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Biomedical subjects

B Rosén

Publications and source records attributed to B Rosén.

At least 19 recordsLinked to original sources
PubMed2006

Enhanced sensory recovery after median nerve repair using cortical audio-tactile interaction. A randomised multicentre study.

The "Sensor Glove System" offers an alternate afferent inflow from the hand early after nerve repair in the forearm, mediated through the hearing sense, implying that deprivation of one sense can be compensated by another sense. This sensory "by-pass" was used early after repair of the median nerve with the intention of improving recovery of functional sensibility by maintaining an active sensory map of the hand in the somatosensory cortex during the deafferentation period. In a prospective multicentre clinical study, one group (n=14) started early after surgery with sensory re-education using the Sensor Glove System and the control group (n=12) received conventional sensory re-education, starting 3 months postoperatively. The patients were checked regularly during a 1-year period, with focus on recovery of tactile gnosis. After 12, months, tactile gnosis was significantly better in the Sensor Glove System group. This highlights the timing for introduction of training after nerve repair, focusing on the importance of immediate sensory re-learning.

Acoustic Stimulation↗
PubMed2006

The reliability and validity of the locognosia test after injuries to peripheral nerves in the hand.

Locognosia, the ability to localise touch, is one aspect of tactile spatial discrimination which relies on the integrity of peripheral end-organs as well as the somatosensory representation of the surface of the body in the brain. The test presented here is a standardised assessment which uses a protocol for testing locognosia in the zones of the hand supplied by the median and/or ulnar nerves. The test-retest reliability and discriminant validity were investigated in 39 patients with injuries to the median or ulnar nerve. Intraclass correlation coefficients were used to calculate the test-retest reliability. Discriminant validity was assessed by comparing the injured with the unaffected hand. Excellent test-retest reliability was demonstrated for the injuries to the median (intraclass correlation coefficient 0.924, 95% confidence interval 0.848 to 1.00) and the ulnar nerves (intraclass correlation coefficient 0.859, 95% confidence interval 0.693 to 1.00). The magnitude of the difference in scores between affected and unaffected hands showed good discriminant validity. For injuries to the median nerve the mean difference was 11.1 points (1 to 33; SD 7.4), which was statistically significant (p < 0.0001, paired t-test) and for those of the ulnar nerve it was 4.75 points (1 to 13.5; SD 3.16), which was also statistically significant (paired t-test, p < 0.0001). The locognosia test has excellent test-retest reliability, is a valid test of tactile spatial discrimination and should be included in the evaluation of outcome after injury to peripheral nerves.

Adolescent↗
PubMed2005

Improved sensory relearning after nerve repair induced by selective temporary anaesthesia - a new concept in hand rehabilitation.

The outcome after nerve repair in adults is generally poor. We hypothesized that forearm deafferentation would enhance the sensory outcome by increasing the cortical hand representation. A prospective, randomized, double-blind study was designed to investigate the effects of cutaneous forearm anaesthesia combined with sensory re-education on the outcome after ulnar or median nerve repair. During a 2 week period, a local anaesthetic cream (EMLA (n = 7) or placebo (n=6) was applied repeatedly onto the flexor aspect of the forearm of the injured arm and combined with sensory re-education. Evaluation of sensory function was carried out at regular intervals and at 4 weeks after the last EMLA/placebo session. The EMLA group showed significant improvement compared to placebo in perception of touch/pressure, tactile gnosis and in the summarized outcome after 6 weeks. These results suggest that cutaneous forearm anaesthesia of the injured limb, in combination with sensory re-education, can enhance sensory recovery after nerve repair.

Adult↗
PubMed2004

Tubular repair of the median or ulnar nerve in the human forearm: a 5-year follow-up.

The long-term outcome from silicone tube nerve repair was compared with the outcome from routine microsurgical repair in a clinical randomized prospective study, comprising 30 patients with median or ulnar nerve injuries in the distal forearm. Postoperatively, the patients underwent neurophysiological and clinical assessments of sensory and motor function regularly over a 5-year period. After 5 years there was no significant difference in outcome between the two techniques except that cold intolerance was significantly less severe with the tubular technique. In the total group there was ongoing improvement of functional sensibility throughout the 5 years after repair. It is concluded that tubular repair of the median and ulnar nerves is at least as good as routine microsurgical repair, and results in less cold intolerance.

Adolescent↗
PubMed2004

The two-point discrimination test--time for a re-appraisal?

The two-point discrimination (2PD) test is the most frequently used test for the assessment of the sensory outcome after nerve repair. Here we focus on factors which explain the enormous and implausible variability in reported 2PD levels after nerve repair. We conclude that the 2PD testing technique is not at all standardized and that its use as the sole test for tactile gnosis recovery should be seriously questioned. Reports of 2PD results should always be accompanied by a detailed description of how the test was performed, especially with reference to the pressure applied and the testing protocol.

Discrimination Learning↗
PubMed2004

Sensory re-education after nerve repair: aspects of timing.

The recovery of functional sensibility after nerve transection and repair is often disappointing. Here we address the timing of sensory re-education that aims at re-learning and modulating the changed sensory code from the hand after such an injury. Such training utilises the capacity for cortical functional re-modelling which characterises the young as well as the adult brain. Sensory re-education is traditionally not introduced until there is reinnervation in the hand, and such a late onset of training may be one explanatory factor for the poor functional results after nerve repair. Since functional reorganisation changes of the cortex occurring after changes in peripheral input are very fast processes, we suggest that this specific intervention should be introduced very early in the rehabilitation phase--already in the initial phase after nerve repair when no axons have yet arrived to the asensible hand. The goal is to avoid, minimise and modulate the central functional re-organisation which follows the de-afferentiation associated with nerve injury and repair. This early intervention can be done with the use of artificial sensibility the first post-operative day. According to this technique, based on sense substitution and utilising the multimodal capacity of the brain, miniature microphones on the fingertips of the asensible hand pick up the friction sound generated by active touch. The vibro-tactile signals are stereophonically transposed to vibro-acoustic signals, thereby providing an alternate feed-back which hypothetically helps to maintain or re-establish the cortical hand map.

Acoustic Stimulation↗
PubMed2002

Hand-arm-vibration syndrome (HAVS): is there a central nervous component? An fMRI study.

Hand-held vibrating tools may result in neuromuscular dysfunction and vasospastic problems of the hand. Sensory and motor dysfunction can be explained by injury to peripheral structures, but could also be due to changes in cortical somatotopic mapping of the hand in the brain. The purpose of the present study was to use functional magnetic resonance imaging (fMRI) to assess the somatotopic cortical representation of the hands of workers subjected to occupational vibration. The study included six men with severe vibration exposures who were suffering from hand-arm-vibration syndrome (HAVS) and six controls. The analysis focused on the pattern and degree of activation of contra- and ipsilateral hemispheres of the brain with tactile stimulation and motor activation of the hand. These stimulations resulted in well-defined activation of the contralateral, and to a lesser extent the ipsilateral hemisphere. Statistical analysis of this limited patient material did not indicate any significant somatotopic cortical changes following long-term exposure to vibrating hand-held tools, although there was a tendency to a shift of activation towards the more cranial parts of the cortex in the patient group.

Adult↗
PubMed2001

Sensory relearning after nerve repair.

One of the challenges in reconstructive surgery is to ensure hand sensibility is regained after median nerve repair. We assessed tactile gnosis in 54 patients (mean age 32 [range 4-72] years) after repair of transected median or ulnar nerves at the wrist level. We found that there is a well-defined critical period for sensory relearning after nerve repair. There is an optimum capacity below age 5-10 years followed by a rapid decline, which levels out after puberty. The curve correlates with previously published data on critical periods for language acquisition among immigrants. Recovery of functional sensibility after nerve repair is based on a learning process and in many ways is analogous to learning a second language.

Adolescent↗
PubMed2001

The long term recovery curve in adults after median or ulnar nerve repair: a reference interval.

This study presents a predicted five-year reference interval for the outcome following repair of the median or ulnar nerve in adults. Forty-four patients were examined with the use of a recently introduced model instrument for documentation after nerve repair that includes "sensory", "motor", and "pain/discomfort" outcomes which together constitute a summarized "total score". Analysis of the "total score" showed that follow-up time and age significantly influence the outcome. There were obvious inferior "motor" results after ulnar nerve injury, but these did not significantly influence the "total score". Significant improvements in the "total score" were seen throughout the follow-up period.

Adolescent↗
PubMed2001

Sensory substitution in prosthetics.

Use of arm and hand prostheses may be essential for many amputees to facilitate activities of daily life and interaction with society. A major drawback that reduces the use of prostheses, however, is the lack of sensibility. Current strategies for sensory feedback in commercially available prostheses are based on force and slip sensors in the mechanical hand for independent grasp control in an opening and closing function. Developing principles for providing conscious sensibility is discussed, including new techniques where hearing is used as substitution for sensation based on sense substitution.

Amputation Stumps↗
PubMed2000

A model instrument for the documentation of outcome after nerve repair.

We present a new model for documentation and quantification of the functional outcome after nerve repair at the wrist or distal forearm level and a protocol that includes a numerical scoring system. The model, presented here along with validation and reliability test results, supports our hypothesis that the summarized test results reflecting specific functional limitations correlates well with the patient's opinion of the impact of the nerve injury on activities of daily living. Seventy patients with nerve repair were examined using the protocol. Analysis included 3 factors: sensory domain (sensory innervation, tactile agnosis, and finger dexterity), motor domain (motor innervation and grip strength), and pain/discomfort domain (hyperaesthesia and cold intolerance). The analysis explained 73% of the variances of the variables and the variables had a logical distribution between the factors. Analysis of internal consistency demonstrated good homogeneity. A calculated total score correlated strongly with the patients' global estimation of the impact of the injury on activities of daily living and the summary of sensory and pain/discomfort domains correlated significantly with the Medical Research Council S0-S4 scale. The presented model represents a useful new tool for evaluation of the functional outcome after nerve injury and repair.

Adolescent↗
PubMed2000

Assessment of functional outcome after nerve repair in a longitudinal cohort.

To investigate the temporal changes in the results of clinical tests of the functional outcome after nerve repair, we followed up 19 patients periodically over a four year period after repair of the median or ulnar nerve at the forearm. Between the first and last follow-up four of the instruments used--Semmes-Weinstein monofilaments, manual muscle testing, Sollerman grip test, and Jamar dynamometer--indicated significant and moderate to large improvements. A moderate and significant improvement was also noted during the same period in patients' estimation of pain or discomfort. Results of the two-point discrimination test did not change significantly over time. Most changes occurred during the first postoperative year, and thereafter it was principally motor function that improved. We conclude that four of the six used tests showed useful temporal dynamics during the follow-up time. The lack of responsiveness in two-point discrimination test suggests that other or complementary test instruments should be used for assessment of tactile gnosis after nerve repair.

Adolescent↗
PubMed1999

Effect of different frequencies of preventive maintenance treatment on periodontal conditions. 5-Year observations in general dentistry patients.

The protocol for this study was designed to evaluate the effects of supportive recall treatments provided with different frequencies, viz. at 3-, 6-, 12- and 18-month intervals. The subjects for the study were recruited from patients attending a public, general dentistry clinic. Prior to baseline, the subjects were given necessary dental treatments to provide a proper baseline for the study. Baseline, intermittent and final recordings included scores of dental plaque, bleeding on probing, probing depth and probing attachment level. Results were evaluated statistically by intergroup comparisons of changes for the various parameters from baseline to final examination after 5 years. The analyses showed some advantage to shorter recall intervals for plaque and bleeding scores. Although not statistically significant, there was a trend suggesting some rebound of sites > or =6 mm deep at the end of the study for the 18-month group, but not for the other groups. Similarly, there was a trend that the 18-month group showed a higher percentage of buccal/lingual furcation sites with attachment loss > or = 1.0 mm than the other groups. Apart from these trends, the analyses failed to demonstrate differences between the groups for either changes of probing depths or probing attachment levels. The negative observations included identification of individuals with 'disease progression' in the various groups, using a series of arbitrary definitions for this parameter. The results of this trial suggest that recall intervals extended to a year may be acceptable for the purpose of reducing periodontal disease progression in individuals with a history of limited susceptibility to the disease.

Adult↗
PubMed1999

Hearing as substitution for sensation: a new principle for artificial sensibility.

We describe a new principle for artificial sensibility of the hand based on sense substitution, using hearing as substitution for loss of sensation. The experiments were performed on 3 patients who had recently undergone isolated median nerve repair, 1 patient with replantation of an amputated forearm, 1 patient using a myoelectric prosthesis, and 4 patients using cosmetic prostheses. Small condenser microphones were mounted dorsally on the distal phalanges of multiple fingers of the nonsensate hands or prostheses. The friction sound, reflecting the vibrotactile stimuli generated by the moving touch of the objects, was picked up by the microphones and processed in a stereo amplifier that separated signals from individual fingers into different channels. The signals were transmitted to earphones, making possible a spatial resolution that enabled identification of each finger by the generated acoustic stimuli. Since the friction sound is characteristic of specific surfaces and textures, the corresponding acoustic stimuli made possible identification of different textures, such as glass, metal, wood, and paper, without using vision. We conclude that sense substitution using specifically processed acoustic stimuli as a substitute for sensation may represent a useful principle for generation of artificial sensibility in prostheses or hands lacking sensibility due to lesions in the peripheral or central nervous system or because of neurologic disease.

Acoustic Stimulation↗
PubMed1998

Artificial sensibility based on the use of piezoresistive sensors. Preliminary observations.

Piezoresistive sensors, applied to the fingertips of non-sensate fingers, were used for the detection of touch and pressure in four patients with recent median nerve repairs, and in one patient using a myoelectric prosthesis. The signals from the sensors, produced by the tactile stimuli, were processed and transposed as electrical stimuli to sensate skin of the ipsi- or contralateral arm by the use of skin electrodes. With this setup the test subjects could rapidly learn to differentiate between tactile stimuli applied to different fingers, thereby regaining spatial resolution in the hand. All five patients rapidly improved their ability to regulate the power of pinch grip without the help of vision. The patient with a hand prosthesis rapidly learned to discriminate between four different levels of pressure, applied to the thumb by four different Semmes--Weinstein monofilaments (75, 125, 280 and 450 g). These results indicate that the system is of potential value for patients lacking sensibility or using prostheses.

Adult↗
PubMed1997

Sensory function after median nerve decompression in carpal tunnel syndrome. Preoperative vs postoperative findings.

The sensory recovery was monitored for up to 1 year after decompression of the median nerve in 69 patients with carpal tunnel syndrome. Special attention was paid to the rate of recovery, the importance of constant or intermittent numbness or paraesthesiae preoperatively and the influence of gender. Most patients with numbness/paraesthesiae and those with abnormal two-point discrimination recovered within 10 days. Perception of touch and vibration recovered within 3 weeks in most patients but those with abnormal nerve conduction/sensory amplitude recovered slowly during follow-up. After 1 year patients with intermittent preoperative symptoms were significantly more likely to achieve normal nerve conduction and perception of touch. Women were more likely to achieve normal nerve conduction and perception of touch. A comparison of recovery between matched men and women with identical preoperative status showed no significant difference. The results indicate the importance of early treatment of carpal tunnel syndrome.

Adult↗
PubMed1997

Tubular versus conventional repair of median and ulnar nerves in the human forearm: early results from a prospective, randomized, clinical study.

Injury to a peripheral nerve is followed by local synthesis and release of neurotrophic factors of importance for the regeneration process. This concept was adopted for repair of transected human median and ulnar nerves in the forearm. As an alternative to conventional microsurgical repair of the nerve trunk, silicone tubes of appropriate size were used to enclose the injury zone, intentionally leaving a gap measuring 3-4 mm between the nerve ends inside the tube. The early results from a prospective, randomized, clinical study comparing this principle with conventional microsurgical technique for repair of human median and ulnar nerves, is presented. Eighteen patients (14 men and 4 women), aged 12-72 (mean, 29.5) years, were randomized to either tubulization (11 cases) or conventional microsurgical repair (7 cases). A battery of tests for sensory and motor functions of the hand were carried out at regular intervals for up to 1 year after surgery. The results show no difference between the both techniques, with the exception of perception of touch, which showed a significant difference (p < .05) at the 3-month checkup in favor of the tubulization technique. At re-exploration 11 months after the initial procedure (1 case), the former gap was replaced by regenerated nerve tissue in direct continuity with the proximal and distal parts of the nerve trunk, the exact level of the former injury being impossible to identify. Study data demonstrate an intrinsic capacity of human major nerve trunks to reconstruct themselves in a preformed space when an optimal environment is offered and the surgical trauma is minimized.

Adolescent↗