Continuous ambulatory peritoneal dialysis catheter insertion by open technique: 20-year experience from a single center.

Introduction: Continuous ambulatory peritoneal dialysis (CAPD) catheter placement is a part of renal replacement therapy. We describe our 20-year experience in using the open technique and assess its safety, efficacy, and outcome in the treatment of end-stage renal disease patients. Methods: In a retrospective study, we analyzed data of all patients who had a CAPD catheter placed using our open dissection technique using local anesthesia over the previous 20 years, with minimum 1 year of follow-up. Intraoperative data, postoperative data, and complications were noted. Results: A total of 1410 cases were included in the study. The mean duration of follow-up was 72 ± 18 months (range 12-120 months). The mean operative time was 19 ± 7.5 min and mean hospital stay was 3 ± 1 days. No major intraoperative complications were noted. We observed a peritonitis rate of 0.49 episodes/patient/year. The most common reason for permanent catheter removal was refractory peritonitis in 21%, followed by flow failure in 7%, and ultrafiltration failure in 6.5%. The death-censored technical survival rate was 94.3%, 83.2%, 75.9%, 69.2%, and 60.6% patients at 1 year, 2 years, 3 years, 4 years, and 5 years, respectively. Conclusions: The open dissection method of peritoneal dialysis catheter insertion using local anesthesia at well-experienced center is a simple, painless, and uncomplicated procedure with excellent outcomes. Optimal exposure, judicious use of energy source, and using appropriate technique provide good technical success rate with lesser complications.

Robot-assisted laparoscopic ureteral reimplant: A single-center experience.

INTRODUCTION: Open ureteral reimplant has been the gold standard for management of lower ureteric strictures. With the widespread acceptance of robotic surgery, robotic-assisted laparoscopic ureteral reimplant (RALUR) is becoming the preferred choice for performing ureteral reimplant. We present our single-institution and single-surgeon experience of performing RALUR. MATERIALS AND METHODS: We performed a retrospective analysis of 40 patients who underwent RALUR at our institute in the last 5 years. Demographic data were recorded along with presenting complaint and diagnosis. Intraoperative variables included operative and docking time, blood loss, intraoperative complications, technique, and procedure performed. Postoperative data that were analyzed included complications, hospital stay, and outcomes. Patient satisfaction score was calculated using a numerical scale of points 1-6. RESULTS: The mean age of patients was 31.5 ± 9.8 years (r = 4-45). Male: female ratio was 3:5. The most common presenting symptom was flank pain, and the most common etiology was iatrogenic strictures in adults and congenital vesicoureteral reflux in children. The mean operative time and blood loss were 135.3 ± 45.1 min (r = 84-221) and 67.7 ± 31.4 ml (r = 32-118), respectively. There were no intraoperative complications and nil conversion to open surgery. The mean length of hospital stay was 4.5 ± 2.3 days (r = 3-9). Radiographic success was achieved in 41 out of 44 ureters. Eighty-five percent of the patients were completely satisfied with robotic approach and its outcomes. CONCLUSION: RALUR is a minimally invasive, safe, feasible, less morbid technique with good outcome.

Unilateral, 3D Arm Movement Kinematics Are Encoded in Ipsilateral Human Cortex.

There is increasing evidence that the hemisphere ipsilateral to a moving limb plays a role in planning and executing movements. However, the exact relationship between cortical activity and ipsilateral limb movements is uncertain. We sought to determine whether 3D arm movement kinematics (speed, velocity, and position) could be decoded from cortical signals recorded from the hemisphere ipsilateral to the moving limb. By having invasively monitored patients perform unilateral reaches with each arm, we also compared the encoding of contralateral and ipsilateral limb kinematics from a single cortical hemisphere. In four motor-intact human patients (three male, one female) implanted with electrocorticography electrodes for localization of their epileptic foci, we decoded 3D movement kinematics of both arms with accuracies above chance. Surprisingly, the spatial and spectral encoding of contralateral and ipsilateral limb kinematics was similar, enabling cross-prediction of kinematics between arms. These results clarify our understanding that the ipsilateral hemisphere robustly contributes to motor execution and supports that the information of complex movements is more bihemispherically represented in humans than has been previously understood.SIGNIFICANCE STATEMENT Although limb movements are traditionally understood to be driven by the cortical hemisphere contralateral to a moving limb, movement-related neural activity has also been found in the ipsilateral hemisphere. This study provides the first demonstration that 3D arm movement kinematics can be decoded from human electrocorticographic signals ipsilateral to the moving limb. Surprisingly, the spatial and spectral encoding of contralateral and ipsilateral limb kinematics was similar. The finding that specific kinematics are encoded in the ipsilateral hemisphere demonstrates that the ipsilateral hemisphere contributes to the execution of unilateral limb movements, improving our understanding of motor control. Additionally, the bihemisheric representation of voluntary movements has implications for the development of neuroprosthetic systems for reaching and for neurorehabilitation strategies following cortical injuries.

Human cortical-hippocampal dialogue in wake and slow-wave sleep.

Declarative memory consolidation is hypothesized to require a two-stage, reciprocal cortical-hippocampal dialogue. According to this model, higher frequency signals convey information from the cortex to hippocampus during wakefulness, but in the reverse direction during slow-wave sleep (SWS). Conversely, lower-frequency activity propagates from the information "receiver" to the "sender" to coordinate the timing of information transfer. Reversal of sender/receiver roles across wake and SWS implies that higher- and lower-frequency signaling should reverse direction between the cortex and hippocampus. However, direct evidence of such a reversal has been lacking in humans. Here, we use human resting-state fMRI and electrocorticography to demonstrate that δ-band activity and infraslow activity propagate in opposite directions between the hippocampus and cerebral cortex. Moreover, both δ activity and infraslow activity reverse propagation directions between the hippocampus and cerebral cortex across wake and SWS. These findings provide direct evidence for state-dependent reversals in human cortical-hippocampal communication.

Native ureteroureterostomy in renal allograft recipient surgery: A single-center 5-year experience.

INTRODUCTION: In renal transplant, surgeons use a myriad of ureteral anastomotic techniques. Although ureteroneocystostomy (UNC) using Lich-Gregoir extravesical anastomosis is used most commonly, ureteroureterostomy with native ureter has its own importance in certain situations. MATERIALS AND METHODS: We retrospectively reviewed records of patients who underwent renal transplantation at our center from March 2011 to February 2016. Records of patients who underwent ureteroureterostomy with the native ureter were reviewed for the indications and complications of the procedure. RESULTS: Of 1050 renal transplants during the study period, 32 patients underwent native ureteroureterostomy. Among these 32 patients, 20 patients were planned preoperatively for native ureteroureterostomy (elective), and intraoperative decision was made in 12 patients (emergency). On follow-up, only one patient had ureteral obstruction due to kink just distal to ureteroureterostomy and was managed by double-J stenting. Other patients had an expected postoperative course. CONCLUSION: In our experience, ureteroureterostomy with native ureter is technically and functionally good option for ureteric reimplantation in kidney transplant patients. It can be used selectively for elective and emergency situations where UNC is not possible. Hence, the kidney transplant surgeon should be well versed with both techniques.

Frequency-specific electrophysiologic correlates of resting state fMRI networks.

Resting state functional MRI (R-fMRI) studies have shown that slow (<0.1Hz), intrinsic fluctuations of the blood oxygen level dependent (BOLD) signal are temporally correlated within hierarchically organized functional systems known as resting state networks (RSNs) (Doucet et al., 2011). Most broadly, this hierarchy exhibits a dichotomy between two opposed systems (Fox et al., 2005). One system engages with the environment and includes the visual, auditory, and sensorimotor (SMN) networks as well as the dorsal attention network (DAN), which controls spatial attention. The other system includes the default mode network (DMN) and the fronto-parietal control system (FPC), RSNs that instantiate episodic memory and executive control, respectively. Here, we test the hypothesis, based on the spectral specificity of electrophysiologic responses to perceptual vs. memory tasks (Klimesch, 1999; Pfurtscheller and Lopes da Silva, 1999), that these two large-scale neural systems also manifest frequency specificity in the resting state. We measured the spatial correspondence between electrocorticographic (ECoG) band-limited power (BLP) and R-fMRI correlation patterns in awake, resting, human subjects. Our results show that, while gamma BLP correspondence was common throughout the brain, theta (4-8Hz) BLP correspondence was stronger in the DMN and FPC, whereas alpha (8-12Hz) correspondence was stronger in the SMN and DAN. Thus, the human brain, at rest, exhibits frequency specific electrophysiology, respecting both the spectral structure of task responses and the hierarchical organization of RSNs.

Robotic assisted laparoscopic adrenalectomy: Initial experience from a tertiary care centre in India.

INTRODUCTION: Laparoscopic adrenalectomy (LA) is now considered the standard for treatment of surgically correctable adrenal disorders. Robotic adrenalectomy has been performed worldwide and has established itself as safe, feasible and effective approach. We hereby present the first study in robotic transperitoneal LA from Indian subcontinent. MATERIALS AND METHODS: We conducted a retrospective evaluation of 25 patients who had undergone robotic assisted LA at a tertiary health centre by a single surgeon. Demographic, clinical, histopathological and perioperative outcome data were collected and analysed. RESULTS: Mean age of the patients was 45 years (range: 27-65 years). Eleven male and 14 female patients were operated. Mean operative time was 139 min ± 30 min (range: 110-232 min) and mean blood loss was 85 ml ± 12 ml (range: 34-313 ml). Mean hospital stay was 2.5 ± 1.05 days (range: 2-6 days). Mean visual analogue scale score was 3.2 (range: 1-6) mean analgesic requirement was 50 mg diclofenac daily (range: 0-150 mg). Histopathological evaluation revealed 11 adenomas, eight phaeochromocytomas, two adrenocortical carcinomas, and four myelolipomas. According to Clavien-Dindo classification, three patients developed Grade I post-operative complications namely hypotension and pleural effusion. CONCLUSION: Robotic adrenalectomy is safe, technically feasible and comfortable to the surgeon. It is easier to perform with a short learning curve.

Live donor kidney transplantation in India: effects of donor and recipient age on graft survival.

INTRODUCTION: The increasing gap between demand and supply of human kidneys has resulted in the use of more expanded criteria donor organs are used. The influence of age on short- and long-term survival of renal allograft has not been well studied in Indian population. MATERIALS AND METHODS: Two hundred and seventy-eight patients were evaluated retrospectively who underwent kidney transplantation from Jan 2008 to June 2011. Patients were divided into 6 groups: group A (donor age 20-40 years, recipient age <50 years), group B (donor age 20-40 years, recipient age >50 years), group C (donor age 40-60 years, recipient age <50 years), group D (donor age 40-60 years, recipient age >50 years), group E (donor age >60 years, recipient age <50 years) and group F (donor age >60 years, recipient age >50 years). Uni-variate analysis was used to assess the effect of donor and recipient age as predictive factors for graft outcome, using the Kaplan-Meier method (log-rank) with p < 0.05 considered significant. RESULTS: Graft survival was found to be lowest in elderly recipients and in patients with donor age >60 years. Renal function was superior using younger donors both in short and long term. The incidence of acute rejection was found to be lower in elderly donor group than in younger, although the difference was not statistically significant. CONCLUSION: Donor's higher age did not show significant impact on allograft survival although, kidney allografts demonstrated decreased short and long term renal function.

Evaluation of Biochemical Recurrence and Correlation with Various Parameters After Robotic-Assisted Radical Prostatectomy: a Single Center Experience.

Introduction: Biochemical recurrence (BCR) is widely used as an early end point to assess treatment success and frequently prompts the initiation of secondary therapy after radical prostatectomy. We conducted an observational, ambispective study to evaluate BCR after robotic-assisted radical prostatectomy (RARP) for clinically localized prostate cancer. We also analyzed correlation of BCR with pre-operative PSA level, D'Amico classification, pathological stage, post-operative GS, and positive surgical margins after RARP. Material and Methods: A total of 90 patients with clinically localized carcinoma prostate (≤ T 2), who underwent RARP between April 2012 and April 2017 at our institute with 3 year of minimum follow-up were included in our study. Patients having locally advanced disease on clinical staging or died of unrelated cause in follow up or lost to follow up were excluded from study. Patients who had persistent detectable PSA (> 0.20 ng/ml) at 6 week with a second confirmatory level of PSA greater than 0.2 ng/ml at 3rd month were excluded from study. Results: The age of the patient ranges from 46 to 79 years with the mean age of 65.36 ± 6.55 years. The mean PSA was 24.36 ± 26.68 ng/ml with range between 1.8 and 126.6 ng/ml. Nine patients (10%) developed BCR at 1-year follow-up and 81 patients were BCR-free. Thus, 1-year BCRFS and BCR rate were 90% and 10%, respectively in our study. Total 17 patients (18.9%) developed BCR during a 2-year period and 73 patients were free of BCR. Thus, 2-year BCRFS and BCR rate were 81.1% and 18.9%, respectively. A total of 29 patients (32.2%) had BCR and 61 patients were free of BCR at 3 years of follow-up. Thus, overall 3-year BCR rate and 3-year BCRFS rate were 32.2% and 67.8%, respectively. There was significant correlation of BCR with pre-operative PSA level, D'Amico classification, pathological stage, post-operative GS, and positive surgical margins. Conclusions: There is relative paucity of data regarding the BCR rate after RARP in the Indian scenario. The BCR rate in our study was similar to previously published Western and limited Indian data on RARP series in localized prostate cancer. There was significant correlation of BCR with PSA, post-operative GS, pathological stage, PSM, and D'Amico classification.

Right Laparoscopic Donor Nephrectomy: A Large-Volume, Single-Center Experience.

OBJECTIVES: The right kidney is not commonly selected for donor nephrectomy compared with the left kidney. Most left donor nephrectomies are performed by laparoscopic approach, whereas open donor nephrectomies are preferred on the right side. We present our experience of right laparoscopic donor nephrectomy, which was a substantial percentage of all performed laparoscopic donor nephrectomies. MATERIALS AND METHODS: We retrospectively analyzed all the donor nephrectomies performed at a single center, including indicators for right side open donor nephrectomy, as well as the demographic details of donors and intraoperative events, complications, and hospital stay for right side laparoscopic donor nephrectomy. Recipients were evaluated for outcome and complications. RESULTS: We performed 850 donor nephrectomies, including 640 left donor nephrectomies and 210 right donor nephrectomies. Of 210 right donor nephrectomies, 160 cases were performed laparoscopically, and 50 cases were open surgeries. Common indications for choice of right open donor nephrectomy were related to the donor. Factors related to the recipient included obesity, left iliac fossa transplant, and robotic transplant to the recipient. The surgical outcomes or complication rates in right side laparoscopic donor nephrectomy were not significantly different. Regarding recipients, we found that graft function, perioperative parameters, and vascular complications did not differ much in right side laparoscopic donor nephrectomy. CONCLUSIONS: The right side laparoscopic donor nephrectomy is as safe as left laparoscopic donor nephrectomy or right side open donor nephrectomy. Careful consideration of recipient factors is very important along with donor factors before opting for an open or laparoscopic approach on the right side. Slight modifications in technique may provide a few additional millimeters of length, which can significantly increase the incentive to choose laparoscopic donor nephrectomy on the right side.

Comparison of open, laparoscopic and robot-assisted pyeloplasty for pelviureteric junction obstruction in adult patients.

Ureteropelvic junction obstruction (UPJO) is a frequently found congenital abnormality of the upper urinary tract treated with pyeloplasty. We hereby report a study to compare open pyeloplasty (OP), laparoscopic pyeloplasty (LP) and robotic assisted pyeloplasty (RAP) for UPJO in terms of functional and perioperative outcomes. 102 patients who underwent Anderson-Hynes dismembered pyeloplasty for UPJO were divided into three groups based on type of surgical techniques utilized as follows: OP (Group A; n = 34), LP (Group B; n = 34), and RAP (Group C; n = 34). Preoperative, intraoperative and postoperative data were recorded. The mean operative time was significantly more in the Group B (187.76 min) than the Group A (132.06 ± 30.1 min) and Group C (136.76 ± 25.1 min) (p < .001). Mean blood loss was more in OP group 86.47 ± 29. 35 ml versus 42.94 ± 20. 77 ml in RAP and 45.59 ± 20. 3 ml in the LP group (p < .001). The LP was found to be much tiring. Mean surgeon fatigue index (SFI) calculated was 7 ± 1.1 in the LP group compared to 4.12 ± 1.1 in RAP group and the difference was statistically significant (p< .001). Average VAS score in the first 2 days postoperatively was 6.66±1.58 in the OP group compared to 4.29 ± 1.16 in RAP group and 4.29 ± 1.31 in the LP group (p < 0.001). Pyeloplasty has a similar success rate and efficacy irrespective of the technique utilized. RAP improves the surgeons QOL (quality of life) and the fatigue scores, which is useful for surgeon longevity. RAP has become widely favorite and can be considered the approach of choice in the management of UPJO wherever infrastructure and finances allow.

Prevalence of Age-Associated Testosterone Deficiency Syndrome in Indian Population.

Testosterone deficiency syndrome (TDS) is a gradual age-related phenomenon that occurs in a large proportion of the aging male population. This current prospective study was done with the objective to estimate the prevalence of age-associated TDS in India and its clinical profile. A total of 800 male patients aged ≥40 year were approached to participate in the study. A brief history and focused examination was done. Based on our exclusion criteria, 55 patients were excluded. Androgen deficiency in aging male (ADAM) questionnaire was administered to all remaining 745 patients. Out of these 745 patients, ADAM-positive (symptomatic TDS) patients were found to be 359 and enrolled in the study. In all ADAM-positive patients, serum testosterone levels were measured. Prevalence of symptomatic TDS in study population was found to be 48.18%. Mean total and free testosterone level of symptomatic TDS population were 3.287 ± 1.494 ng/ml (1.12-9.61) and 7.476 ± 2.902 pg/ml (2.18-21.76), respectively. Prevalence of biochemically confirmed TDS among symptomatic TDS population was 60.17%. Prevalence of TDS increases progressively with each decade of life (p=0.034). Prevalence was higher in patients with diabetes, hypertension, coronary artery disease, obesity, and metabolic syndrome. TDS is a real phenomenon with a prevalence of 28.99% in our study population.

Robot-assisted adrenalectomy: current perspectives.

Laparoscopy has established itself as the procedure of choice for performing adrenalectomy in benign adrenal disorders. Although laparoscopy scores heavily over open approach in terms of lesser blood loss, pain, shorter hospital stay and better cosmesis, it is riddled with certain shortcomings such as the need of dexterity, two-dimensional vision, dependence on an assistant for camera, etc. Robotic surgery promises to overcome these limitations. Multiple series have established that robotic adrenalectomy is a safe and effective procedure as conventional laparoscopy. Recently, robotic surgery has been found to be precise and accurate in performing partial adrenalectomy in hereditary adrenal syndrome cases. Other advances like single-port surgery have expanded the horizon and indications of robotic surgery. This review aims at studying the current evidence available for the effectiveness of robot-assisted adrenalectomy and defining its current status in managing adrenal disorders.

The impact of high grade glial neoplasms on human cortical electrophysiology.

OBJECTIVE: The brain's functional architecture of interconnected network-related oscillatory patterns in discrete cortical regions has been well established with functional magnetic resonance imaging (fMRI) studies or direct cortical electrophysiology from electrodes placed on the surface of the brain, or electrocorticography (ECoG). These resting state networks exhibit a robust functional architecture that persists through all stages of sleep and under anesthesia. While the stability of these networks provides a fundamental understanding of the organization of the brain, understanding how these regions can be perturbed is also critical in defining the brain's ability to adapt while learning and recovering from injury. METHODS: Patients undergoing an awake craniotomy for resection of a tumor were studied as a unique model of an evolving injury to help define how the cortical physiology and the associated networks were altered by the presence of an invasive brain tumor. RESULTS: This study demonstrates that there is a distinct pattern of alteration of cortical physiology in the setting of a malignant glioma. These changes lead to a physiologic sequestration and progressive synaptic homogeneity suggesting that a de-learning phenomenon occurs within the tumoral tissue compared to its surroundings. SIGNIFICANCE: These findings provide insight into how the brain accommodates a region of "defunctionalized" cortex. Additionally, these findings may have important implications for emerging techniques in brain mapping using endogenous cortical physiology.

Electrophysiological Sequelae of Hemispherotomy in Ipsilateral Human Cortex.

Objectives: Hemispheric disconnection has been used as a treatment of medically refractory epilepsy and evolved from anatomic hemispherectomy to functional hemispherectomies to hemispherotomies. The hemispherotomy procedure involves disconnection of an entire hemisphere with limited tissue resection and is reserved for medically-refractory epilepsy due to diffuse hemispheric disease. Although it is thought to be effective by preventing seizures from spreading to the contralateral hemisphere, the electrophysiological effects of a hemispherotomy on the ipsilateral hemisphere remain poorly defined. The objective of this study was to evaluate the effects of hemispherotomy on the electrophysiologic dynamics in peri-stroke and dysplastic cortex. Methods: Intraoperative electrocorticography (ECoG) was recorded from ipsilateral cortex in 5 human subjects with refractory epilepsy before and after hemispherotomy. Power spectral density, mutual information, and phase-amplitude coupling were measured from the ECoG signals. Results: Epilepsy was a result of remote perinatal stroke in three of the subjects. In two of the subjects, seizures were a consequence of dysplastic tissue: one with hemimegalencephaly and the second with Rasmussen's encephalitis. Hemispherotomy reduced broad-band power spectral density in peri-stroke cortex. Meanwhile, hemispherotomy increased power in the low and high frequency bands for dysplastic cortex. Functional connectivity was increased in lower frequency bands in peri-stroke tissue but not affected in dysplastic tissue after hemispherotomy. Finally, hemispherotomy reduced band-specific phase-amplitude coupling in peristroke cortex but not dysplastic cortex. Significance: Disconnecting deep subcortical connections to peri-stroke cortex via a hemispherotomy attenuates power of oscillations and impairs the transfer of information from large-scale distributed brain networks to the local cortex. Hence, hemispherotomy reduces heterogeneity between neighboring cortex while impairing phase-amplitude coupling. In contrast, dysfunctional networks in dysplastic cortex lack the normal connectivity with distant networks. Therefore hemispherotomy does not produce the same effects.

Decoding three-dimensional reaching movements using electrocorticographic signals in humans.

OBJECTIVE: Electrocorticography (ECoG) signals have emerged as a potential control signal for brain-computer interface (BCI) applications due to balancing signal quality and implant invasiveness. While there have been numerous demonstrations in which ECoG signals were used to decode motor movements and to develop BCI systems, the extent of information that can be decoded has been uncertain. Therefore, we sought to determine if ECoG signals could be used to decode kinematics (speed, velocity, and position) of arm movements in 3D space. APPROACH: To investigate this, we designed a 3D center-out reaching task that was performed by five epileptic patients undergoing temporary placement of ECoG arrays. We used the ECoG signals within a hierarchical partial-least squares (PLS) regression model to perform offline prediction of hand speed, velocity, and position. MAIN RESULTS: The hierarchical PLS regression model enabled us to predict hand speed, velocity, and position during 3D reaching movements from held-out test sets with accuracies above chance in each patient with mean correlation coefficients between 0.31 and 0.80 for speed, 0.27 and 0.54 for velocity, and 0.22 and 0.57 for position. While beta band power changes were the most significant features within the model used to classify movement and rest, the local motor potential and high gamma band power changes, were the most important features in the prediction of kinematic parameters. SIGNIFICANCE: We believe that this study represents the first demonstration that truly three-dimensional movements can be predicted from ECoG recordings in human patients. Furthermore, this prediction underscores the potential to develop BCI systems with multiple degrees of freedom in human patients using ECoG.

Robot assisted adrenalectomy: a handy tool or glorified obsession?

Robotic surgery has recently expanded its horizon in urology apart from radical prostatectomy, one of them being adrenalectomy. Till now, laparoscopic adrenalectomy has established itself as the procedure of choice for benign adrenal disorders. Brandao et al. have recently accomplished a thorough systematic review and meta-analysis of nine trials comparing laparoscopic and robotic adrenalectomy. There was no significant difference between the two groups in terms of conversion rate [odds ratio (OR): 0.82; 95% CI, 0.39-1.75; P=0.61] and operative time (WMD: 5.88; 95% CI, -6.02 to 17.79; P=0.33). There was a significantly longer hospital stay in the conventional laparoscopic group (WMD: -0.43; 95% CI, -0.56 to -0.30; P<0.00001), as well as a higher estimated blood loss (WMD: -18.21; 95% CI, -29.11 to -7.32; P=0.001). There was also no statistically significant difference in terms of postoperative complication rate. The authors seem to support the use of robot for adrenalectomy. However, robotic surgery suffers from cost issues and some technical drawbacks that limit its use in routine practice. Larger and appropriately powered randomized controlled trials are needed to establish and justify its use for performing adrenalectomy.

Optimizing the Detection of Wakeful and Sleep-Like States for Future Electrocorticographic Brain Computer Interface Applications.

Previous studies suggest stable and robust control of a brain-computer interface (BCI) can be achieved using electrocorticography (ECoG). Translation of this technology from the laboratory to the real world requires additional methods that allow users operate their ECoG-based BCI autonomously. In such an environment, users must be able to perform all tasks currently performed by the experimenter, including manually switching the BCI system on/off. Although a simple task, it can be challenging for target users (e.g., individuals with tetraplegia) due to severe motor disability. In this study, we present an automated and practical strategy to switch a BCI system on or off based on the cognitive state of the user. Using a logistic regression, we built probabilistic models that utilized sub-dural ECoG signals from humans to estimate in pseudo real-time whether a person is awake or in a sleep-like state, and subsequently, whether to turn a BCI system on or off. Furthermore, we constrained these models to identify the optimal anatomical and spectral parameters for delineating states. Other methods exist to differentiate wake and sleep states using ECoG, but none account for practical requirements of BCI application, such as minimizing the size of an ECoG implant and predicting states in real time. Our results demonstrate that, across 4 individuals, wakeful and sleep-like states can be classified with over 80% accuracy (up to 92%) in pseudo real-time using high gamma (70-110 Hz) band limited power from only 5 electrodes (platinum discs with a diameter of 2.3 mm) located above the precentral and posterior superior temporal gyrus.

A study to evaluate the effect of ratio of donor kidney weight to recipient body weight on renal graft function.

AIM AND OBJECTIVES: To study the effect of the ratio of donor kidney weight (dkw) to recipient body weight (rbw) on short and long term graft function in live donor kidney transplant patients. MATERIALS AND METHODS: It was a prospective study of 79 live donor kidney transplant recipients. Patients were divided into three groups depending on the ratio of dkw in grams to rbw in kilograms. Serum creatinine in milligrams percent on the day of surgery, 7(th) day, 1 month, 6 months, 1 year, and 3 years after the surgery was recorded and their means compared. RESULTS: The comparison showed that the decrease in mean creatinine level was more in group three patients as compared with group 2 and one patients at 7 days (1.04,1.44 and 1.59 in group 3,2 and 1 respectively) and 30 days (1.12,1.36 and 1.45 in group 3,2 and 1 respectively), showing that higher dkw/rbw ratio is beneficial with respect to the early graft function. However this decrease was not statistically significant (P value -0.256 and 0.358 respectively on 7(th) and 30(th) day). Furthermore long-term function was not different among these three groups. CONCLUSION: The ratio of dkw to rbw does not have a significant effect on long-term graft function inspite of an early improvement in the function with increased dkw to rbw ratio.