Microsoft word - abstracts march 2011.doc

Infantile Spasms and Treatment. J.
Martinez, S. Penfold, Z. Agirre-Arrizubieta.
conditioning stimuli, however, indicate that in (Department of Clinical Neurophysiology, East
some groups of fibres accumulation of potassium Kent Hospitals University NHS Foundation
may also play a significant role. This may have Trust, UK).
implications when interpreting results in muscle children with infantile spasms (IS) during a three- year-period (2007-2010) at East Kent Hospitals. Corneal Confocal Microscopy: A
Novel Means to Detect Nerve Fibre Damage in
obtain aetiology, neurological findings, MRI, Idiopathic
Neuropathy.
video-EEG studies, treatment and follow-up. Marshall¹, M. Tavakoli², M. Roberts¹, N.
Efron³, A.J. Boulton AJ ², R.A. Mallik² .
studied. Aetiology: symptomatic in 9 patients and (Salford Royal NHS Foundation Trust, UK¹,
unknown in 1. Most common IS: flexion in Central Manchester Foundation Trust and
43.6% and mixed in 36.4%. Therapeutic response University
Manchester,
was broadly satisfactory: 60% seizure free; 20% Queensland
University
Technology,
partial response, 10% with more than 50% Australia³).
decrease and 10% with no IS but other seizures. Idiopathic small fibre neuropathy (ISFN) Polytherapy: noted in 70% of patients. At follow- is associated with intraepidermal nerve fibre loss up, deve1opment was normal in 1 patient and and an increased prevalence of impaired glucose delayed in 9 (2 mild, 3 moderate and 2 profound). tolerance (IGT). It has been suggested that the dysglycaemia of IGT and additional metabolic challenging. In East Kent Hospitals, the risk factors contribute to small nerve fibre damage commonest current therapy is a combination of 2 of the following: ACTH, steroids, vigabatrin and topiramate. The outcome and prognosis of IS matched control subjects underwent detailed appeared similar or mildly improved compared evaluation of neuropathic symptoms, neurological with previous experience. However, safer and deficits (Neuropathy deficit score (NDS); Nerve more effective therapies are needed to improve Conduction Studies (NCS); Quantitative Sensory Testing (QST) and Corneal Confocal Microscopy (CCM)) to quantify small nerve fibre pathology. Velocity Recovery Cycles in Biceps
patients with ISFN had significant neuropathic Brachii: New Insights Into The Origin of The
symptoms, NDS, NCS and QST except for warm Early Supernormality. C.E.G Moore1,3, R.
thresholds were normal. Corneal sensitivity was Arunachalam2 and D.C. Allen.2,4 (Departments
reduced and CCM demonstrated significant of Clinical Neurophysiology Portsmouth NHS
reductions in corneal nerve fibre density Trust1 and Southampton University Hospital
(P<0.0001), nerve branch density (P<0.0001), NHS Trust2 and Universities of Portsmouth3
nerve fibre length (P<0.0001) and an increase in and Southampton4, UK).
nerve fibre tortuosity (P<0.0001). These parameters did not differ between ISFN patients conduction velocity recovery cycles (VRCs) using with and without IGT or correlate with BMI, paired stimuli are technically demanding and time consuming. We have previously reported the use of an automated computer driven methods to means to detect early small nerve fibre damage in investigate VRCs in tibialis anterior (TA). This patients with ISFN and metabolic abnormalities has shown promise in the investigation of muscle disease, in particular critical illness myopathy. Are There Differences Between Han
investigation of biceps. Muscle fibre potentials Chinese and Caucasians in Transcranial
were recorded using standard technique for direct Magnetic Stimulation (TMS) Parameters?
muscle stimulation. VRCs were recorded with 1, Xiang Yi¹, K. Fisher², K. Mansoor³, Ming Lai³,
2 and 5 conditioning stimuli (10ms apart) prior to Baker².
(Mechanical
the test stimulus. The interstimulus intervals (ISI) Engineering¹,
Institute
Neuroscience²,
between the last conditioning stimulus and the test Newcastle
University,
Victoria
Infirmary³, Newcastle, UK).
biceps was greater than in TA. In addition there studying a range of TMS parameters in Chinese were distinct differences in the amount of early and Caucasian subjects. Sixteen subjects were supernormality after 1, 2 or 5 conditioning studied in each group. A circular coil at the vertex stimuli. The early supernormality has hitherto was used for stimulation, whilst recording surface been explained purely in terms of membrane electromyograms (EMG) from right first dorsal capacitance and should be independent of the interosseous. In the passive state we measured number of conditioning pulses. Our findings of motor evoked potential (MEP) threshold, MEP recruitment, short interval intracortical inhibition like Angelman syndrome , brain malformation or (SICI) and intracortical facilitation (ICF). The MEP threshold, recruitment and silent period features of two adult patients with MSNE and discuss diagnostic and management challenges in higher passive thresholds (p<0.01), less inhibition this difficult to treat epilepsy syndrome. The in of the motor response (SICI p< 0.01 ) and the recognition of MSNE resulted in the correct silent period was shorter (p< 0.05 ). identification of Angelman syndrome in one patient who was otherwise considered to have Cortical Reorganisation in MND? A
learning disability of undetermined aetiology. Study Using Pharmacological fMRI. S. Azam.
(Royal Free Hospital. London, UK).
Examining the Reproducibility of
Median Motor Nerve Excitability Testing. J.C.
(MND) progresses there may be pathological or McHugh1,
Reilly2,
Connolly1.
compensatory changes in cortical motor network (Department of Clinical Neurophysiology, St.
Vincent’s Hospital Group, Dublin, Ireland1
representation, which may be due to excitotoxic and Department of Neural Engineering,
damage of local inhibitory circuits leading to Trinity College Dublin, Ireland2).
inappropriate activation of the motor pathway or due to increased peripheral motor effort leading to functional assessment of axonal membrane function in peripheral nerve, and the technique has potential for use in longitudinal studies. imaging of the blood oxygentation response (BOLD-fMRI) during a calibrated handgrip task reliability of nerve excitability in a healthy cohort. of 5-30% maximum grip strength was performed in 12 healthy controls, 12 MND subjects and 12 motor excitability studies performed by the same subjects with multifocal motor neuropathy operator on three occasions (twice on the same (MMN), under placebo (i.v. saline) or midazolam day, and once after one week). ANOVA was conditions and images analysed with statistical used to analyse and compare the within-subject and between-subject variances for different fMRI signal increases were seen in all groups in contralateral primary sensorimotor cortex and testing had excellent reproducibility. The ipsilateral cerebellum, and statistically similar parameters with the greatest reproducibility were decreases in BOLD activation of the cortical superexcitability and minimum I/V (current threshold) slope. F-ratio of between-subject versus within-subject variance 7.30 (p < 5x10-6) motor cortex reorganisation in patients with for superexcitability and 7.0 (p < 5x10-5) for MND, using this calibrated motor paradigm; the minimum I/V slope). The least reproducible parameters were strength-duration time constant, following midazolam in all groups suggests that and threshold parameters such as rheobase, in neuronal inhibition via GABA potentiation is not which the between-subject and within-subject differences were not significantly different. Conclusion: Nerve excitability testing is Myoclonic Status in Nonprogressive
a reliable test over time, and should be suitable Encephalopathies (MSNE) – Presentation in
for use in longitudinal patient studies. Two Adult Cases. R. Ramdass, M. Jones, R.
MacDonagh, H. Kargwell, A. Marshall, R.
Measures
Peripheral
Mohanraj. (Departments of Neurology and
Excitability Demonstrate Rapid And Sustained
Neurophysiology, Royal Salford Hospitals
Improvement in Nerve Function Following
NHS Trust, Salford, UK).
Renal Transplantation. C.E.G. Moore1, 3, M.
Todd2, J. Mason2, M. Connell2. (Departments
of Clinical Neurophysiology1 and Renal
syndrome in development characterized by Medicine2,
Alexandra
Hospital,
diffuse EEG abnormalities associated with Portsmouth,
University
positive and/or negative phenomena correlated Portsmouth3, UK).
with transient or recurring motor,cognitive or behavioural disturbances. MSNE is now included important feature of advanced chronic kidney in the ILAE classification of electroclinical disease. The pathophysiology of ‘uraemic neuropathy’ remains ill understood. Measures of axon excitability have implied that chronic diagnostic workup and suggest an underlying depolarisation, secondary to hyperkalaemia, may cause such as the presence of a genetic syndrome be the major pathological factor. The ability to reduce potassium levels with dialysis is however, short lived and a more prolonged normalisation of the associated depolarisation may be required (Ref). receiving a living-related renal transplant. Testing was performed 8 months, and 1 day pre-transplant and at 1 day, and 3 months post-transplantation. 8 months prior to transplantation peripheral nerve excitability was significantly diminished, with threshold hyperpolarising stimuli (‘fanning-in’) (p<0.005) and reduced sub- and superexcitability in the recovery cycle (p<0.02). These abnormalities worsened up until transplantation. marked recovery towards normal. This was too rapid to be explained by changes in neuronal cytostructure or remyelination. By three months post-transplantation all measures of axonal excitability had normalised. The neuropathy symptom score had improved and there was no further deterioration in ‘routine’ nerve conduction studies. These findings show ‘proof of principle’ that decreasing the amount of hyperkalaemia related depolarisation improves nerve membrane function with a potential reversal of neuropathy. Ref: Krishnan et al. Brain 2005;128:2164-74

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