Three Sliding Probes Placed on Forelimb Skin for Proprioceptive Feedback Differentially yet Complementarily Contribute to Hand Gesture Detection and Object-Size Discrimination

The purpose was to assess the effectiveness of three sliding tactile probes placed on the forelimb skin to provide proprioceptive feedback for the detection of hand gestures and discrimination of object size. Tactile contactors representing the first three fingers were driven along the proximodistal axis by linear servo motors. Twenty healthy subjects were involved in the gesture detection test, with 10 of them also participating in the object-size discrimination task. Motors were controlled by computer in the first four sessions of the gesture detection experiment, while the fifth session utilized a sensorized glove. Both the volar and dorsal sides of the forearm were examined. In the object-size discrimination experiment, the method was exclusively assessed on the volar surface under four distinct feedback conditions, including all fingers and each finger separately. The psychophysical data were further analyzed using a structural equation model (SEM) to evaluate the specific contributions of each individual contactor. Subjects consistently outperformed the chance level in detecting gestures. Performance improved up to the third session, with better results obtained on the volar side. The performances were similar in the fourth and fifth sessions. The just noticeable difference for achieving a 75% discrimination accuracy was found to be 2.90 mm of movement on the skin. SEM analysis indicated that the contactor for the index finger had the lowest importance in gesture detection, while it played a more significant role in object-size discrimination. However, all fingers were found to be significant predictors of subjects' responses in both experiments, except for the thumb, which was deemed insignificant in object-size discrimination. The study highlights the importance of considering the partial contribution of each degree of freedom in a sensory feedback system, especially concerning the task, when designing such systems.

Transperineal microwave thermoablation for benign prostatic hyperplasia-related lower urinary tract symptoms in an elderly patient

Transperineal prostate microwave thermoablation (TPMT) has been established as a safe means of treating benign prostatic hyperplasia (BPH); however, its effectiveness in addressing BPH-related lower urinary tract symptoms (LUTS) remains unexplored. This case study aims to evaluate the efficacy of TPMT in LUTS attributed to BPH. An 84-year-old man with LUTS due to BPH-induced bladder outlet obstruction, unresponsive to previous medical treatments, and failed prostate artery embolization, underwent TPMT. Three coaxial needles were positioned at the midline, right, and left sides of the hypertrophic transitional zone of the prostate. Microwave energy, with parameters determined using liver data and targeted ablation area, was applied at 2,450 MHz in continuous mode. The tissue temperature was monitored using bilateral thermocouple sensors. The patient exhibited no changes in defecation rhythm, abdominal discomfort, or anorectal pain. Temporary postoperative hematuria was promptly resolved through saline irrigation within 6 hours, and hematological evaluations showed normal results. Significant clinical improvements were observed (e.g., prostate volume, prostate-specific antigen levels) accompanied by an increase in peak flow rate. Thus, TPMT appears to be a promising intervention for bladder outlet stenosis and LUTS induced by BPH.

ROI-based analysis of diffusion indices in healthy subjects and subjects with deficit or non-deficit syndrome schizophrenia

We analyzed DTI data involving 22 healthy subjects (HC), 15 patients with deficit syndrome schizophrenia (DSZ), and 25 patients with non-deficit syndrome schizophrenia (NDSZ). We used a 1.5-T MRI scanner to collect diffusion-weighted images and T1 images, which were employed to correct distortions and deformations within the diffusion-weighted images. For 156 regions of interest (ROI), we calculated the average fractional anisotropy (FA), mean diffusion (MD), and radial diffusion (RD). Each ROI underwent a group-wise comparison using permutation F-test, followed by post hoc pairwise comparisons with Bonferroni correction. In general, we observed lower FA in both schizophrenia groups compared to HC (i.e., HC>(DSZ=NDSZ)), while MD and RD showed the opposite pattern. Notably, specific ROIs with reduced FA in schizophrenia patients included bilateral nucleus accumbens, left fusiform area, brain stem, anterior corpus callosum, left rostral and caudal anterior cingulate, right posterior cingulate, left thalamus, left hippocampus, left inferior temporal cortex, right superior temporal cortex, left pars triangularis and right lingual gyrus. Significantly, the right cuneus exhibited lower FA in the DSZ group compared to other groups ((HC=NDSZ)>DSZ), without affecting MD and RD. These results indicate that compromised neural integrity in the cuneus may contribute to the pathophysiological distinctions between DSZ and NDSZ.

Tunneled Uncuffed Pigtail Drainage Catheter Placement in Patients with Refractory Ascites or Pleural Effusion: A Single-Center Experience

PURPOSE

No evidence exists to support the use of tunneled non-cuffed pigtail drainage catheters in patients with refractory ascites or pleural effusion. The purpose of this study was to determine the feasibility of non-cuffed tunneled pigtail drainage catheters in patients with refractory ascites or pleural effusions.

MATERIALS AND METHODS

Between October 5, 2020 and May 25, 2021, 34 pigtail catheters were implanted in 27 patients (17 males, 10 females; average age: 65.66 ± 12.04 years) under either ultrasound or computed-tomography guidance (19 catheters for ascites, 15 catheters for pleural effusion). Twenty-eight catheters (82.35%) were implanted for malignant etiologies, and 6 catheters (17.65%) were implanted for benign etiologies. The catheters (size: 8-14 French) were implanted through a subcutaneous tunnel. Complication rate and factors related to complications were analyzed. Catheter lifetime was analyzed with Kaplan-Meier method.

RESULTS

Patency ranged from 3 to 211 days. None of the patients experienced a major complication (e.g., peritonitis and empyema). Meanwhile, 8 minor complications were observed including 3 catheter occlusion, 3 ascites leakage, 1 peri-catheter local skin infection, 1 peri-catheter local skin reaction. None of the etiologies were related to the catheter complications. However, the 8-F catheter was associated with a significantly higher complication rate (odds = 5.5, p = 0.044). The estimated mean [CI] dwelling time of a catheter was 59.18 [32.97, 85.39] days.

CONCLUSIONS

Image-guided insertion of tunneled peritoneal or pleural pigtail external drainage catheters achieved with a 100% technical success rate and resulted in an acceptable complication rate and catheter lifetime for the management of refractory ascites or pleural effusion.

Psychophysical Evaluation of Proprioceptive Feedback Through a Probe Sliding on the Forearm Skin of Healthy Humans

We have tested the forearm skin of humans as a target organ to deliver proprioceptive feedback via a tactile sensory substitution method. In the proposed method, a contactor probe was actuated by a linear servo motor and moved on the skin in proximo-distal axis depending on the angle of a virtual joint moving on a 180° arc. Twenty healthy subjects were tested to stop the joint at a given target under no-feedback, visual feedback, and tactile (dorsal and volar) feedback conditions. The absolute difference between the target and the response angle was recorded. Tests were repeated 4 times with ~ 1-week intervals. Two joint movement speeds were tested. The subjects performed best with visual feedback, and worst if no feedback was provided. Their performances with tactile feedback were not as good as in the visual feedback condition, but better than in the no-feedback condition. Subjects equally performed with volar and dorsal tactile feedback. The movement speed had no significant effects on tactile feedback. The performance improved with training only in tactile feedback conditions. The proprioceptive information from a motorized prosthesis can be provided through probes moving on the forearm skin, while the efficacy of the feedback may improve with extensive training.

Mechanical Impedance of Rat Glabrous Skin and Its Relation With Skin Morphometry

The mechanical impedance of intact and epidermis-peeled rat glabrous skin was studied at two sites (digit and sole) and at two frequencies (40 Hz and 250 Hz). The thicknesses of skin layers at the corresponding regions were measured histologically from intact- and peeled-skin samples in every subject. Compared to intact sole skin, digital rat skin has thicker layers and higher mechanical resistance, and it is less stiff. The resistance of the skin significantly decreased after epidermal peeling at both the digit and the sole. Furthermore, peeling caused the reactance to become positive due to inertial effects. As the frequency was increased from 40 to 250 Hz, the resistance and stiffness also increased for the intact skin, while the peeled skin showed less frictional (i.e., resistance) but more inertial (i.e., positive reactance) effects. We estimated the mechanical properties of epidermis and dermis with lumped-element models developed for both intact and peeled conditions. The models predicted that dermis has higher mass, lower stiffness, and lower resistance compared to epidermis, similar to the experimental impedance results obtained in the peeled condition which consisted mostly of dermis. The overall impedance was simulated more successfully at 40 Hz. When both frequencies are considered, the models produced consistent results for resistance in both conditions. The results imply that most of the model parameters should be frequency-dependent and suggest that mechanical properties of epidermis can be related to its thickness. These findings may help in designing artificial skin for neuroprosthetic limbs.

A Retrospective Analysis of the Effectiveness of Extrapleural Autologous Blood Patch Injection on Pneumothorax and Intervention Need in CT-guided Lung Biopsy

PURPOSE

To assess the effect of extrapleural autologous blood injection (EPABI) technique on pneumothorax development before and after coaxial needle withdrawal (CNW) and intervention rate for pneumothorax. To analyze the risk factors of pneumothorax and parenchymal hemorrhage.

MATERIALS AND METHODS

The records of 288 patients who had lung biopsies were analyzed. Of these patients, 188 received EPABI (group-A) before penetrating the parietal pleura, and the remaining did not (group-B). Intraparenchymal autologous blood patch injection was applied at the end of the procedure. The pneumothorax rates before/after CNW and intervention requirement for pneumothorax were compared between groups. The risk factors of pneumothorax before/after CNW and parenchymal hemorrhage were assessed with stepwise logistic regression.

RESULTS

The pneumothorax rate before CNW was significantly lower in group-A (5.92%) than in group-B (19.10%) (p = 0.029). Pneumothorax risk before CNW was reduced if EPABI was applied and skin-to-pleura distance increased. The pneumothorax rate after CNW was similar between two groups (group-A: 6.94%, group-B: 8%), while emphysema grade along the needle path and procedure duration was the significant risk factor. The intervention requirement for pneumothorax was significantly lower in group-A (6.38%) than in group-B (16%) (p = 0.012). Needle aspiration requirement was significantly reduced in group-A. The rate of external drainage catheter and chest tube placement was similar in both groups. The risk factors of parenchymal hemorrhage were overall emphysema grade of the lung, target-to-pleura distance, and target size.

CONCLUSION

Use of EPABI along with IAPBI significantly decreased the pneumothorax rate during biopsy procedure and the intervention rate compared to IAPBI-alone.

Correction to: Psychophysical detection and learning in freely behaving rats: a probabilistic dynamical model for operant conditioning

The original version of this article unfortunately has some typographical errors in equations (5), (6), (7), (8), and (12).

Novel Use of Extrapleural Autologous Blood Injection in CT-Guided Percutaneous Lung Biopsy and its Comparison to Intraparenchymal Autologous Blood Patch Injection: A Single-Center, Prospective, Randomized, and Controlled Clinical Trial

PURPOSE

To evaluate the rate of iatrogenic pneumothorax and the need for intervention with extrapleural autologous blood injection (EPABI) along with intraparenchymal autologous blood patch injection (IABPI) or IABPI-only in CT-guided percutaneous lung biopsy.

MATERIALS AND METHODS

One hundred and thirty-nine participants were referred for CT-guided percutaneous lung biopsy, and 81 were randomized into study (EPABI + IABPI, n = 40) and control (IABPI-only, n = 41) groups. In the study group, ~5 ml of autologous blood was injected into the extrapleural space before passing through the parietal and visceral pleura. The primary outcome was the incidence of pneumothorax in two cohorts within 2 weeks after the procedure.

RESULTS

In the per-protocol population, pneumothorax rates were 5.9% and 25.7% in the study and control groups, respectively. The difference between the two groups was -19.8% (95% CI: -36.3%, 3.32%) (p = 0.025). On the other hand, in the population with no intraprocedural deviations, pneumothorax rates were 3.2% and 17.2% in the study and control groups, respectively. The difference between the two groups was -14.0% (95% CI: -29.1%, 1.07%) (p = 0.083). In the control group, 3.45% of the cases required aspiration, while no intervention was required in the study group.

CONCLUSION

The EPABI application along with IABPI is a promising method to decrease the incidence of pneumothorax following CT-guided percutaneous lung biopsy.

Psychophysical detection and learning in freely behaving rats: a probabilistic dynamical model for operant conditioning

We present a stochastic learning model that combines the essential elements of Hebbian and Rescorla-Wagner theories for operant conditioning. The model was used to predict the behavioral data of rats performing a vibrotactile yes/no detection task. Probabilistic nature of learning was implemented by trial-by-trial variability in the random distributions of associative strengths between the sensory and the response representations. By using measures derived from log-likelihoods (corrected Akaike and Bayesian information criteria), the proposed model and its subtypes were compared with each other, and with previous models in the literature, including reinforcement learning model with softmax rule and drift diffusion model. The main difference between these models was the level of stochasticity which was implemented as associative variation or response selection. The proposed model with subject-dependent variance coefficient (SVC) and with trial-dependent variance coefficient (TVC) resulted in better trial-by-trial fits to experimental data than the other tested models based on information criteria. Additionally, surrogate data were simulated with estimated parameters and the performance of the models were compared based on psychophysical measures (A': non-parametric sensitivity index, hits and false alarms on receiver operating characteristics). Especially the TVC model could produce psychophysical measures closer to those of the experimental data than the alternative models. The presented approach is novel for linking psychophysical response measures with learning in a yes/no detection task, and may be used in neural engineering applications.

Psychophysical correspondence between vibrotactile intensity and intracortical microstimulation for tactile neuroprostheses in rats

OBJECTIVE

Recent studies showed that intracortical microstimulation (ICMS) generates artificial sensations which can be utilized as somatosensory feedback in cortical neuroprostheses. To mimic the natural psychophysical response, ICMS parameters are modulated according to psychometric equivalence functions (PEFs). PEFs match the intensity levels of ICMS and mechanical stimuli, which elicit equal detection probabilities, but they typically do not include the frequency as a control variable. We aimed to establish frequency-dependent PEFs for vibrotactile stimulation of the glabrous skin and ICMS in the primary somatosensory cortex of awake freely behaving rats.

APPROACH

We collected psychometric data for vibrotactile and ICMS detection at three stimulation frequencies (40, 60 and 80 Hz). The psychometric data were fitted with a model equation of two independent variables (stimulus intensity and frequency) and four subject-dependent parameters. For each rat, we constructed a separate PEF which was used to estimate the ICMS current amplitude for a given displacement amplitude and frequency. The ICMS frequency was set equal to the vibrotactile frequency. We validated the PEFs in a modified task which included randomly selected probe trials presented either with a vibrotactile or an ICMS stimulus, and also at frequencies and intensity levels not tested before.

MAIN RESULTS

The PEFs were generally successful in estimating the ICMS current intensities (no significant differences between vibrotactile and ICMS trials in Kolmogorov-Smirnov tests). Specifically, hit rates from both trial conditions were significantly correlated in 86% of the cases, and 52% of all data had perfect match in linear regression.

SIGNIFICANCE

The psychometric correspondence model presented in this study was constructed based on surface functions which define psychophysical detection probability as a function of stimulus intensity and frequency. Therefore, it may be used for the real-time modulation of the frequency and intensity of ICMS pulses in somatosensory neuroprostheses.