Variants and differential diagnosis of peripheral nerve hyperexcitability

Society Proceedings / Clinical Neurophysiology 118 (2007) e9–e116

tion studies. We examined the usefulness of HVS in 19 patients with plexus lesions of different etiologies especially to detect the site of acute demyelinating lesion. Methods: 19 patients (17–82 years, mean 53.7) with unilateral plexus lesions (1–56 days from onset, mean 21.6) were examined amongst others clinically and radiologically (mostly with MRI). Serum- and/or CSF-analysis were performed in cases suspect of inflammatory etiology. HVS was undertaken to deltoideus, biceps brachii, or abductor digiti minimi muscle to examine the brachial plexus. Vastus medialis or tibialis anterior muscle were used for the lumbosacral plexus. Muscles were chosen regarding the main focus of the paresis. The measurements were performed according to a standardized protocol and the contralateral, healthy side was always used as a reference concerning latencies. Analysis was done in the usual way for motor conduction studies with the exception of the conduction velocity which cannot be determined in proximal sites. Results: Partial conduction block (PCB) could be found in 9 patients (47.4%), axonal lesion (AL) in 5 (26.3%), 4 patients (21.1%) showed combined PCB and AL. One patient had normal results (5.3%). As to be expected older lesions (2 or 3 weeks and more) tend to result in AL, younger (especially within the first 2 or 3 weeks) in PCB in our collective. Within the different etiologies no ‘‘typical’’ lesion pattern could be discerned. Conclusions: We were able to detect the site of the lesion with HVS in 68.5% of our patients. In our experience HVS is a very useful electrodiagnostic tool especially in early stages of plexus lesions. doi:10.1016/j.clinph.2006.11.083

Delayed feedback of somato-motor cortex activations modulates finger tapping results in real-time functional MR imaging—J. Gawehn 1, G. Vucurevic 1, P. Dellani 1, P. Urban 2, P. Stoeter 1 (1 Institut fu¨r Neuroradiologie, Universita¨t Mainz, 2 Klinik fu¨r Neurologie, Universita¨t Mainz) The objective of this study was to examine the effect of a slightly delayed feedback projection of real-time fMRI motor activations into the scanner on the performance of the subsequent tasks during the same session and/or on the performance during a second session one week later. All subjects were informed about the aim of the study: to modulate their cortical activation in accordance to the demand of the task. The paradigm consisted out of three 112.5-s-runs of self-paced finger tapping of the right hand with increasing demand (low, medium and high) for the modalities: strength, complexity and velocity. All measurements were performed in a 1.5 T MR scanner (Sonata, Siemens) using an eight channel head coil and the real-time fMRI software supplied by the manufacturer. Activation results were recorded online from the contralateral and ipsilateral senso-motor cortices and the supplementary motor area (SMA). In the examination group (8 volunteers), the results were projected as a column graph into the scanner with a delay of 2–3 s after the end of each run. In the control group (5 volunteers), no back-projection was performed. For evaluation, we determined the number of activated voxels and the ‘‘correctness of performance’’, i.e. the number of runs showing increasing activations with increasing demand of task. In comparison to the control group, the subjects of the feedback group showed a significantly better correlation between task

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demand and activation in the contralateral senso-motor cortex and the SMA during the second session and between the sessions. This applied as well to the number of activated voxels achieved between the runs and sessions (p < 0.05) as to the number of ‘‘correctly performed’’ runs in the sense of increasing activation from low to high task demand (p < 0.001). This improvement of modulation of cortical activation may be due to increased attention and/or a learning effect induced by delayed feedback and in future could be helpful in rehabilitation training programs. doi:10.1016/j.clinph.2006.11.084

An EEG study of Wilson’s disease—P. Gu¨nther 1, W. Hermann 2, A. Wagner 1 (1 Klinik und Poliklinik fu¨r Neurologie, Universita¨t Leipzig, 2 Paracelsus-Klinik Zwickau) Introduction: Wilson’s disease is a rare autosomal recessive disorder of copper metabolism. In addition to hepatic and extrapyramidal motor clinical symptoms, patients with Wilson’s disease also exhibit subclinical disorders of other central nervous pathways. However, abnormalities of electroencephalography are reported inconsistently and infrequently. Methods: In this study, electroencephalography was performed in 38 patients with Wilson’s disease (26 patients with the neurological form, 12 patients with the non-neurological form) undergoing long-term medicamentous therapy. Attention was paid to general slowing, focal abnormalities and epileptiform activity. Results of EEG were correlated to clinical manifestation. Results: The results of electroencephalography show normal findings in almost 80% of all investigated patients with a long course of the disease. A mild continuous slow activity occurred in 5 patients and intermitted rhythmic delta activity was seen in 2 patients with a neurologic form of hepatolenticular degeneration. A difference in the median frequency of a-rhythm between neurological form (9.1/s) and non-neurological form (9.7/s) was not significant. Epileptiform activity was shown in only one patient with coincident epilepsy. Conclusions: Patients with Wilson’s disease show normalized electroencephalographic findings in the course of the disease. Abnormal changes seem to be due to additional disturbances, respectively, secondary complications. In that regard electroencephalography is helpful in the differential diagnostic in the course of the disease. doi:10.1016/j.clinph.2006.11.085

Variants and differential diagnosis of peripheral nerve hyperexcitability—H.J. Gdynia, A.C. Ludolph, A.D. Sperfeld (Neurologische Universita¨tsklinik Ulm) Aims: Peripheral nerve hyperexcitability syndromes (PNHS) are a heterogeneous group of diseases characterized by spontaneous muscle fiber activity, e.g. myokymias and fasciculations. Acquired, hereditary and idiopathic forms are known. Antibodies to voltage-gated potassium channels (VGKCs) appear likely to be the main effector mechanism in many patients with acquired PNHS. Neuromyotonia (Isaacs’ syndrome when acquired),

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Society Proceedings / Clinical Neurophysiology 118 (2007) e9–e116

cramp-fasciculation syndrome and Morvan’s disease are phenotypic variants of PNHS. Beside of idiopathic forms the association of PNHS and autoimmune diseases is well known. Furthermore, medication with penicillamin and clofibrat, hypocalcemia and paraneoplastic autoantibodies can cause PNHS. Symptomatic therapeutical strategies are membrane stabilisation, whereas plasmapheresis and immunosuppression can be indicated in autoimmune forms. Objectives: Because of the different therapeutical approaches due to the underlying mechanisms of peripheral nerve hyperexcitability, the knowledge about the phenomenology is essential. We describe variants and differential diagnosis of PNHS. Methods: On the basis of clinical examples we describe main clinical characteristics, pathophysiological concepts and differential diagnostic aspects of PNHS. Furthermore, an overview of the literature and therapeutical strategies will be given. Results: We described the clinical phenotype, characteristic electrophysiological features and laboratory findings of 5 patients suffering from spontaneous muscle fiber activity. Among them there were 2 patients with an acquired and 2 with idiopathic PNHS, one patient suffered from ALS. Conclusion: The knowledge of the clinical picture and the typical electrophysiological features of PNHS are essential to rule out differential diagnoses like ALS. Whereas in autoimmune and paraneoplastic forms the therapy should be focused on the underlying disease, membrane stabilisation should be performed in idiopatic forms. doi:10.1016/j.clinph.2006.11.086

Influence of hormonal cycle in women on lateralization of brain activation during performing a mental rotation task— E. Gizewski, A. de Greiff, A. Baars, I. Wanke, M. Forsting (Universita¨tsklinikum, Essen) Purpose: Differences in performance or in terms of functional imaging during a spatial task are up to now described with contradicting results: there is evidence that women during mid-luteal phase perform more different than women outside this phase. Methods and materials: Functional MRI was performed in 24 female volunteers (within mid-luteal phase of menses, outside and with hormonal contraceptives). Active condition was mental rotation task in a standard-block-design. Second level analyses were performed with uncorrected p-values <0.001 for the known ROIs of this stimulus (BA 6, 7, 8, 19, 39, 40 and 44). Lateralization index was calculated using the equation SRi SLi/SRi + SLi for each area. Results: During mental rotation tests, activation in the above mentioned areas could be revealed in all three groups during performing a mental rotation task. An enhanced lateralization was revealed in women with hormonal contraceptives to the left side, the lateralization was more pronounced during the mid-luteal phase but not only to the left side. BA 19, 39 and 44 were lateralized to the right side in both during mid-luteal and menstrual phase but not under contraceptives. The performance in this test was assessed outside the scanner revealing no significant differences between the groups. Conclusion: Our results indicate that the hormonal changes over cycle time or contraceptive therapy have influences on the

lateralization of cerebral activity in a cognitive function like mental rotation task. doi:10.1016/j.clinph.2006.11.087

Isolated paraspinal myopathy: A distinct subtype of facioscapulohumeral muscular dystrophy—F. Glocker 1, G. Meng 3, M. Kottlors 2 (1 Neurologische Universita¨tsklinik Freiburg, 2 Seidel-Klinik Bad Bellingen, 3 Institut fu¨ r Humangenetik der Universita¨ t Wu¨ rzburg) Fascioscapulhumeral muscular dystrophy (FSHD) is inherited as an autosomal dominant trait and is characterized by facial and shoulder girdle weakness usually appearing in adolescence. In milder cases signs may be apparent not before late adulthood. A scapuloperoneal subtype sparing the facial muscles has been described. We present two cases with genetically confirmed FSHD with a distinct phenotype solely affecting the paraspinal muscles. Case reports: Patient 1 was a 65-year-old man with a more than 15 year history of a slowly progressive bent spine syndrome. Prior to admission the patient had multiple orthopedic diagnostic procedures and treatments. He had normal strength of the upper and lower extremities and no facial weakness. Patient 2 was a 60year-old healthy man presenting with a short history of lower back pain. He was referred to our hospital because of an MRI study of the lumbar spine revealing no disc herniation but marked atrophy of the paraspinal muscles. Family history was negative in both cases with respect to neuromuscular disorders. EMG studies of both patients revealed normal findings of the muscles of upper and lower extremities but marked myopathic changes in the paraspinal muscles. Laboratory examinations showed slightly elevated CPK levels (200–300 U/l) in patients 1 and 2. In both patients DNA testing revealed restriction fragments consistent with a 3 kb deletion at the D4Z4 locus (FSHD-repeat) on chromosome 4q35. The fragment sizes of the D4Z4 locus varies in the population between 40 and 320 kb. Only fragments <38 kb (EcoRI-digestion) and <35 kb (EcoRI + Bln I, double digestion), respectively, are diagnostic for FSHD. The size of the smaller fragments following EcoRI and double digestion was 33–30 kb in both Patients. Conclusions: (i) Patients with the FSHD on chromosome 4q35 may present with a phenotype of isolated paraspinal mypoathy. (ii) In cases with paraspinal muscular atrophy in MRI and/or bent spine syndrome an underlying FSHD should be considered. doi:10.1016/j.clinph.2006.11.088

Temporal activation patterns of lateralized cognitive and task control processes in the human brain—R. Gobbele´ 1, U. Stegelmeyer 1, T.D. Waberski 1, K.E. Stephan 2, K. Rache 1, H. Buchner 1, G.R. Fink 1 (1 Universita¨tsklinikum Aachen, 2 Institut fu¨r Medizin, Forschungszentrum Ju¨lich) Lexical and visuospatial information processing show hemispheric specialization: using fMRI and identical word stimuli for both tasks, a recent study demonstrated left-hemispheric activations (including Broca’s area) associated with letter detection decisions (including Broca’s area) and right hemisphere activa-