The potential of using Electro-Encephalo-Gram (EEG) data as a biometric identifier is studied. Th... more The potential of using Electro-Encephalo-Gram (EEG) data as a biometric identifier is studied. This is the first study that assesses looming stimuli for the creation of biometrically useful Visual Evoked Potentials (VEP), i.e. EEG responses due to visual stimuli. A novel method for the detection of VEP responses with minimal expert interaction is introduced. The EEG data, segmented based on the VEP, are used to create a reliable feature vector. In contrast to previous studies, we provide a publicly available evaluation dataset based on infants which is therefore not biased due to unhealthy individuals. Only data from the occipital cortex are used (i.e. about 3 of the many possible electrode positions in the scalp), making the potential EEG biometric capture devices relatively simpler.
Developmental Medicine & Child Neurology, 1991
In order to examine the possibility that children with cerebral palsy (CP) find abstract tasks, s... more In order to examine the possibility that children with cerebral palsy (CP) find abstract tasks, such as extending the arm as much as possible, more difficult than concrete tasks, such as reaching to grasp an object, nine hemiparetic children with CP and 12 nursery-school children were tested with both a concrete and an abstract task. The children with CP achieved a significantly larger range of movement in the concrete task, whereas the nursery-school children showed no difference between tasks. Thus the CP children's poorer performance on the abstract task did not fully reflect their movement capability. This means that conventional neurological measurements of limb function in cerebral palsy, which mainly use abstract tasks or passive movements, will give an incomplete picture of the child's action capability.
Electroencephalogram (EEG) was used to investigate brain electrical activity of full-term and pre... more Electroencephalogram (EEG) was used to investigate brain electrical activity of full-term and preterm infants at 4 and 12 months of age as a functional response mechanism to structured optic flow and random visual motion. EEG data were recorded with an array of 128-channel sensors. Visual evoked potentials (VEPs) and temporal spectral evolution (TSE, time-dependent amplitude changes) were analysed. VEP results showed a significant improvement in full-term infants' latencies with age for forwards and reversed optic flow but not random visual motion. Full-term infants at 12 months significantly differentiated between the motion conditions, with the shortest latency observed for forwards optic flow and the longest latency for random visual motion, while preterm infants did not improve their latencies with age, nor were they able to differentiate between the motion conditions at 12 months. Differences in induced activities were also observed where comparisons between TSEs of the motion conditions and a static non-flow pattern showed desynchronised theta-band activity in both full-term and preterm infants, with synchronised alpha-beta band activity observed only in the full-term infants at 12 months. Full-term infants at 12 months with a substantial amount of self-produced locomotor experience and neural maturation coupled with faster oscillating cell assemblies, rely on the perception of structured optic flow to move around efficiently in the environment. The poorer responses in the preterm infants could be related to impairment of the dorsal visual stream specialized in the processing of visual motion.
A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in re... more A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in response to high speeds of simulated forward motion. Participants were shown an optic flow pattern consisting of a virtual road with moving poles at either side of it, simulating structured forward motion at different driving speeds (25, 50, and 75 km/h) with a static control condition between each motion condition. Significant differences in N2 latencies and peak amplitudes between the three speeds of visual motion were found in parietal channels of interest P3 and P4. As motion speed increased, peak latency increased while peak amplitude decreased which might indicate that higher driving speeds are perceived as more demanding resulting in longer latencies, and as fewer neurons in the motion sensitive areas of the adult brain appear to be attuned to such high visual speeds this could explain the observed inverse relationship between speed and amplitude. In addition, significant difference...
The potential of using Electro-Encephalo-Gram (EEG) data as a biometric identifier is studied. Th... more The potential of using Electro-Encephalo-Gram (EEG) data as a biometric identifier is studied. This is the first study that assesses looming stimuli for the creation of biometrically useful Visual Evoked Potentials (VEP), i.e. EEG responses due to visual stimuli. A novel method for the detection of VEP responses with minimal expert interaction is introduced. The EEG data, segmented based on the VEP, are used to create a reliable feature vector. In contrast to previous studies, we provide a publicly available evaluation dataset based on infants which is therefore not biased due to unhealthy individuals. Only data from the occipital cortex are used (i.e. about 3 of the many possible electrode positions in the scalp), making the potential EEG biometric capture devices relatively simpler.
Developmental Medicine & Child Neurology, 1991
In order to examine the possibility that children with cerebral palsy (CP) find abstract tasks, s... more In order to examine the possibility that children with cerebral palsy (CP) find abstract tasks, such as extending the arm as much as possible, more difficult than concrete tasks, such as reaching to grasp an object, nine hemiparetic children with CP and 12 nursery-school children were tested with both a concrete and an abstract task. The children with CP achieved a significantly larger range of movement in the concrete task, whereas the nursery-school children showed no difference between tasks. Thus the CP children's poorer performance on the abstract task did not fully reflect their movement capability. This means that conventional neurological measurements of limb function in cerebral palsy, which mainly use abstract tasks or passive movements, will give an incomplete picture of the child's action capability.
Electroencephalogram (EEG) was used to investigate brain electrical activity of full-term and pre... more Electroencephalogram (EEG) was used to investigate brain electrical activity of full-term and preterm infants at 4 and 12 months of age as a functional response mechanism to structured optic flow and random visual motion. EEG data were recorded with an array of 128-channel sensors. Visual evoked potentials (VEPs) and temporal spectral evolution (TSE, time-dependent amplitude changes) were analysed. VEP results showed a significant improvement in full-term infants' latencies with age for forwards and reversed optic flow but not random visual motion. Full-term infants at 12 months significantly differentiated between the motion conditions, with the shortest latency observed for forwards optic flow and the longest latency for random visual motion, while preterm infants did not improve their latencies with age, nor were they able to differentiate between the motion conditions at 12 months. Differences in induced activities were also observed where comparisons between TSEs of the motion conditions and a static non-flow pattern showed desynchronised theta-band activity in both full-term and preterm infants, with synchronised alpha-beta band activity observed only in the full-term infants at 12 months. Full-term infants at 12 months with a substantial amount of self-produced locomotor experience and neural maturation coupled with faster oscillating cell assemblies, rely on the perception of structured optic flow to move around efficiently in the environment. The poorer responses in the preterm infants could be related to impairment of the dorsal visual stream specialized in the processing of visual motion.
A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in re... more A high-density EEG study was conducted to investigate evoked and oscillatory brain activity in response to high speeds of simulated forward motion. Participants were shown an optic flow pattern consisting of a virtual road with moving poles at either side of it, simulating structured forward motion at different driving speeds (25, 50, and 75 km/h) with a static control condition between each motion condition. Significant differences in N2 latencies and peak amplitudes between the three speeds of visual motion were found in parietal channels of interest P3 and P4. As motion speed increased, peak latency increased while peak amplitude decreased which might indicate that higher driving speeds are perceived as more demanding resulting in longer latencies, and as fewer neurons in the motion sensitive areas of the adult brain appear to be attuned to such high visual speeds this could explain the observed inverse relationship between speed and amplitude. In addition, significant difference...
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Papers by Audrey L H van der Meer