A review on model-based and model-free approaches to control soft actuators and their potentials in colonoscopy.

Colorectal cancer (CRC) is the third most common cancer worldwide and responsible for approximately 1 million deaths annually. Early screening is essential to increase the chances of survival, and it can also reduce the cost of treatments for healthcare centres. Colonoscopy is the gold standard for CRC screening and treatment, but it has several drawbacks, including difficulty in manoeuvring the device, patient discomfort, and high cost. Soft endorobots, small and compliant devices thatcan reduce the force exerted on the colonic wall, offer a potential solution to these issues. However, controlling these soft robots is challenging due to their deformable materials and the limitations of mathematical models. In this Review, we discuss model-free and model-based approaches for controlling soft robots that can potentially be applied to endorobots for colonoscopy. We highlight the importance of selecting appropriate control methods based on various parameters, such as sensor and actuator solutions. This review aims to contribute to the development of smart control strategies for soft endorobots that can enhance the effectiveness and safety of robotics in colonoscopy. These strategies can be defined based on the available information about the robot and surrounding environment, control demands, mechanical design impact and characterization data based on calibration.

Self-supervised monocular depth estimation for high field of view colonoscopy cameras.

Optical colonoscopy is the gold standard procedure to detect colorectal cancer, the fourth most common cancer in the United Kingdom. Up to 22%-28% of polyps can be missed during the procedure that is associated with interval cancer. A vision-based autonomous soft endorobot for colonoscopy can drastically improve the accuracy of the procedure by inspecting the colon more systematically with reduced discomfort. A three-dimensional understanding of the environment is essential for robot navigation and can also improve the adenoma detection rate. Monocular depth estimation with deep learning methods has progressed substantially, but collecting ground-truth depth maps remains a challenge as no 3D camera can be fitted to a standard colonoscope. This work addresses this issue by using a self-supervised monocular depth estimation model that directly learns depth from video sequences with view synthesis. In addition, our model accommodates wide field-of-view cameras typically used in colonoscopy and specific challenges such as deformable surfaces, specular lighting, non-Lambertian surfaces, and high occlusion. We performed qualitative analysis on a synthetic data set, a quantitative examination of the colonoscopy training model, and real colonoscopy videos in near real-time.

Endorobots for Colonoscopy: Design Challenges and Available Technologies.

Colorectal cancer (CRC) is the second most common cause of cancer death worldwide, after lung cancer (Sung et al., 2021). Early stage detection is key to increase the survival rate. Colonoscopy remains to be the gold standard procedure due to its dual capability to optically inspect the entire colonic mucosa and to perform interventional procedures at the same time. However, this causes pain and discomfort, whereby it requires sedation or anaesthesia of the patient. It is a difficult procedure to perform that can cause damage to the colonic wall in some cases. Development of new technologies aims to overcome the current limitations on colonoscopy by using advancements in endorobotics research. The design of these advanced medical devices is challenging because of the limited space of the lumen, the contorted shape, and the long tract of the large bowel. The force applied to the colonic wall needs to be controlled to avoid collateral effects such as injuries to the colonic mucosa and pain during the procedure. This article discusses the current challenges in the colonoscopy procedure, the available locomotion technologies for endorobots used in colonoscopy at a prototype level and the commercial products available.

A Soft Pneumatic Inchworm Double balloon (SPID) for colonoscopy.

The design of a smart robot for colonoscopy is challenging because of the limited available space, slippery internal surfaces, and tortuous 3D shape of the human colon. Locomotion forces applied by an endoscopic robot may damage the colonic wall and/or cause pain and discomfort to patients. This study reports a Soft Pneumatic Inchworm Double balloon (SPID) mini-robot for colonoscopy consisting of two balloons connected by a 3 degrees of freedom soft pneumatic actuator. SPID has an external diameter of 18 mm, a total length of 60 mm, and weighs 10 g. The balloons provide anchorage into the colonic wall for a bio-inspired inchworm locomotion. The proposed design reduces the pressure applied to the colonic wall and consequently pain and discomfort during the procedure. The mini-robot has been tested in a deformable plastic colon phantom of similar shape and dimensions to the human anatomy, exhibiting efficient locomotion by its ability to deform and negotiate flexures and bends. The mini-robot is made of elastomer and constructed from 3D printed components, hence with low production costs essential for a disposable device.

The association of cognitive reserve with motor and cognitive functions for different stages of Parkinson's disease.

INTRODUCTION: The cognitive reserve (CR) theory has been proposed to account for the mismatch between the degree of neuropathological changes and clinical outcome in dementias. Recently, it has also been applied to Parkinson's disease (PD) with promising results, but mostly just focusing on separate proxy measures of CR, such as education, working and leisure time activities, instead of adopting a more comprehensive approach. Using the Cognitive Reserve Index questionnaire (CRIq), this study examined the association of CR with motor functions and cognition in patients with medium-low (1-9 years) and medium-high (>9 years) PD duration. METHODS: Fifty patients with PD underwent a neurological and a neuropsychological assessment, comprised of: Unified Parkinson's Disease Rating Scale- section III, Mini-Mental State Examination, Clock-Drawing Test, Rey auditory verbal learning test (immediate and delayed recall trials), Digit Span Forward, Corsi Span Forward, Frontal Assessment Battery, Raven's Colored Progressive Matrices, WAIS similarities subtest, Phonemic Fluency, Semantic Fluency and CRIq. RESULTS: PD patients with a higher CRIq score showed a reduced motor impairment and a better global cognitive performance when compared to PD patients with a lower CRIq score, with an advantage especially observed on executive functions and short-term memory. The CR effect was even enhanced in the case of longer disease duration, as observed when considering the overall neuropsychological tests performance and non-verbal abstract reasoning in particular. The results obtained when considering education, as a single proxy measure of CR, provided no additional findings, nor did they reveal all the effects yielded by the adoption of the CRI score. CONCLUSION: Our results support the beneficial role of CR against motor and cognitive dysfunctions in PD and suggest that its protective role may be mostly manifested at the later stages of the disease. A theoretical framework able to explain the different impact of CR on Alzheimer Disease and PD is discussed. Finally, our results stressed the importance of using a comprehensive measure of CR instead of focusing on just one of its proxies.

Design of a 2 DOFs Mini Hollow Joint Actuated with SMA Wires.

Shape memory alloys (SMAs) are smart materials used in robotics because of its light weight and high force-to-weight ratio. The low energy efficiency, up to 5%, has limited their use for large actuators. However, they have shown advantages in the design of mini-robots because of the limited volume required for the actuation system. The present study reports the design and construction of a mini compliant joint (MCJ) with a 2 degrees of freedom (DOFs) intersecting axis. The MCJ prototype has a 20 mm external diameter surrounding a cavity of 8 mm, weighs 2 g, is 20 mm high and can perform an angle rotation of 30 ∘ in less than 260 ms. It uses SMA NiTi wires in antagonistic configuration and springs to reduce the energy consumption and minimise heat production. The design methods and experimental results of the manufactured prototype are reported and discussed.

Delayed Gastric Emptying in Advanced Parkinson Disease: Correlation With Therapeutic Doses.

INTRODUCTION: Gastrointestinal dysfunction is often described in patients with Parkinson disease (PD), and gastrointestinal symptoms are usually attributed to gastroparesis. The consequent delayed gastric emptying (GE) may be an important pharmacokinetic mechanism underlying some of the response fluctuations that develop after long-term levodopa (L-dopa) therapy.The aim of this prospective study was to assess GE time by a liquid meal scintigraphy, in PD patients, and to correlate them with demographic, clinical, and therapeutic data. METHODS: Scintigraphy with radiolabeled albumin nanocolloids added to acidified orange juice was performed in 51 consecutive PD patients 1 hour after their usual dopaminergic therapy first dose and after a 12-hour fast. Demographic, neurologic, gastrointestinal, and pharmacologic data were collected. RESULTS: Fifty-one patients were divided into 2 groups using the cutoff point obtained in normal subjects (40 minutes): group 1 included 29 patients with GE T½ of 27.60 ± 7.30 minutes (normal), group 2 showed a GE T½ of 84.90 ± 53.80 minutes (delayed). The most striking significant difference between the 2 groups was the dopa-decarboxylase inhibitor mean dose that was significantly higher in the group of patients with delayed GE (201.32 ± 97.26 vs 127.65 ± 79.74; P = 0.005). CONCLUSIONS: The impairment of gastric motility, frequently represented in PD patients, occurs in approximately 42% of patients with motor complications. A mechanism that may explain the GE delay is the effect of L-dopa on dopaminergic receptors in the stomach. Therefore, the dosage of dopa-decarboxylase inhibitor, increasing the L-dopa concentration, may contribute to GE delay and its consequent effect on drug delivery and efficacy.

Image-based 3D modeling and validation of radiofrequency interstitial tumor ablation using a tissue-mimicking breast phantom.

PURPOSE: Minimally invasive treatment of solid cancers, especially in the breast and liver, remains clinically challenging, despite a variety of treatment modalities, including radiofrequency ablation (RFA), microwave ablation or high-intensity focused ultrasound. Each treatment modality has advantages and disadvantages, but all are limited by placement of a probe or US beam in the target tissue for tumor ablation and monitoring. The placement is difficult when the tumor is surrounded by large blood vessels or organs. Patient-specific image-based 3D modeling for thermal ablation simulation was developed to optimize treatment protocols that improve treatment efficacy. METHODS: A tissue-mimicking breast gel phantom was used to develop an image-based 3D computer-aided design (CAD) model for the evaluation of a planned RF ablation. First, the tissue-mimicking gel was cast in a breast mold to create a 3D breast phantom, which contained a simulated solid tumor. Second, the phantom was imaged in a medical MRI scanner using a standard breast imaging MR sequence. Third, the MR images were converted into a 3D CAD model using commercial software (ScanIP, Simpleware), which was input into another commercial package (COMSOL Multiphysics) for RFA simulation and treatment planning using a finite element method (FEM). For validation of the model, the breast phantom was experimentally ablated using a commercial (RITA) RFA electrode and a bipolar needle with an electrosurgical generator (DRE ASG-300). The RFA results obtained by pre-treatment simulation were compared with actual experimental ablation. RESULTS: A 3D CAD model, created from MR images of the complex breast phantom, was successfully integrated with an RFA electrode to perform FEM ablation simulation. The ablation volumes achieved both in the FEM simulation and the experimental test were equivalent, indicating that patient-specific models can be implemented for pre-treatment planning of solid tumor ablation. CONCLUSION: A tissue-mimicking breast gel phantom and its MR images were used to perform FEM 3D modeling and validation by experimental thermal ablation of the tumor. Similar patient-specific models can be created from preoperative images and used to perform finite element analysis to plan radiofrequency ablation. Clinically, the method can be implemented for pre-treatment planning to predict the effect of an individual's tissue environment on the ablation process, and this may improve the therapeutic efficacy.

Duodenal levodopa infusion for advanced Parkinson's disease: 12-month treatment outcome.

We assessed prospectively clinical and quality of life changes in 9 patients with Parkinson's disease (PD; H&Y > or = 3) with severe motor fluctuations and dyskinesia who started continuous daily levodopa duodenal infusion through percutaneous endoscopic gastrostomy. Seven patients completed the follow-up period. Duration of "off" periods and time with disabling dyskinesia shortened significantly in all patients (P < 0.01). Total daily dose of levodopa infused did not differ from baseline equivalents. There were significant improvements in UPDRS-II (activities of daily living) and -IV (motor complications) in the "on" condition (P < 0.02), and in four PDQ-39 domains (mobility, activities of daily living, stigma, bodily discomfort; P < 0.05). Two patients withdrew for adverse events. Our results demonstrate that a satisfactory therapeutic window can be achieved and maintained for several months in advanced PD patients.

Reliability of the El Escorial diagnostic criteria for amyotrophic lateral sclerosis.

BACKGROUND: The El Escorial diagnostic criteria are the most commonly used in clinical studies and therapeutic trials in patients with amyotrophic lateral sclerosis (ALS). The accuracy of the El Escorial criteria was tested in clinical practice, but the reliability is unknown when the diagnosis of ALS must be assessed on the basis of medical records. OBJECTIVE: To assess the reliability of the El Escorial criteria for the diagnosis of ALS in different settings. DESIGN AND METHODS: Semistructured forms were used to include the main diagnostic information on 20 patients with definite (n = 6), probable (n = 6), possible (n = 6), and suspected ALS (n = 2) and 19 patients with clinical conditions considered in the differential diagnosis. Agreement was tested by comparing the diagnosis made by the attending physician (the 'gold standard') with that of 4 raters with different backgrounds: a teaching neurologist with research and practical experience in the field of motor neuron disorders, a neurologist with specific interest in motor neuron disorders and neurophysiological background, a neurophysiologist, and a general neurologist with only occasional ALS patients. Sources of disagreement were discussed and the agreement was tested further on the medical records of 98 additional cases taken from an ongoing ALS registry. Eight additional cases (ALS: 4; other conditions: 4) were examined directly by the 4 raters. RESULTS: The interrater agreement on the medical records was poor (overall kappa 0.05-0.29). When the differential diagnosis was made between ALS (all diagnostic levels) and other conditions, interrater agreement was at best modest, with moderate variations when raters were compared in pairs (kappa 0.03-0.58) and when each rater was compared with the physician (kappa 0.27-0.51). Agreement was higher after direct examination of the patients (kappa 0.33-1) and increased significantly on the medical records after training (overall kappa 0.52-0.79). However, concordance was low (overall kappa 0.08-0.36), even after training, at the lowest diagnostic level (definite to suspected ALS vs. other conditions). CONCLUSIONS: The El Escorial criteria are a poor diagnostic indicator when patients' records are examined. Although medical education significantly improves the reliability of the criteria, concordance is still modest when the diagnosis includes suspected ALS.