Electrodiagnostic studies in Guillain-Barre syndrome

The Guillain-Barre syndrome (GBS) is a monophasic (sub)acute inflammatory demyelinating predominantly motor polyradiculo-neuropathy. Clinical criteria have been proposed by Asbury (Asbury et aI., 1978; Asbury and Cornblath, 1990). GBS is a selflimiting disease, however, up to 30% of the patients may need temporary artificial ventilation; about 15% remain disabled and mortality is estimated to be up to 5%. Therefore, GBS must be regarded as a serious disease. Plasma exchange (PE) and more recently high dose immune globulins ([vIg) have been proved to be succesful in shortening the duration of the disease, the duration of artificial ventilation and to improve outcome at 6 months (GBS study group, 19- 85; van del' Meche et aI., 1992; French cooperative group, 1992). In contrast to immune globulin therapy, plasma exchange is not always possible for haemodynamic reasons. In addition it is generally not feasible in children, not in all hospitals available, and is in general rather cumbersome. Therefore in the multicentre Dutch Guillain-Barn: Study the effectiveness of immune globulins versus plasma exchange was evaluated in 150 patients, with a main aim to demonstrate at least equal efficacy. This study revealed therapeutic effectiveness of both therapies with a limited but significant superiority of immune globulins over plasma exchange (van del' Meche et aI., 1992). [n the Dutch Guillain-Barre trial each patient was tested electrodiagnostically three times in an early stage of the disease according to a rigid protocol. The results of these electro diagnostic studies are the subject of this thesis

Chronic motor neuropathies: response to interferon-beta1a after failure of conventional therapies

OBJECTIVES: The effect of interferon-beta1a (INF-beta1a; Rebif) was studied in patients with chronic motor neuropathies not improving after conventional treatments such as immunoglobulins, steroids, cyclophosphamide or plasma exchange. METHODS: A prospective open study was performed with a duration of 6-12 months. Three patients with a multifocal motor neuropathy and one patient with a pure motor form of chronic inflammatory demyelinating polyneuropathy were enrolled. Three patients had anti-GM1 antibodies. Treatment consisted of subcutaneous injections of IBF-beta1a (6 MIU), three times a week. Primary outcome was assessed at the level of disability using the nine hole peg test, the 10 metres walking test, and the modified Rankin scale. Secondary outcome was measured at the impairment level using a slightly modified MRC sumscore. RESULTS: All patients showed a significant improvement on the modified MRC sumscore. The time required to walk 10 metres and to fulfil the nine hole peg test was also significantly reduced in the first 3 months in most patients. However, the translation of these results to functional improvement on the modified Rankin was only seen in two patients. There were no severe adverse events. Motor conduction blocks were partially restored in one patient only. Anti-GM1 antibody titres did not change. CONCLUSION: These findings indicate that severely affected patients with chronic motor neuropathies not responding to conventional therapies may improve when treated with INF-beta1a. From this study it is suggested that INF-beta1a should be administered in patients with chronic motor neuropathies for a period of up to 3 months before deciding to cease treatment. A controlled trial is necessary to confirm these findings

Three-dimensional facial volume analysis using algorithm-based personalized aesthetic templates

Three-dimensional stereophotogrammetry is commonly used to assess volumetric changes after facial procedures. A lack of clear landmarks in aesthetic regions complicates the reproduction of selected areas in sequential images. A three-dimensional volumetric analysis was developed based on a personalized aesthetic template. The accuracy and reproducibility of this method were assessed. Six female volunteers were photographed using the 3dMDtrio system according to a clinical protocol, twice at baseline (T1) and twice after 1 year (T2). A styrofoam head was used as control. A standardized aesthetic template was morphed over the baseline images of the volunteers using a coherent point drift algorithm. The resulting personalized template was projected over all sequential images to assess surface area differences, volume differences, and root mean square errors. In 12 well-defined aesthetic areas, mean average surface area and volume differences between the two T1 images ranged from -7.6 mm(2) to 10.1 mm(2) and -0.11 cm(3) to 0.13 cm(3) , respectively. T1 root mean square errors ranged between 0.24 mm and 0.62 mm (standard deviation 0.18-0.73 mm). Comparable differences were found between the T2 images. An increase in volume between T1 and T2 was only observed for volunteers who gained in body weight. Personalized aesthetic templates are an accurate and reproducible method to assess changes in aesthetic areas

Motor Nerve Conduction Tests in Carpal Tunnel Syndrome

Background: For the preoperatively often required confirmation of clinically defined carpal tunnel syndrome (CTS), sensory as well as motor nerve conduction studies can be applied. The aim of this study was to test the sensitivity of specific motor nerve conduction tests in comparison with, as well as in addition to, sensory nerve conduction tests.Methods: In 162 patients with clinically defined CTS, sensory and motor nerve conduction tests were performed prospectively. Sensitivity and specificity of all tests were computed. Also, Receiver Operating Characteristic (ROC) analyses were conducted.Results: Sensitivity for all sensory tests was at least 79.4% (DIG1). All tests had a specificity of at least 95.7%. The motor conduction test with the highest sensitivity was the TLI-APB (81.3%); its specificity was 97.9%.Conclusion: In the electrophysiological confirmation of CTS, sensory nerve conduction tests and terminal latency index have a high sensitivity. If, however, sensory nerve action potentials cannot be recorded, all motor nerve conduction tests have a high sensitivity

The Diagnostic Sensitivity for Ulnar Neuropathy at the Elbow Is Not Increased by Addition of Needle EMG of ADM and FDI When Nerve Conduction Studies Are Normal

Introduction: The main objective of this study was to investigate whether electromyography (EMG) has additional value in the confirmation of the clinical diagnosis of ulnar nerve entrapment at the elbow (UNE) if nerve conduction studies (NCS) are normal.Methods: A prospective cross-sectional cohort observational study was conducted among patients with the clinical suspicion of UNE. A total of 199 arms were included, who were examined according to a standard neurophysiological protocol, i.e., NCS and EMG relevant to the ulnar nerve.Results: NCS were normal in 76 (38.2%) arms. No abnormal spontaneous muscle fiber activity was found with EMG in any of these cases. In 9 arms with normal NCS (11.8%), isolated abnormal MUAP configurations were found with EMG. Of these nine arms one UNE was diagnosed clinically, in which additional ultrasound and repeated NCS/EMG were negative. One had already been diagnosed with neuralgic amyotrophy and one with CTS. The other 6 arms had additional diagnostics which did not reveal an UNE.Conclusion: EMG as part of the standard neurophysiological protocol exclusively in the confirmation of the clinical diagnosis of UNE has limited added value if NCS are normal in a high prior-odds setting. However, removing EMG may prevent detecting concomitant and/or additional differential diagnoses

Comparing the influence of mixed reality, a 3D viewer, and MRI on the spatial understanding of brain tumours

Background: Multiple 3D visualization techniques are available that obviates the need for the surgeon to mentally transform the 2D planes from MRI to the 3D anatomy of the patient. We assessed the spatial understanding of a brain tumour when visualized with MRI, 3D models on a monitor or 3D models in mixed reality.Methods: Medical students, neurosurgical residents and neurosurgeons were divided into three groups based on the imaging modality used for preparation: MRI, 3D viewer and mixed reality. After preparation, the participants needed to position, scale, and rotate a virtual tumour inside a virtual head of the patient in the same orientation as the original tumour would be. Primary outcome was the amount of overlap between the placed tumour and the original tumour to evaluate accuracy. Secondary outcomes were the position, volume and rotation deviation compared to the original tumour.Results: A total of 12 medical students, 12 neurosurgical residents, and 12 neurosurgeons were included. For medical students, the mean amount of overlap for the MRI, 3D viewer and mixed reality group was 0.26 (0.22), 0.38 (0.20) and 0.48 (0.20) respectively. For residents 0.45 (0.23), 0.45 (0.19) and 0.68 (0.11) and for neurosurgeons 0.39 (0.20), 0.50 (0.27) and 0.67 (0.14). The amount of overlap for mixed reality was significantly higher on all expertise levels compared to MRI and on resident and neurosurgeon level also compared to the 3D viewer. Furthermore, mixed reality showed the lowest deviations in position, volume and rotation on all expertise levels.Conclusion: Mixed reality enhances the spatial understanding of brain tumours compared to MRI and 3D models on a monitor. The preoperative use of mixed reality may therefore support the surgeon to improve spatial 3D related surgical tasks such as patient positioning and planning surgical trajectories