Transcutaneous Nerve Bundle Stimulation for Dexterous Hand Grasp Patterns: Development and Exploration of an Alternative Stimulation Method

Impairment of the hand following a neurological injury such as stroke is a major contributing factor to the loss of independence and self-sufficiency. Neuromuscular Electrical Stimulation (NMES) is a widely utilized technique to help alleviate lost muscle strength by electrically eliciting muscle contractions. However, conventional NMES applied directly over the muscle belly often faces various limitations, which prevent long-term use and efficacy. Traditional NMES techniques induce rapid muscle fatigue due to non-physiological activation of fibers resulting in a decline of muscle force. For the hand, stimulation at the skin surface typically only activates the superficial extrinsic hand muscles, leading to limited multi-joint control. To overcome these limitations, we sought to develop an alternative stimulation technique that used a high-density surface electrode array to directly target major nerve bundles at a location more proximal to the muscles. First, we designed an automated stimulation paradigm to characterize the different patterns of finger flexion elicitable via the nerve stimulation method. Randomized pairs in the electrode array were used to search for the best stimulation locations. We demonstrated that the nerve stimulation can generate a variety of single and multi-finger flexion patterns, with selective sets of nerve fiber activation and high activation redundancy. Secondly, we compared the force sustainability of the proximal nerve stimulation with conventional muscle belly stimulation. We found that, with prolonged force-matched stimulations, the proximal nerve stimulation technique can significantly delay the decline of force production over time, which allowed us to elicit sustained muscle force output. Lastly, we investigated the ability of the proximal nerve stimulation to activate both the superficial and deep extrinsic finger flexors. We obtained ultrasound images of the cross section of the flexor muscles in the forearm, and image deformation was used as a surrogate measure of muscle contraction. We found that superficial and deep muscles could be separately or concurrently activated. Overall, this work demonstrated the appealing features of our nerve stimulation method in selectively recruiting different finger flexor muscles with sustained activation. The outcomes also lay the theoretical foundation for further development of proximal nerve stimulation as an alternative approach for effective hand rehabilitation.Doctor of Philosoph

Who profits from concentrated exposure treatment for Obsessive-Compulsive Disorder (OCD)? A quality assurance project from the OCD-team in Bergen

Obsessive-Compulsive Disorder (OCD) is a debilitating psychological disorder characterized by bothersome and intrusive thoughts (obsessions) associated with anxiety and distress that the patient tries to reduce or control through compulsive behavior. The main recommended treatment for OCD is Cognitive behavioral therapy (CBT), including exposure and response prevention (ERP). At the OCD-team in Bergen, Norway, ERP is offered in a concentrated treatment format across four consecutive days. However, not all patients profit from ERP treatment, and it is an important task to establish which patients respond to this treatment and who does not. This thesis set out to investigate whether the concentrated treatment works for patients with certain characteristics. In paper I, we examined the relationship between treatment outcome and hardiness or resilience; a personality trait regarding sense of meaning and commitment, locus of control, and preferences for challenges. In paper II, we explored the relationship between treatment outcome and the personality trait sensory processing sensitivity. In the paper III, we investigated whether post-treatment levels of depression, anxiety and OCD were related to treatment outcome. We report on data from a quality assurance database at an outpatient OCD-clinic in Bergen, Norway. The quality assurance database was established during the national implementation of publicly available ERP treatment in Norway in order to monitor the treatment delivered by specialized OCD-teams. Symptoms were measured pre- and post-treatment, and at 3-6 month follow-up. The concentrated treatment was found to be highly effective, and the majority of patients had a clinically significant and lasting improvement in OCD symptoms. No adverse effects were detected. Results showed that the treatment was equally efficient for patients scoring high and low on resilience and sensory processing sensitivity. This is an important finding, as research suggest that therapists might be reluctant to offer exposure treatment to patients considered too “fragile” or “sensitive” for exposure tasks. However, the combination of subclinical levels of depression, anxiety, and OCD symptoms at post-treatment was associated with higher levels of OCD-symptoms at follow-up. This is in line with previous research, and points to the importance of full recovery post-treatment. We recommend clinicians to pay attention to patients with residual symptoms to reduce risk of relapse. We also recommend clinicians to offer evidence based ERP treatment to patients regardless of scores on sensitivity and resilience. Important limitations in the current thesis include the reliance on self-report data, whether our results can be generalized to other treatment formats, and the lack of other possibly relevant predictor variables. We recommend future studies to investigate whether our findings hold true in other samples and treatment formats. We argue that quality assurance as an integrated part of treatment provides safety for the patients and a unique opportunity for improvements and continued development of evidence based treatments.Doktorgradsavhandlin

Saving Bones: a direct comparison of FTIR-ATR, whole bone percent nitrogen, and NIR

89th Annual Meeting of the American-Association-of-Physical-Anthropologists (AAPA), Los Angeles, CA, APR 15-18, 202

Muscle activation patterns in shoulder impingement patients

Introduction: Shoulder impingement is one of the most common presentations of shoulder joint problems 1. It appears to be caused by a reduction in the sub-acromial space as the humerus abducts between 60o -120o – the 'painful arc'. Structures between the humeral head and the acromion are thus pinched causing pain and further pathology 2. Shoulder muscle activity can influence this joint space but it is unclear whether this is a cause or effect in impingement patients. This study aimed to observe muscle activation patterns in normal and impingement shoulder patients and determine if there were any significant differences. Method: 19 adult subjects were asked to perform shoulder abduction in their symptomatic arm and non-symptomatic. 10 of these subjects (age 47.9 ± 11.2) were screened for shoulder impingement, and 9 subjects (age 38.9 ± 14.3) had no history of shoulder pathology. Surface EMG was used to collect data for 6 shoulder muscles (Upper, middle and lower trapezius, serratus anterior, infraspinatus, middle deltoids) which was then filtered and fully rectified. Subjects performed 3 smooth unilateral abduction movements at a cadence of 16 beats of a metronome set at 60bpm, and the mean of their results was recorded. T-tests were used to indicate any statistical significance in the data sets. Significance was set at P<0.05. Results: There was a significant difference in muscle activation with serratus anterior in particular showing a very low level of activation throughout the range when compared to normal shoulder activation patterns (<30%). Middle deltoid recruitment was significantly reduced between 60-90o in the impingement group (30:58%).Trends were noted in other muscles with upper trapezius and infraspinatus activating more rapidly and erratically (63:25%; 60:27% respectively), and lower trapezius with less recruitment (13:30%) in the patient group, although these did not quite reach significance. Conclusion: There appears to be some interesting alterations in muscle recruitment patterns in impingement shoulder patients when compared against their own unaffected shoulders and the control group. In particular changes in scapula control (serratus anterior and trapezius) and lateral rotation (infraspinatus), which have direct influence on the sub-acromial space, should be noted. It is still not clear whether these alterations are causative or reactionary, but this finding gives a clear indication to the importance of addressing muscle reeducation as part of a rehabilitation programme in shoulder impingement patients