| 1. |
- Vikström, Pernilla, et al.
(författare)
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Atypical sensory processing pattern following median or ulnar nerve injury - A case-control study
- 2018
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Ingår i: BMC Neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Due to brain plasticity a transection of a median or ulnar nerve results in profound changes in the somatosensory areas in the brain. The permanent sensory deprivation after a peripheral nerve injury might influence the interaction between all senses. The aim of the study was to investigate if a median and/or ulnar nerve injury gives rise to a changed sensory processing pattern. In addition we examined if age at injury, injured nerve or time since injury influence the sensory processing pattern. Methods: Fifty patients (40 men and 10 women, median age 43) operated due to a median and/or ulnar nerve injury were included. The patients completed the Adolescent/Adult Sensory Profile questionnaire, which includes a comprehensive characterization on how sensory information is processed and how an individual responds to multiple sensory modalities. AASP categorizes the results into four possible Quadrants of behavioral profiles (Q1-low registration, Q2-sensory seeking, Q3-sensory sensitivity and Q4-sensory avoiding). The results were compared to 209 healthy age and gender matched controls. Anova Matched Design was used for evaluation of differences between the patient group and the control group. Atypical sensory processing behavior was determined in relation to the normative distribution of the control group. Results: Significant difference was seen in Q1, low registration. 40% in the patient group scored atypically in this Quadrant compared to 16% of the controls. No correlation between atypical sensory processing pattern and age or time since injury was seen. Conclusion: A peripheral nerve injury entails altered sensory processing pattern with increased proportion of patients with low registration to sensory stimulus overall. Our results can guide us into more client centered rehabilitation strategies.
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| 2. |
- Engstrand, Christina
(författare)
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Hand function in patients with Dupuytren’s disease : Assessment, results & patients’ perspectives
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Dupuytren’s Disease (DD) is a soft tissue disorder that leads to finger joint contractures affecting hand function. DD can be treated with surgery or injection and hand therapy to improve finger joint extension and thereby improve hand function. However, this does not cure the disease and recurrence is common. Previous research on DD has shown improvement in finger joint extension and in self-reported disability of the upper extremity after surgery and hand therapy for DD. However, this provides only a limited perspective on hand function, and multiple dimensions of changes in hand function (i.e. physical, psychosocial aspects and including the patients’ views of results) have not been reported as a whole.Aim: The overall aim of the thesis was to explore hand function before and after surgery and hand therapy in patients with DD, including assessment, results and patients’ perspectives.Methods: The thesis comprises three studies: Study A was a methodological study of interrater reliability in goniometry of the finger joints. Study B was a prospective cohort study with a repeated measures design. Study C was a qualitative interview study, using the model of Patient Evaluation Process and content analysis.Results: Interrater reliability was high or very high for goniometer measurement of finger joint range of motion (ROM) in patients with DD when experienced raters follow our standardized guidelines developed for the study. Changes in hand function consisted of improvement of finger joint extension while active finger flexion was significantly impaired during the first year after surgery and hand therapy. No patient reached a normal ROM, but the majority reached a functional ROM. Sensibility remained unaffected. Patients with surgery on multiple fingers had worse scar pliability than patients with surgery on a single finger. Most patients had their expectations met and were pleased or delighted with their hand function at 12 months after surgery and hand therapy. Safety issues of hand function were of greater concern than social issues. Patients reported less disability and improved health-related quality of life after surgery and hand therapy. The three variables “need to take special precautions”, “avoid using the hand in social context”, and health-related quality of life had significant importance for patients’ rating of functional recovery. Together, these variables explained 62% of the variance in functional recovery. Patients’ perspectives of undergoing a surgical intervention process were described through five categories. Previous experiences of care influenced participants’ expectations of results and the care they were about to receive. Previous experiences and expectations were used as references for appraisal of results, which concerned perceived changes in hand function, the care process, competency, and organization. Appraisal of results could also vary in relation to patient character. Appraisal of results of the intervention process influenced participants’ expectations of future hand function, health and care.Conclusions: Surgery and hand therapy for DD improve hand function and patients regain a functional ROM needed for performance of common daily activities. Despite the negative effect on finger flexion present during the first year after surgery, patients’ regards their hand function as recovered six to eight months after surgery and hand therapy. Measuring digital ROM in the finger joints with a goniometer is a reliable assessment method. However, from the patient’s perspective, it is not enough to evaluate results only in terms of digital extension or ROM. From their view, results of treatment concern consequences on daily use of the hand, what happens during the care process in terms of interaction between patient and health care provider, as well as their view of the competence and logistics of the organization providing the care.
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| 3. |
- Lundborg, Göran, et al.
(författare)
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Cutaneous anaesthesia of the lower leg can improve sensibility in the diabetic foot. A double-blind, randomized clinical trial
- 2010
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Ingår i: Diabetic Medicine. - : Wiley. - 1464-5491 .- 0742-3071. ; 27:7, s. 823-829
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Tidskriftsartikel (refereegranskat)abstract
- P>Aims Impaired sensory function in the sole of the foot in diabetic patients is a substantial problem caused by unknown mechanisms. Hand or foot sensibility can be improved by cutaneous anaesthesia of the forearm or lower leg, respectively, in healthy subjects. Hypothetically, cutaneous anaesthesia induces a silent area in the primary somatosensory cortex, allowing adjacent cortical areas to expand; thus, resulting in enhanced sensory processing. Our aim was to improve sensory function in the foot in Type 1 and Type 2 diabetic patients by application of an anaesthetic cream to the lower leg. Methods In a double-blind study, 37 patients with Type 1 or Type 2 diabetes were randomly assigned to cutaneous application of either an anaesthetic cream (EMLA (R)) or a placebo cream to the skin of the lower leg for 1.5 h. Sensibility at five points of the sole of the foot was assessed before and after 1.5 and 24 h. Vibrotactile sense was also assessed. Primary outcome was change of touch threshold at the first metatarsal head from pretreatment to 1.5 h assessment. Results Anaesthetic cream on the lower leg resulted in a significant improvement of touch threshold at the first metatarsal head after 1.5 and 24 h. In addition, improvement of touch thresholds was also observed at the other four assessment sites, together with a decreased vibration threshold at 125 Hz. Conclusions The findings of improved touch thresholds open up new possibilities in treatment of sensibility disturbances in the diabetic foot, using a simple and non-invasive method.
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| 4. |
- Björkman, Anders, et al.
(författare)
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Cortical sensory and motor response in a patient whose hand has been replanted: One-year follow up with functional magnetic resonance imaging
- 2007
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Informa UK Limited. - 1651-2073 .- 0284-4311. ; 41:2, s. 70-76
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Tidskriftsartikel (refereegranskat)abstract
- Functional magnetic resonance imaging (fMRI) was used to study how a replanted hand regained its cortical territory parallel to recovery. The cortical response to sensory stimulation shifts from an ipsilateral to a bilateral pattern, and then to a predominantly contralateral activation. The cortical response to motor stimulation was normal from the first investigation.
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| 5. |
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| 6. |
- Antfolk, Christian, et al.
(författare)
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A Tactile Display System for Hand Prostheses to Discriminate Pressure and Individual Finger Localization
- 2010
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Ingår i: Journal of Medical and Biological Engineering. - : Taiwanese Society of Biomedical Engineering. - 1609-0985. ; 30:6, s. 355-359
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Tidskriftsartikel (refereegranskat)abstract
- No current commercially available myoelectrically controlled prosthetic hands provide conscious sensory feedback to the user. A system aiming at relocation of sensory input from a prosthetic hand equipped with force sensors to the forearm skin of amputees, a tactile display, has been developed and constructed. The system consists of five piezoresistive force sensors or, alternatively, a prosthetic hand equipped with force sensors, five digital servomotors with a lever and a circular plastic disk pushing on the skin, control electronics based on an MSP430 microcontroller and a test application implemented in LabVIEW running on a PC. The tactile display system is intended to be integrated into the socket of a hand prosthesis and used as a conscious sensory feedback system for hand amputees using a myoelectrically controlled hand prosthesis. The system will provide continuous force feedback from sensors in the fingertips of each prosthetic finger and will likely improve the users' controllability and perception of the prosthetic hand. Here we report on tests made on "a five site" localization discrimination task and three pressure level discrimination tasks on the forearm of five healthy participants (non-amputees) using the LabView application to generate the stimulations. A mean five-finger discrimination accuracy of 86% and a mean three-level pressure discrimination accuracy of 93% were achieved, indicating the system to be a viable method of producing sensory feedback on the level of individual fingers.
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| 7. |
- Antfolk, Christian, et al.
(författare)
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Artificial Redirection of Sensation From Prosthetic Fingers to the Phantom Hand Map on Transradial Amputees: Vibrotactile Versus Mechanotactile Sensory Feedback
- 2013
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Ingår i: IEEE Transactions on Neural Systems and Rehabilitation Engineering. - 1534-4320. ; 21:1, s. 112-120
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Tidskriftsartikel (refereegranskat)abstract
- This work assesses the ability of transradial amputees to discriminate multi-site tactile stimuli in sensory discrimination tasks. It compares different sensory feedback modalities using an artificial hand prosthesis in: 1) a modality matched paradigm where pressure recorded on the five fingertips of the hand was fed back as pressure stimulation on five target points on the residual limb; and 2) a modality mismatched paradigm where the pressures were transformed into mechanical vibrations and fed back. Eight transradial amputees took part in the study and were divided in two groups based on the integrity of their phantom map; group A had a complete phantom map on the residual limb whereas group B had an incomplete or nonexisting map. The ability in localizing stimuli was compared with that of 10 healthy subjects using the vibration feedback and 11 healthy subjects using the pressure feedback (in a previous study), on their forearms, in similar experiments. Results demonstrate that pressure stimulation surpassed vibrotactile stimulation in multi-site sensory feedback discrimination. Furthermore, we demonstrate that subjects with a detailed phantom map had the best discrimination performance and even surpassed healthy participants for both feedback paradigms whereas group B had the worst performance overall. Finally, we show that placement of feedback devices on a complete phantom map improves multi-site sensory feedback discrimination, independently of the feedback modality.
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| 8. |
- Antfolk, Christian, et al.
(författare)
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Design and technical construction of a tactile display for sensory feedback in a hand prosthesis system
- 2010
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Ingår i: BioMedical Engineering Online. - 1475-925X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background: The users of today's commercial prosthetic hands are not given any conscious sensory feedback. To overcome this deficiency in prosthetic hands we have recently proposed a sensory feedback system utilising a "tactile display" on the remaining amputation residual limb acting as man-machine interface. Our system uses the recorded pressure in a hand prosthesis and feeds back this pressure onto the forearm skin. Here we describe the design and technical solution of the sensory feedback system aimed at hand prostheses for trans-radial/humeral amputees. Critical parameters for the sensory feedback system were investigated. Methods: A sensory feedback system consisting of five actuators, control electronics and a test application running on a computer has been designed and built. Firstly, we investigate which force levels were applied to the forearm skin of the user while operating the sensory feedback system. Secondly, we study if the proposed system could be used together with a myoelectric control system. The displacement of the skin caused by the sensory feedback system would generate artefacts in the recorded myoelectric signals. Accordingly, EMG recordings were performed and an analysis of the these are included. The sensory feedback system was also preliminarily evaluated in a laboratory setting on two healthy non-amputated test subjects with a computer generating the stimuli, with regards to spatial resolution and force discrimination. Results: We showed that the sensory feedback system generated approximately proportional force to the angle of control. The system can be used together with a myoelectric system as the artefacts, generated by the actuators, were easily removed using a simple filter. Furthermore, the application of the system on two test subjects showed that they were able to discriminate tactile sensation with regards to spatial resolution and level of force. Conclusions: The results of these initial experiments in non-amputees indicate that the proposed tactile display, in its simple form, can be used to relocate tactile input from an artificial hand to the forearm and that the system can coexist with a myoelectric control systems. The proposed system may be a valuable addition to users of myoelectric prosthesis providing conscious sensory feedback during manipulation of objects.
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| 9. |
- Antfolk, Christian, et al.
(författare)
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SmartHand tactile display: A new concept for providing sensory feedback in hand prostheses.
- 2010
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Medical Journals Sweden AB. - 1651-2073. ; 44, s. 50-53
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Tidskriftsartikel (refereegranskat)abstract
- Abstract A major drawback with myoelectric prostheses is that they do not provide the user with sensory feedback. Using a new principle for sensory feedback, we did a series of experiments involving 11 healthy subjects. The skin on the volar aspect of the forearm was used as the target area for sensory input. Experiments included discrimination of site of stimuli and pressure levels at a single stimulation point. A tactile display based on digital servomotors with one actuating element for each of the five fingers was used as a stimulator on the forearm. The results show that the participants were able to discriminate between three fingers with an accuracy of 97%, between five fingers with an accuracy of 82%, and between five levels with an accuracy of 79%. The tactile display may prove a helpful tool in providing amputees with sensory feedback from a prosthetic hand by transferring tactile stimuli from the prosthetic hand to the skin at forearm level.
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| 10. |
- Antfolk, Christian, et al.
(författare)
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Using EMG for Real-time Prediction of Joint Angles to Control a Prosthetic Hand Equipped with a Sensory Feedback System
- 2010
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Ingår i: Journal of Medical and Biological Engineering. - : Taiwanese Society of Biomedical Engineering. - 1609-0985. ; 30:6, s. 399-405
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Tidskriftsartikel (refereegranskat)abstract
- All commercially available upper limb prosthesis controllers only allow the hand to be commanded in an open and close fashion without any sensory feedback to the user. Here the evaluation of a multi-degree of freedom hand controlled using a real-time EMG pattern recognition algorithm and incorporating a sensory feedback system is reported. The hand prosthesis, called SmartHand, was controlled in real-time by using 16 myoelectric signals from the residual limb of a 25-year old male transradial amputee in a two day long evaluation session. Initial training of the EMG pattern recognition algorithm was performed with a dataglove fitted to the contralateral hand recording joint angle positions of the fingers and mapping joint angles of the fingers to the EMG data. In the following evaluation sessions, the myoelectric signals were classified using local approximation and lazy learning, producing finger joint angle outputs and consequently controlling the prosthetic hand. Sensory information recorded from force sensors in the artificial hand was relayed to actuators, integrated in the socket of the prosthesis, continuously delivering force sensory feedback stimulations to the stump of the amputee. The participant was able to perform several dextrous movements as well as functional grip tasks after only two hours of training and increased his controllability during the two day session. In the final evaluation session a mean classification accuracy of 86% was achieved.
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