Improving neurophysiological biomarkers for functional myoclonic movements.

INTRODUCTION: Differentiating between functional jerks (FJ) and organic myoclonus can be challenging. At present, the only advanced diagnostic biomarker to support FJ is the Bereitschaftspotential (BP). However, its sensitivity is limited and its evaluation subjective. Recently, event related desynchronisation in the broad beta range (13-45 Hz) prior to functional generalised axial (propriospinal) myoclonus was reported as a possible complementary diagnostic marker for FJ. Here we study the value of ERD together with a quantified BP in clinical practice. METHODS: Twenty-nine patients with FJ and 16 patients with cortical myoclonus (CM) were included. Jerk-locked back-averaging for determination of the 'classical' and quantified BP, and time-frequency decomposition for the event related desynchronisation (ERD) were performed. Diagnostic gain, sensitivity and specificity were obtained for individual and combined techniques. RESULTS: We detected a classical BP in 14/29, a quantitative BP in 15/29 and an ERD in 18/29 patients. At group level we demonstrate that ERD in the broad beta band preceding a jerk has significantly higher amplitude in FJ compared to CM (respectively -0.14 ± 0.13 and +0.04 ± 0.09 (p < 0.001)). Adding ERD to the classical BP achieved an additional diagnostic gain of 53%. Furthermore, when combining ERD with quantified and classical BP, an additional diagnostic gain of 71% was achieved without loss of specificity. CONCLUSION: Based on the current findings we propose to the use of combined beta ERD assessment and quantitative BP analyses in patients with a clinical suspicion for all types of FJ with a negative classical BP

Survey in expert clinicians on validity of automated calculation of optimal cerebral perfusion pressure

BACKGROUND: Optimal cerebral perfusion pressure (CPPopt) targeting in traumatic brain injury (TBI) patients constitutes an active and controversial area of research. It has been suggested that an autoregulation guided CPP therapy may improve TBI outcome. Prerequisites of a CPPopt intervention study would be objective criteria for the CPPopt detection.. This study compared the agreement between automated and visual CPPopt detection. METHODS: Twenty-five clinicians from 18 centres worldwide, familiar with brain monitoring and using dedicated software, reviewed ten 4-hour CPPopt screenshots at 48 hrs after ictus in selected TBI patients. Each screenshot displayed the trends of cerebral perfusion pressure (CPP), intracranial pressure (ICP), cerebrovascular pressure reactivity (PRx) as well as the ‘CPP-optimal’ curve and its associated value (automated CPPopt). The main objective was to evaluate the agreement between expert clinicians as well as the agreement between the clinicians and automated CPPopt. RESULTS: Twenty-two clinicians responded to our call (88%). Three screenshots were judged as ‘CPPopt not determinable’ by > 45% of the clinicians. For the whole group, the consensus between automated CPPopt and clinicians’ visual CPPopt was high. Three clinicians were identified as outliers. All clinicians recommended to modify CPP when patients differed > ± 5 mmHg from their CPPopt. The inter-observer consensus was highest in cases with current CPP below the optimal value. CONCLUSIONS: The overall agreement between automated CPPopt and visual CPPopt identified by autoregulation experts was high, except for those cases when the curve was deemed by the clinicians not reliable enough to yield a trustworthy CPPopt

Increased serum neuron specific enolase concentrations in patients with hyperglycemic cortical ischemic stroke

A detrimental effect of hyperglycemia in ischemic brain has been demonstrated in laboratory experiments and it has been found that hyperglycemia in ischemic stroke is a predictor of poor outcome. We determined serum neuron specific enolase (NSE) concentrations in 41 consecutive patients with a cerebral hemispheric stroke between 12 and 24 h after stroke onset. In cortical ischemic strokes complicated by hyperglycemia (blood glucose concentration > 7 mmol/l) we found significantly higher NSE levels than in normoglycemic patients. In lacunar ischemic strokes NSE levels were not significantly different between normoglycemic and hyperglycemic patients. Our findings support the concept that hyperglycemia during acute cortical ischemic stroke is associated with enhanced neuronal cell death. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved

Predicting outcome from coma:man-in-the-barrel syndrome as potential pitfall

The Glasgow coma scale motor score is often used in predicting outcome after hypoxic ischemic coma. Judicious care should be exerted when using this variable in predicting outcome in patients with coma following hypotension since borderzone infarction can obscure the clinical picture. We describe a patient who underwent skull base surgery for a schwannoma of the left facial nerve. The operation, which lasted for 10 h, was conducted under controlled hypotension. After the intervention the patient remained comatose with absent arm movements upon painful stimuli. An absent motor score usually carries a poor prognosis. However, magnetic resonance inversion recovery imaging of the brain showed bilateral hyperintense lesions in the arm-hand area indicative of borderzone ischemic damage. The patient received optimal supportive care and after 17 days he regained consciousness with man-in-the-barrel syndrome', which also further improved over time. (C) 2000 Elsevier Science B.V. All rights reserved