A BIONIC HAND VS. A REPLANTED HAND.

Objective: Evaluation of the hand function affected when replacing a malfunctioning hand by a bionic hand. Design: Case report. Subjects: One individual that wished for a better quality of life after unsatisfying hand function following a replantation. Methods: A quantitative and qualitative evaluation of body functions as well as activity performance and participation before and after a planned amputation and prosthetic fitting is presented. Results: Improvements were seen in the patient-reported outcome measures (PROMs) that were used regarding activity (Disability of the Arm, Shoulder and Hand [DASH] and Canadian Occupational Performance Measure [COPM]), pain (Neuropathic Pain Symptom Inventory [NPSI], Brief Pain Inventory [BPI], Visual Analogue Scale [VAS]), cold intolerance (CISS) and health related quality of life (SF-36), as well as in the standardised grip function test, Southampton Hand Assessment Procedure (SHAP). No referred sensations were seen but the discriminative touch on the forearm was improved. In the qualitative interview, a relief of pain, a lack of cold intolerance, improved appearance, better grip function and overall emotional wellbeing were expressed. Conclusions: The planned amputation and subsequent fitting and usage of a hand prosthesis were satisfying for the individual with positive effects on activity and participation. Clinical relevance: When the hand function after a hand replantation does not reach satisfactory levels, a planned amputation and a prosthetic hand can be the right solution.

Experiences of SENSory Relearning of the UPPer Limb (SENSUPP) after Stroke and Perceived Effects: A Qualitative Study.

Recently, it was shown that sensory relearning of the upper limb (SENSUPP) is a promising intervention to improve sensorimotor function after stroke. There is limited knowledge, however, of how participants perceive the training. Here, we explored how persons with sensory impairments in the upper limb experienced the SENSUPP protocol (combined sensory- and motor training and home exercises for 5 weeks) and its effect. Fifteen persons (mean age 59 years; 10 men; >6 months post-stroke) were individually interviewed, and data were analyzed with qualitative content analysis. An overall theme 'Sensory relearning was meaningful and led to improved ability to perform daily hand activities' and two categories with six subcategories emerged. The outpatient training was perceived as meaningful, although the exercises were demanding and required concentration. Support from the therapist was helpful and training in small groups appreciated. The home training was challenging due to lack of support, time, and motivation. Small improvements in sensory function were perceived, whereas increased movement control and ability in performing daily hand activities were reported. In conclusion, the SENSUPP protocol is meaningful and beneficial in improving the functioning of the UL in chronic stroke. Improving compliance to the home training, regular follow-ups, and an exercise diary are recommended.

Efficacy and feasibility of SENSory relearning of the UPPer limb (SENSUPP) in people with chronic stroke: A pilot randomized controlled trial.

BACKGROUND: Sensorimotor impairments of the upper limb (UL) are common after stroke, but there is a lack of evidence-based interventions to improve functioning of UL. OBJECTIVE: To evaluate (1) the efficacy of sensory relearning and task-specific training compared to task-specific training only, and (2) the feasibility of the training in chronic stroke. DESIGN: A pilot randomized controlled trial. SETTING: University hospital outpatient clinic. PARTICIPANTS: Twenty-seven participants (median age; 62 years, 20 men) were randomized to an intervention group (IG; n = 15) or to a control group (CG; n = 12). INTERVENTION: Both groups received training twice weekly in 2.5-hour sessions for 5 weeks. The training in the IG consisted of sensory relearning, task-specific training, and home training. The training in the CG consisted of task-specific training. MAIN OUTCOME MEASURES: Primary outcome was sensory function (touch thresholds, touch discrimination, light touch, and proprioception). Secondary outcomes were dexterity, ability to use the hand in daily activities, and perceived participation. A blinded assessor conducted the assessments at baseline (T1), post intervention (T2), and at 3-month follow-up (T3). Nonparametric analyses and effect-size calculations (r) were performed. Feasibility was evaluated by a questionnaire. RESULTS: After the training, only touch thresholds improved significantly from T1 to T2 (p = .007, r = 0.61) in the IG compared to the CG. Within the IG, significant improvements were found from T1 to T2 regarding use of the hand in daily activities (p = .001, r = 0.96) and movement quality (p = .004, r = 0.85) and from T1 to T3 regarding satisfaction with performance in meaningful activities (p = .004, r = 0.94). The CG significantly improved the performance of using the hand in meaningful activities from T1 to T2 (p = .017, r = 0.86). The training was well tolerated by the participants and performed without any adverse events. CONCLUSIONS: Combined sensory relearning and task-specific training may be a promising and feasible intervention to improve UL sensorimotor function after stroke.

SENSory re-learning of the UPPer limb (SENSUPP) after stroke: development and description of a novel intervention using the TIDieR checklist.

BACKGROUND: Sensorimotor impairments of upper limb (UL) are common after stroke, leading to difficulty to use the UL in daily life. Even though many have sensory impairments in the UL, specific sensory training is often lacking in stroke rehabilitation. Thus, the aim of this paper is to provide a detailed description of the novel intervention "SENSory re-learning of the UPPer limb after stroke (SENSUPP)" that we have developed to improve functioning in the UL in persons with mild to moderate impairments after stroke. METHODS: The SENSUPP protocol was designed using information from literature reviews, clinical experience and through consultation of experts in the field. The protocol integrates learning principles based on current neurobiological knowledge and includes repetitive intensive practice, difficulty graded exercises, attentive exploration of a stimulus with focus on the sensory component, and task-specific training in meaningful activities that includes feedback. For reporting the SENSUPP protocol, the Template for Intervention Description and Replication (TIDieR) checklist was used. RESULTS: The essential features of the SENSUPP intervention comprise four components: applying learning principles based on current neurobiological knowledge, sensory re-learning (exercises for touch discrimination, proprioception and tactile object recognition), task-specific training in meaningful activities, and home-training. The training is performed twice a week, in 2.5-h sessions for 5 weeks. CONCLUSION: Since there is close interaction between the sensory and motor systems, the SENSUPP intervention may be a promising method to improve UL functioning after stroke. The TIDieR checklist has been very useful for reporting the procedure and development of the training. TRIAL REGISTRATION: ClinicalTrials.gov NCT03336749 . Registered on 8 November 2017.

Sensory Feedback in Hand Prostheses: A Prospective Study of Everyday Use.

INTRODUCTION: Sensory feedback in hand prostheses is lacking but wished for. Many amputees experience a phantom hand map on their residual forearm. When the phantom hand map is touched, it is experienced as touch on the amputated hand. A non-invasive sensory feedback system, applicable to existing hand prostheses, can transfer somatotopical sensory information via phantom hand map. The aim was to evaluate how forearm amputees experienced a non-invasive sensory feedback system used in daily life over a 4-week period. METHODS: This longitudinal cohort study included seven forearm amputees. A non-invasive sensory feedback system was used over 4 weeks. For analysis, a mixed method was used, including quantitative tests (ACMC, proprioceptive pointing task, questionnaire) and interviews. A directed content analysis with predefined categories sensory feedback from the prosthesis, agency, body ownership, performance in activity, and suggestions for improvements was applied. RESULTS: The results from interviews showed that sensory feedback was experienced as a feeling of touch which contributed to an experience of completeness. However, the results from the questionnaire showed that the sense of agency and performance remained unchanged or deteriorated. The ability to feel and manipulate small objects was difficult and a stronger feedback was wished for. Phantom pain was alleviated in four out of five patients. CONCLUSION: This is the first time a non-invasive sensory feedback system for hand prostheses was implemented in the home environment. The qualitative and quantitative results diverged. The sensory feedback was experienced as a feeling of touch which contributed to a feeling of completeness, linked to body ownership. The qualitative result was not verified in the quantitative measurements. CLINICAL TRIAL REGISTRATION: Name: Evaluation of a Non-invasive Sensory Feedback System in Hand Prostheses. Date of registration: March 15, 2019. Date the first participant was enrolled: April 1, 2015. ClinicalTrials.gov Identifier: NCT03876405 ORCID ID: https://orcid.org/0000-0002-4140-7478.

Touch on predefined areas on the forearm can be associated with specific fingers: Towards a new principle for sensory feedback in hand prostheses.

OBJECTIVE: Currently available hand prostheses lack sensory feedback. A "phantom hand map", a referred sensation, on the skin of the residual arm is a possible target to provide amputees with non-invasive somatotopically matched sensory feedback. How-ever, not all amputees experience a phantom hand map. The aim of this study was to explore whether touch on predefined areas on the forearm can be associated with specific fingers. DESIGN: A longitudinal cohort study. SUBJECTS: A total of 31 able-bodied individuals. METHODS: A "tactile display" was developed consisting of 5 servo motors, which provided the user with mechanotactile stimulus. Predefined pressure points on the volar aspect of the forearm were stimulated during a 2-week structured training period. RESULTS: Agreement between the stimulated areas and the subjects' ability to discriminate the stimulation was high, with a distinct improvement up to the third training occasion, after which the kappa score stabilized for the rest of the period. CONCLUSION: It is possible to associate touch on intact skin on the forearm with specific fingers after a structured training period, and the effect persisted after 2 weeks. These results may be of importance for the development of non-invasive sensory feedback systems in hand prostheses.

Shape-texture-identification-STI-A test for tactile gnosis: Concurrent validity of STI2.

STUDY DESIGN: Cross-sectional study. INTRODUCTION: The shape-texture-identification (STI) test (Össur Nordic AB, Sweden) is used to evaluate one aspect of tactile gnosis in nerve disorders, and it has proven good methodological properties. PURPOSE OF THE STUDY: A new version of the STI test was recently introduced-STI2 (www.sensory-test.com). The purpose of this study was to test the concurrent validity in STI2. METHODS: Using a cross-sectional design, this methodological study compared STI2 to the original version based on 2 cohorts; 1 including 20 persons (1 affected finger and corresponding finger on in opposite hand) with affected sensibility after hand injuries and 1 healthy group including 20 persons (digits II and V in both hands). The agreement between the 2 versions of the instrument was calculated statistically by a percentage comparison of the test results and weighted kappa. RESULTS: The 112 tested fingers showed a complete agreement, or 1-point accepted deviation, between the 2 tests in 92% with weighted kappa of 0.74 and 95% confidence interval of 0.63-0.89. The result showed that there is no significant deviation between the 2 versions of the test. DISCUSSION: The use of standardizes and evidence based assessment tools in clinical practice is paramount for a patient centered healthcare. Previous research has shown good psychometric proprties in the STI-test. This study contributes to the scientific evidence of the instrument. CONCLUSION: As the new STI2 proved good agreement within the accepted deviation, we conclude that there is evidence to use the new STI2 test in assessment of tactile gnosis.

Atypical sensory processing pattern following median or ulnar nerve injury - a case-control study.

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.

SENSory re-learning of the UPPer limb after stroke (SENSUPP): study protocol for a pilot randomized controlled trial.

BACKGROUND: Many stroke survivors suffer from sensory impairments of their affected upper limb (UL). Although such impairments can affect the ability to use the UL in everyday activities, very little attention is paid to sensory impairments in stroke rehabilitation. The purpose of this trial is to investigate if sensory re-learning in combination with task-specific training may prove to be more effective than task-specific training alone to improve sensory function of the hand, dexterity, the ability to use the hand in daily activities, perceived participation, and life satisfaction. METHODS/DESIGN: This study is a single-blinded pilot randomized controlled trial (RCT) with two treatment arms. The participants will be randomly assigned either to sensory re-learning in combination with task-specific training (sensory group) or to task-specific training only (control group). The training will consist of 2.5 h of group training per session, 2 times per week for 5 weeks. The primary outcome measures to assess sensory function are as follows: Semmes-Weinstein monofilament, Shape/Texture Identification (STI™) test, Fugl-Meyer Assessment-upper extremity (FMA-UE; sensory section), and tactile object identification test. The secondary outcome measures to assess motor function are as follows: Box and Block Test (BBT), mini Sollerman Hand Function Test (mSHFT), Modified Motor Assessment Scale (M-MAS), and Grippit. To assess the ability to use the hand in daily activities, perceived participation, and life satisfaction, the Motor Activity Log (MAL), Canadian Occupational Performance Measure (COPM), Stroke Impact Scale (SIS) participation domain, and Life Satisfaction checklist will be used. Assessments will be performed pre- and post-training and at 3-month follow-up by independent assessors, who are blinded to the participants' group allocation. At the 3-month follow-up, the participants in the sensory group will also be interviewed about their general experience of the training and how effective they perceived the training. DISCUSSION: The results from this study can add new knowledge about the effectiveness of sensory re-learning in combination with task-specific training on UL functioning after stroke. If the new training approach proves efficient, the results can provide information on how to design a larger RCT in the future in persons with sensory impairments of the UL after stroke. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03336749 . Registered on 8 November 2017.

The effect of early relearning on sensory recovery 4 to 9 years after nerve repair: a report of a randomized controlled study.

Twenty patients randomized to early sensory relearning (nine patients) or traditional relearning (11 patients) were assessed regarding sensory recovery 4 to 9 years after median or ulnar nerve repair. Outcomes were assessed with the Rosen score, questionnaires, and self-reported single-item questions regarding function and activity. The patients with early sensory relearning had significantly better sensory recovery in the sensory domain of the Rosen score, specifically, discriminative touch or tactile gnosis and dexterity. They had significantly less self-reported problems in gripping, clumsiness, and fine motor skills. No differences were found in questionnaires between the two groups. We conclude that early sensory relearning improves long-term sensory recovery following nerve repair. LEVEL OF EVIDENCE: I.

Patients' views on early sensory relearning following nerve repair-a Q-methodology study.

STUDY DESIGN: Descriptive study. INTRODUCTION: Early sensory relearning where the dynamic capacity of the brain is used has been shown to improve sensory outcome after nerve repair. However, no previous studies have examined how patients experience early sensory relearning. PURPOSE OF THE STUDY: To describe patient's views on early sensory relearning. METHODS: Statements' scores were analyzed by factor analysis. RESULTS: Thirty-seven consecutive adult patients with median and/or ulnar nerve repair who completed early sensory relearning were included. Three factors were identified, explaining 45% of the variance: (1) "Believe sensory relearning is meaningful, manage to get an illusion of touch and complete the sensory relearning"; (2) "Do not get an illusion of touch easily and need support in their sensory relearning" (3) "Are not motivated, manage to get an illusion of touch but do not complete sensory relearning". DISCUSSION: Many patients succeed in implementing their sensory relearning. However, a substantial part of the patient population need more support, have difficulties to create illusion of touch, and lack motivation to complete the sensory relearning. To enhance motivation and meaningfulness by relating the training clearly to everyday occupations and to the patient's life situation is a suggested way to proceed. CONCLUSION: The three unique factors indicate motivation and sense of meaningfulness as key components which should be taken into consideration in developing programs for person-centered early sensory relearning. LEVEL OF EVIDENCE: 3.

Vibration thresholds in carpal tunnel syndrome assessed by multiple frequency vibrometry: a case-control study.

BACKGROUND: Carpal tunnel syndrome (CTS) is the most common compression neuropathy, but there is no gold standard for establishing the diagnosis. The ability to feel vibrations in the fingertips is dependent on the function in cutaneous receptors and afferent nerves. Our aim was to investigate vibration perception thresholds (VPTs) in patients with CTS using multi-frequency vibrometry. METHODS: Sixty-six patients (16 men and 50 women) with CTS, diagnosed from clinical signs and by electroneurography, and 66 matched healthy controls were investigated with multi-frequency vibrometry. The VPTs were assessed at seven frequencies (8, 16, 32, 64, 125, 250, and 500 Hz) in the index finger and little finger bilaterally. The severity of the CTS was graded according to Padua and the patient's subjective symptoms were graded according to the Boston carpal tunnel questionnaire. Touch thresholds were assessed using the Semmes-Weinstein monofilaments. RESULTS: Patients with CTS had significantly higher VPTs at all frequencies in the index finger and in 6 out of 7 frequencies in the little finger compared to the controls. However, the VPT was not worse in patients with more severe CTS. Patients with unilateral CTS showed significantly higher VPTs in the affected hand. There were no correlations between VPTs and electrophysiological parameters, subjective symptoms, or touch threshold. CONCLUSIONS: Patients with CTS had impaired VPTs at all frequencies compared to the controls. Since the VPTs are dependent on function in peripheral receptors and their afferent nerves, multi-frequency vibrometry could possibly lead to diagnosis of CTS.

Sensation, mechanoreceptor, and nerve fiber function after nerve regeneration.

OBJECTIVE: Sensation is essential for recovery after peripheral nerve injury. However, the relationship between sensory modalities and function of regenerated fibers is uncertain. We have investigated the relationships between touch threshold, tactile gnosis, and mechanoreceptor and sensory fiber function after nerve regeneration. METHODS: Twenty-one median or ulnar nerve lesions were repaired by a collagen nerve conduit or direct suture. Quantitative sensory hand function and sensory conduction studies by near-nerve technique, including tactile stimulation of mechanoreceptors, were followed for 2 years, and results were compared to noninjured hands. RESULTS: At both repair methods, touch thresholds at the finger tips recovered to 81 ± 3% and tactile gnosis only to 20 ± 4% (p < 0.001) of control. The sensory nerve action potentials (SNAPs) remained dispersed and areas recovered to 23 ± 2% and the amplitudes only to 7 ± 1% (P < 0.001). The areas of SNAPs after tactile stimulation recovered to 61 ± 11% and remained slowed. Touch sensation correlated with SNAP areas (p < 0.005) and was negatively related to the prolongation of tactile latencies (p < 0.01); tactile gnosis was not related to electrophysiological parameters. INTERPRETATION: The recovered function of regenerated peripheral nerve fibers and reinnervated mechanoreceptors may differentially influence recovery of sensory modalities. Touch was affected by the number and function of regenerated fibers and mechanoreceptors. In contrast, tactile gnosis depends on the input and plasticity of the central nervous system (CNS), which may explain the absence of a direct relation between electrophysiological parameters and poor recovery. Dispersed maturation of sensory nerve fibers with desynchronized inputs to the CNS also contributes to the poor recovery of tactile gnosis. Ann Neurol 2017. Ann Neurol 2017;82:940-950.

Carpal tunnel syndrome treated with guided brain plasticity: a randomised, controlled study.

INTRODUCTION: Guided plasticity, induced by cutaneous forearm anaesthesia, improves hand sensibility in patients with nerve injury and vibration-induced neuropathy. This study investigated whether patients with carpal tunnel syndrome (CTS) would benefit from cutaneous forearm anaesthesia. METHODS: Seventy patients with clinical and electroneurography-verified CTS were randomised to sensory training combined with either an anaesthetic cream (EMLA®) (n = 34) or a placebo cream (n = 36) on the volar part of the forearm. The treatment was repeated at increasing intervals over 8 weeks. The primary outcome was the Boston carpal tunnel questionnaire (BCTQ) symptom severity scale after 8 weeks. Secondary outcomes included activity limitations, sensory function, and nerve conduction. This study compared the longitudinal changes between the two groups, and with correction for multiple comparisons it also compared the longitudinal change within the groups. RESULTS: There were no significant differences in primary or secondary outcomes between the groups. However, the BCTQ symptom severity scale improved significantly within the EMLA® group over the 8-week period (p = 0.001). Apart from this, no significant improvements in activity limitations, sensory function, or nerve conduction were seen in the two groups compared to baseline. Altogether, 47% of patients in the EMLA® group and 61% in the placebo group had been operated on with carpal tunnel release by 12 months. CONCLUSION: An 8-week treatment protocol with cutaneous forearm anaesthesia to guide brain plasticity gave no significant subjective or objective improvements in hand function compared to placebo.

Sensory qualities of the phantom hand map in the residual forearm of amputees.

OBJECTIVE: Most amputees experience referred sensations, known as a phantom hand map, on the residual forearm, where touch on specific areas is perceived as touch on the amputated hand. The aim of this study was to evaluate the sensory qualities of the phantom hand map. METHODS: In 10 traumatic forearm-amputees touch thres-holds and discriminative touch of the phantom hand map were assessed and compared with corresponding areas on the contralateral forearm. The study assessed the localization of touch on the phantom hand map, and how distinct and similar to normal touch the referred feeling was. RESULTS: Similar touch thresholds were seen in the phantom hand map and the control site. Tactile discrimination, requiring both detection of stimulus and interpretation, was significantly better in the phantom hand map. CONCLUSION: This explorative study suggests that the phantom hand map and the superior tactile discrimination seen in the phantom hand map are based on adaptations within the brain. Further studies investigating the neural basis for the phantom hand map are needed.

Early sensory re-education of the hand after peripheral nerve repair based on mirror therapy: a randomized controlled trial

BACKGROUND: Mirror therapy has been used as an alternative stimulus to feed the somatosensory cortex in an attempt to preserve hand cortical representation with better functional results. OBJECTIVE: To analyze the short-term functional outcome of an early re-education program using mirror therapy compared to a late classic sensory program for hand nerve repair. METHOD: This is a randomized controlled trial. We assessed 20 patients with median and ulnar nerve and flexor tendon repair using the Rosen Score combined with the DASH questionnaire. The early phase group using mirror therapy began on the first postoperative week and lasted 5 months. The control group received classic sensory re-education when the protective sensation threshold was restored. All participants received a patient education booklet and were submitted to the modified Duran protocol for flexor tendon repair. The assessments were performed by the same investigator blinded to the allocated treatment. Mann-Whitney Test and Effect Size using Cohen's d score were used for inter-group comparisons at 3 and 6 months after intervention. RESULTS: The primary outcome (Rosen score) values for the Mirror Therapy group and classic therapy control group after 3 and 6 months were 1.68 (SD=0.5); 1.96 (SD=0.56) and 1.65 (SD=0.52); 1.51 (SD=0.62), respectively. No between-group differences were observed. CONCLUSION: Although some clinical improvement was observed, mirror therapy was not shown to be more effective than late sensory re-education in an intermediate phase of nerve repair in the hand. Replication is needed to confirm these findings.

Early sensory re-education of the hand after peripheral nerve repair based on mirror therapy: a randomized controlled trial.

BACKGROUND: Mirror therapy has been used as an alternative stimulus to feed the somatosensory cortex in an attempt to preserve hand cortical representation with better functional results. OBJECTIVE: To analyze the short-term functional outcome of an early re-education program using mirror therapy compared to a late classic sensory program for hand nerve repair. METHOD: This is a randomized controlled trial. We assessed 20 patients with median and ulnar nerve and flexor tendon repair using the Rosen Score combined with the DASH questionnaire. The early phase group using mirror therapy began on the first postoperative week and lasted 5 months. The control group received classic sensory re-education when the protective sensation threshold was restored. All participants received a patient education booklet and were submitted to the modified Duran protocol for flexor tendon repair. The assessments were performed by the same investigator blinded to the allocated treatment. Mann-Whitney Test and Effect Size using Cohen's d score were used for inter-group comparisons at 3 and 6 months after intervention. RESULTS: The primary outcome (Rosen score) values for the Mirror Therapy group and classic therapy control group after 3 and 6 months were 1.68 (SD=0.5); 1.96 (SD=0.56) and 1.65 (SD=0.52); 1.51 (SD=0.62), respectively. No between-group differences were observed. CONCLUSION: Although some clinical improvement was observed, mirror therapy was not shown to be more effective than late sensory re-education in an intermediate phase of nerve repair in the hand. Replication is needed to confirm these findings.

Normalized activation in the somatosensory cortex 30 years following nerve repair in children: an fMRI study.

The clinical outcome following a peripheral nerve injury in the upper extremity is generally better in young children than in teenagers and in adults, but the mechanism behind this difference is unknown. In 28 patients with a complete median nerve injury sustained at the ages of 1-13 years (n = 13) and 14-20 years (n = 15), the cortical activation during tactile finger stimulation of the injured and healthy hands was monitored at a median time since injury of 28 years using functional magnetic resonance imaging (fMRI) at 3 Tesla. The results from the fMRI were compared with the clinical outcome and electroneurography. The cortical activation pattern following sensory stimulation of the median nerve-innervated fingers was dependent on the patient's age at injury. Those injured at a young age (1-13 years) had an activation pattern similar to that of healthy controls. Furthermore, they showed a clinical outcome significantly superior (P = 0.001) to the outcome in subjects injured at a later age; however, electroneurographical parameters did not differ between the groups. In subjects injured at age 14-20 years, a more extended activation of the contralateral hemisphere was seen in general. Interestingly, these patients also displayed changes in the ipsilateral hemisphere where a reduced inhibition of somatosensory areas was seen. This loss of ipsilateral inhibition correlated to increasing age at injury as well as to poor recovery of sensory functions in the hand. In conclusion, cerebral changes in both brain hemispheres may explain differences in clinical outcome following a median nerve injury in childhood or adolescence.

Collagen conduit versus microsurgical neurorrhaphy: 2-year follow-up of a prospective, blinded clinical and electrophysiological multicenter randomized, controlled trial.

PURPOSE: To compare repair of acute lacerations of mixed sensory-motor nerves in humans using a collagen tube versus conventional repair. METHODS: In a prospective randomized trial, we repaired the ulnar or the median nerve with a collagen nerve conduit or with conventional microsurgical techniques. We enrolled 43 patients with 44 nerve lacerations. We performed electrophysiological tests and hand function using a standardized clinical evaluation instrument, the Rosen scoring system, after 12 and 24 months. RESULTS: Operation time using the collagen conduit was significantly shorter than for conventional neurorrhaphy. There were no complications in terms of infection, extrusion of the conduit, or other local adverse reaction. Thirty-one patients with 32 nerve lesions, repaired with collagen conduits or direct suture, attended the 24-month follow-up. There was no difference between sensory function, discomfort, or total Rosen scores. Motor scores were significantly better for the direct suture group after 12 months, but after 24 months, there were no differences between the treatment groups. There was a general further recovery of both motor and sensory conduction parameters at 24 months compared with 12 months. There were no statistically significant differences in amplitudes, latencies, or conduction velocities between the groups. CONCLUSIONS: Use of a collagen conduit produced recovery of sensory and motor functions that were equivalent to direct suture 24 months after repair when the nerve gap inside the tube was 6 mm or less, and the collagen conduit proved to be safe for these nerve lacerations in the forearm. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Sensory feedback in upper limb prosthetics.

One of the challenges facing prosthetic designers and engineers is to restore the missing sensory function inherit to hand amputation. Several different techniques can be employed to provide amputees with sensory feedback: sensory substitution methods where the recorded stimulus is not only transferred to the amputee, but also translated to a different modality (modality-matched feedback), which transfers the stimulus without translation and direct neural stimulation, which interacts directly with peripheral afferent nerves. This paper presents an overview of the principal works and devices employed to provide upper limb amputees with sensory feedback. The focus is on sensory substitution and modality matched feedback; the principal features, advantages and disadvantages of the different methods are presented.