ABSTRACT: High frequency (30–70Hz) gamma band oscillations in the human electro-encephalogram (EEG) are thought to reflect perceptual
and cognitive processes. It is therefore interesting to study these measures in cognitive impairment and dementia. To evaluate
gamma band oscillations as a diagnostic biomarker in Alzheimer’s disease (AD) and mild cognitive impairment (MCI), 15 psychoactive
drug naïve AD patients, 20 MCI patients and 20 healthy controls participated in this study. Gamma band power (GBP) was measured
in four conditions viz. resting state, music listening, story listening and visual stimulation. To evaluate test–retest reliability
(TRR), subjects underwent a similar assessment one week after the first. The overall TRR was high. Elevated GBP was observed
in AD when compared to MCI and control subjects in all conditions. The results suggest that elevated GBP is a reproducible
and sensitive measure for cognitive dysfunction in AD in comparison with MCI and controls.
Acta Neurovegetativa 04/2012; 115(9):1301-1311. · 2.73 Impact Factor
ABSTRACT: The 40-Hz steady state response (SSR) reflects early sensory processing and can be measured with electroencephalography (EEG). The current study compared the 40-Hz SSR in groups consisting of mild Alzheimer's disease patients (AD) (n=15), subjects with mild cognitive impairment (MCI) (n=20) and healthy elderly control subjects (n=20). All participants were naïve for psychoactive drugs. Auditory click trains at a frequency of 40-Hz evoked the 40-Hz SSR. To evaluate test-retest reliability (TRR), subjects underwent a similar assessment 1 week after the first. The results showed a high TRR and a significant increase of 40-Hz SSR power in the AD group compared to MCI and controls. Furthermore a moderate correlation between 40-Hz SSR power and cognitive performance as measured by ADAS-cog was shown. The results suggest that 40-Hz SSR might be an interesting candidate marker of disease progression.
Neurobiology of aging 03/2009; 32(1):24-30. · 5.94 Impact Factor
ABSTRACT: The ictal bradycardia syndrome is an uncommon diagnosis in which bradycardia is accompanied by simultaneous epileptic discharges in the EEG. We describe a patient who was referred to the emergency ward because of syncope. Ictal semeiology and EEG-EG findings are discussed and compared with those published in the literature. Therapeutic options are discussed in relation with those published in the literature. The ictal bradycardia syndrome is probably underdiagnosed, while its recognition is of utmost importance because of potential life threatening complications such as asystole. Up to now, its aetiology is poorly understood, its ictal semeiology is often described insufficiently and its therapy is still discussed.
Acta neurologica Belgica 04/2007; 107(1):22-5. · 0.54 Impact Factor
ABSTRACT: To evaluate feasibility and utility of the soleus H-reflex and tibialis anterior flexor reflex (FR) in identifying spinal cord neuronal response to intrathecal baclofen (ITB) in children with severe spastic cerebral palsy.
During a randomized, double-blind, placebo-controlled dose-escalation test treatment, maximum H amplitude/maximum M amplitude (H/M ratio) and FR parameters were bilaterally recorded at baseline and 2-3 h after intrathecal bolus administration of placebo and increasing doses of baclofen until both an improvement in the individual treatment goal(s) and a one-point reduction on the Ashworth scale were observed.
Electrophysiological data of 14 children were studied. The H-reflex was feasible in 13 children, the FR threshold area in 9 and the FR, elicited with supramaximal stimulation, in only one child. After ITB, the H/M ratio significantly decreased (left: 0.67+/-0.47 to 0.15+/-0.18, P=0.005; right: 0.55+/-0.32 to 0.14+/-0.19, P=0.002) without placebo effect. FR threshold area after ITB, only decreased significantly in children not taking oral baclofen (left: 146+/-53 to 41+/-54 mV ms, P=0.000; right: 156+/-80 to 66+/-48 mV ms, P=0.002).
This is the first randomized, double-blind, placebo-controlled dose-escalation study in spastic children demonstrating the soleus H-reflex to be a feasible and objective measure to quantify the decreasing motoneuron excitability in response to ITB bolus administration. Only in children not taking oral baclofen, FR threshold area can also be used as an objective outcome measure, yet feasibility is limited.
We suggest introducing the H-reflex as the electrophysiological gold standard for the evaluation of the effect of ITB in spastic children.
Clinical Neurophysiology 08/2006; 117(7):1508-17. · 3.41 Impact Factor