential for application in rehabilitation medicine.

Topical anesthesia versus regional anesthesia for cataract surgery: a meta-analysis of randomized controlled trials.

PURPOSE: To examine possible differences in the clinical outcomes of topical anesthesia (TA) and regional anesthesia including retrobulbar anesthesia (RBA) and peribulbar anesthesia (PBA) in phacoemulsification. DESIGN: Systematic review and meta-analysis. PARTICIPANTS: Patients from previously published randomized controlled trials (RCTs) of phacoemulsification under TA and RBA/PBA reporting clinical outcomes. METHODS: A comprehensive literature search was performed according to the Cochrane Collaboration method to identify RCTs that compare TA and RBA/PBA in phacoemulsification. MAIN OUTCOME MEASURES: Primary outcome parameters investigated were pain score during and after surgery, intraoperative difficulties and inadvertent ocular movement, intraoperative necessity to administer additional anesthesia, and patient preference. Secondary outcome parameters investigated were postoperative visual acuity, anesthesia-related complications, intraoperative complications, and severe local or systemic complications. RESULTS: Fifteen studies were identified and analyzed to compare TA (1084 eyes) with RBA/PBA (1121 eyes) in phacoemulsification. Data synthesis showed that intraoperative and postoperative pain perception was significantly higher in the TA group (P < 0.05). The TA group showed more frequent inadvertent ocular movement (P < 0.05) and a greater intraoperative need for supplementary anesthesia (P = 0.03). There was no statistically significant difference between the 2 groups in intraoperative difficulties as assessed by the surgeons (P > 0.05). Patients significantly preferred TA (P < 0.00001). The RBA/PBA group had more frequent anesthesia-related complications, such as chemosis, periorbital hematoma, and subconjunctival hemorrhage (P < 0.05). There was no statistically significant difference in surgery-related complications (P > 0.05). CONCLUSIONS: Compared with RBA/PBA, TA does not provide the same excellent pain relief in cataract surgery; however, it achieves similar surgical outcomes. Topical anesthesia reduces injection-related complications and alleviates patients' fear of injection. The choice of TA is not suitable for patients with a higher initial blood pressure or greater pain perception.

A systematic review and meta-analysis of clinical outcomes of vitrectomy with or without intravitreal bevacizumab pretreatment for severe diabetic retinopathy.

AIMS: To examine possible benefits of intravitreal bevacizumab (IVB) pretreatment in vitrectomy for severe diabetic retinopathy. METHODS: A comprehensive literature search was performed using the Cochrane Collaboration methodology to identify randomised controlled trials and comparative studies of vitrectomy with or without IVB pretreatment for severe or complicated diabetic retinopathy. Meta-analyses were performed for intraoperative (including intraoperative bleeding, endodiathermy, iatrogenic retinal tears and mean surgical time) and postoperative outcome parameters (including best-corrected visual acuity, recurrent vitreous haemorrhage, reabsorption time of blood and other complications). RESULTS: Six randomised controlled trials and one comparative study were identified and used for comparing vitrectomy alone (142 eyes, control group) with vitrectomy with IVB pretreatment (139 eyes). The intraoperative findings showed that the incidence of intraoperative bleeding and frequency of endodiathermy were statistically significantly less in the IVB pretreatment group (p<0.01) than in the vitrectomy alone group. The IVB pretreatment group took significantly less surgical time than the control group (p=0.003). Postoperative results indicated that reabsorption time of blood was significantly shorter (p=0.04), incidence of recurrent VH was almost significantly less (p=0.05), and final best-corrected visual acuity was significantly better (p=0.003) in the IVB group than in the control group. Other complications, including final retinal detachment, and reoperation, were statistically insignificant. CONCLUSION: IVB pretreatment in vitrectomy can achieve excellent clinical outcomes for severe diabetic retinopathy. It potentially facilitates surgeons' manoeuvres and reduces intra- and postoperative complications.

Practical method to calculate post-LASIK corneal power: the Actual K(a+p) method.

AIM: To evaluate the accuracy of a practical method (the Actual K(a+p) method) of corneal power measurement for post-LASIK eyes undergoing cataract surgery. METHODS: Ten eyes of 7 patients (4 male, 3 female, average age 50.10±4.01 years, with -11.01±3.55D mean refraction before LASIK), underwent post-LASIK phaco+IOL cataract surgery. We used the posterior corneal curvature as measured by the Pentacam in a method we named Actual K(a+p) to calculate the post-LASIK corneal power for IOL calculation. The refractive outcomes after cataract surgery were evaluated. The Actual K(a+p) was compared with the back- calculated corneal power (BCK), which was thought to be the benchmark of true corneal power. The corneal power estimated by other published methods, including Maloney, Shammas, Koch-Maloney, Savini, and McCulley, together with the true net power and equivalent K reading (EKR) as found by the Pentacam were also compared with the BCK. RESULTS: All eyes achieved satisfied refractive status after cataract surgery. The difference between the postoperative refraction and the target refraction was 0.04±0.40D, range from -0.63D and +0.85D. Among all the methods we studied, although the Bonferroni multiple comparison tests did not detect significant differences between any two of them, the Actual K(a+p) yielded the highest agreement with the BCK, with 80% of the eyes falling within ±0.5D and 100% within ±1.0D from the BCK values. CONCLUSION: The Actual K(a+p) method can provide encour- aging results in post-LASIK eyes undergoing cataract surgery.

[The accuracy of posterior curvature method in corneal power calculation after LASIK surgery].

OBJECTIVE: To estimate the accuracy of posterior curvature method in corneal power calculation after LASIK surgery. METHODS: Corneal power calculation in 11 eyes that underwent Intraocular Lens (IOL) implantation after LASIK surgery (10 cases of Phaco + IOL, 1 case of IOL displacement), all of which used posterior curvature method, was analyzed retrospectively. The differences between post-operative stable refraction and target refraction were calculated, the actual corneal powers were deduced, and the expected refractive errors using other corneal power evaluation methods (auto-keratometry, corneal topography, spherical equivalent method, anterior curvature method, Equivalent K Reading method provided by Pentacam) were analyzed. In addition, refraction of 23 eyes underwent LASIK surgery were done on their 6 months follow-up. The theoretical corneal powers were deduced by subtracting the change of refraction before and after LASIK surgery from the pre-operative corneal powers. The differences between calculated corneal powers using posterior curvature method and the theoretical corneal powers were analyzed, and were compared with other corneal power evaluation methods. RESULTS: The mean uncorrected post-operative visual acuity of IOL implantation eyes using posterior curvature method was 0.8 +/- 0.2, with mean absolute refractive error from target of (0.36 +/- 0.36) D (-0.63 to +0.85 D). The ratio of eyes with absolute error within 0.25 D, 0.50 D, and 1.00 D was 55%, 73%, and 91% respectively. This result was significantly lower than that of the auto-keratometry (2.50 +/- 1.08) D, corneal topography (1.90 +/- 0.88) D, and those obtained from spherical equivalent method (2.09 +/- 1.62) D (P < 0.01) or anterior curvature method (1.45 +/- 1.10) D (P < 0.05). It also showed less bias (-1.13 to 0.85 D) when compared to the Equivalent K Reading (-1.10 to 1.80 D), but the difference was not significant (P > 0.05). For the 23 post LASIK eyes, the absolute difference between the corrected corneal power using posterior curvature method and theoretical power was (0.67 +/- 0.45) D, also showed least bias compared with other methods. CONCLUSION: It is a practical and accurate way to calculate the corneal power after LASIK surgery using posterior curvature method.