Background: The underlying pathophysiological mechanisms of chronic Whiplash Associated Disorders (WAD) are not fully understood. More knowledge of morphology is needed to better understand the disorder, improve diagnostics and treatments. The aim was to investigate dorsal neck muscle volume (MV) and muscle fat infiltration (MFI) in relation to self-reported neck disability among 30 participants with chronic WAD grade II-III compared to 30 matched healthy controls.

Methods: MV and MFI at spinal segments C4 through C7 in both sexes with mild- to moderate chronic WAD (n = 20), severe chronic WAD (n = 10), and age- and sex matched healthy controls (n = 30) was compared. Muscles: trapezius, splenius, semispinalis capitis and semispinalis cervicis were segmented by a blinded assessor and analyzed.

Results: Higher MFI was found in right trapezius (p = 0.007, Cohen’s d = 0.9) among participants with severe chronic WAD compared to healthy controls. No other significant difference was found for MFI (p = 0.22–0.95) or MV (p = 0.20–0.76).

Conclusions: There are quantifiable changes in muscle composition of right trapezius on the side of dominant pain and/or symptoms, among participants with severe chronic WAD. No other statistically significant differences were shown for MFI or MV. These findings add knowledge of the association between MFI, muscle size and self-reported neck disability in chronic WAD.

Funktionell neurokirurgi är ett samlingsnamn för en bred arsenal av neurokirurgiska metoder för att lindra besvär vid olika neurogena tillstånd. Syftet är genomgående att förbättra livskvalitet, och verksamheterna präglas av ett uttalat multidisciplinärt och tvärprofessionellt samarbete. Detta underlättar en god patientselektion, vilket är helt avgörande för att uppnå ett lyckat resultat. Med rätt urval och uppföljning erbjuder dessa ingrepp säker och effektiv lindring eller till och med bot för notoriskt svårbehandlade och ofta starkt funktionsnedsättande tillstånd.

Essential tremor is a common movement disorder with an unclear origin. Emerging evidence suggests the role of the cerebellum and the thalamus in tremor pathophysiology. We examined the two main neurotransmitters acting inhibitory (GABA+) and excitatory (Glx) respectively, in the thalamus and cerebellum, in patients diagnosed with severe essential tremor. Furthermore, we also investigated the relationship between determined neurotransmitter concentrations and tremor severity in the essential tremor patients.

Prognostic models play an important role in the clinical management of cervical radiculopathy (CR). No study has compared the performance of modern machine learning techniques, against more traditional stepwise regression techniques, when developing prognostic models in individuals with CR. We analysed a prospective cohort dataset of 201 individuals with CR. Four modelling techniques (stepwise regression, least absolute shrinkage and selection operator [LASSO], boosting, and multivariate adaptive regression splines [MuARS]) were each used to form a prognostic model for each of four outcomes obtained at a 12 month follow-up (disability-neck disability index [NDI]), quality of life (EQ5D), present neck pain intensity, and present arm pain intensity). For all four outcomes, the differences in mean performance between all four models were small (difference of NDI<1 point; EQ5D<0.1 point; neck and arm pain<2 points). Given that the predictive accuracy of all four modelling methods were clinically similar, the optimal modelling method may be selected based on the parsimony of predictors. Some of the most parsimonious models were achieved using MuARS, a non-linear technique. Modern machine learning methods may be used to probe relationships along different regions of the predictor space.

Study Design. A prospective randomized multicenter trial. Objective. To investigate the effects of surgery with either structured postoperative physiotherapy or standard postoperative approach on neck-related headache in patients with cervical radiculopathy. Secondary, to investigate associations between change in neck-related headache and change in neck muscle endurance, neck mobility, or neck pain. Summary of Background Data. The effect of physiotherapy on individuals with neck-related headache after surgery for cervical radiculopathy due to magnetic resonance imaging-verified disc disease is unknown. Methods. One hundred six patients with neck-related headache and participating in a randomized controlled trial evaluating the additional effects of physiotherapy after surgery for cervical radiculopathy were included. Patients were randomized preoperatively to structured postoperative physiotherapy (n = 51) or the standard postoperative approach (n = 55). Outcome measures were headache intensity and neck pain intensity, neck muscle endurance, and neck mobility. Measures were obtained preoperatively and at 6 weeks, 3 months, 6 months, and 1 year postoperatively. Results. Headache intensity significantly changed from baseline to 1 year postoperatively (P < 0.001) in both groups.Post-hoctests showed a significant difference between baseline and 6 weeks (P <= 0.05). No significant differences were found between groups (P > 0.05) or between-group differences in changes over time (P > 0.05). The change in current headache intensity over time was associated with a change in current neck pain intensity over time (P = 0.003, beta = 0.40). Conclusion. There was a significant improvement in headache intensity 1 year postoperatively in patients with cervical radiculopathy and neck-related headache, but there were no differences between groups over time. Change in current headache intensity was only associated with a change in current neck pain intensity.

Background: Optics can be used for guidance in deep brain stimulation (DBS) surgery. The aim was to use laser Doppler flowmetry (LDF) to investigate the intraoperative optical trajectory along the ventral intermediate nucleus (VIM) and zona incerta (Zi) regions in patients with essential tremor during asleep DBS surgery, and whether the Zi region could be identified. Methods: A forward-looking LDF guide was used for creation of the trajectory for the DBS lead, and the microcirculation and tissue greyness, i.e., total light intensity (TLI) was measured along 13 trajectories. TLI trajectories and the number of high-perfusion spots were investigated at 0.5-mm resolution in the last 25 mm from the targets. Results: All implantations were done without complications and with significant improvement of tremor (p < 0.01). Out of 798 measurements, 12 tissue spots showed high blood flow. The blood flow was significantly higher in VIM than in Zi (p < 0.001). The normalized mean TLI curve showed a significant (p < 0.001) lower TLI in the VIM region than in the Zi region. Conclusion: Zi DBS performed asleep appears to be safe and effective. LDF monitoring provides direct in vivomeasurement of the microvascular blood flow in front of the probe, which can help reduce the risk of hemorrhage. LDF can differentiate between the grey substance in the thalamus and the transmission border entering the posterior subthalamic area where the tissue consists of more white matter tracts.

BACKGROUND: Rehabilitation approaches should be based on an understanding of the mechanisms underpinning functional recovery. Yet, the mediators that drive an improvement in post-surgical pain-related disability in individuals with cervical radiculopathy (CR) are unknown. The aim of the present study is to use Bayesian networks (BN) to learn the probabilistic relationships between physical and psychological factors, and pain-related disability in CR.

METHODS: We analysed a prospective cohort dataset of 201 post-surgical individuals with CR. In all, 15 variables were used to build a BN model: age, sex, neck muscle endurance, neck range of motion, neck proprioception, hand grip strength, self-efficacy, catastrophizing, depression, somatic perception, arm pain intensity, neck pain intensity and disability.

RESULTS: A one point increase in a change of self-efficacy at 6 months was associated with a 0.09 point decrease in a change in disability at 12 months (t = -64.09, p < .001). Two pathways led to a change in disability: a direct path leading from a change in self-efficacy at 6 months to disability, and an indirect path which was mediated by neck and arm pain intensity changes at 6 and 12 months.

CONCLUSIONS: This is the first study to apply BN modelling to understand the mechanisms of recovery in post-surgical individuals with CR. Improvements in pain-related disability was directly and indirectly driven by changes in self-efficacy levels. The present study provides potentially modifiable mediators that could be the target of future intervention trials. BN models could increase the precision of treatment and outcome assessment of individuals with CR.

SIGNIFICANCE: Using Bayesian Network modelling, we found that changes in self-efficacy levels at 6-month post-surgery directly and indirectly influenced the change in disability in individuals with CR. A mechanistic understanding of recovery provides potentially modifiable mediators that could be the target of future intervention trials.

Objective Electrical neuromodulation by deep brain stimulation (DBS) is a well-established method for treatment of severe essential tremor (ET). The mechanism behind the tremor relieving effect remains largely unknown. Our aim of this study was to evaluate alterations in proteomics pre- and post-DBS in patients diagnosed with severe ET. Materials and Methods Ten right-handed ET patients were included in this study. Cerebrospinal fluid (CSF) was obtained by lumbar puncture preoperatively (N = 10) and six months postoperatively (N = 7). The samples were analyzed by high sensitive liquid chromatography tandem mass spectrometry. Results Twenty-two proteins were statistically significantly altered in the CSF of ET patients before and after DBS treatment. Downregulated proteins were involved in regulatory processes of protein activation, complement activation, humoral immune response as well as acute inflammatory response. The upregulated proteins were involved in pathways for cell secretion, adhesion as well as response to axon injury. Conclusions DBS in ET patients effects the neurochemical environment in the CSF. These findings further elucidate the mechanisms of DBS and may lead to new biomarkers for evaluating the effect of DBS treatment.