TY  - JOUR
A1  - Erlbeck, Helena
A1  - Mochty, Ursula
A1  - Kübler, Andrea
A1  - Real, Ruben G. L.
T1  - Circadian course of the P300 ERP in patients with amyotrophic lateral sclerosis - implications for brain-computer interfaces (BCI)
JF  - BMC Neurology
N2  - Background:
Accidents or neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) can lead to progressing, extensive, and complete paralysis leaving patients aware but unable to communicate (locked-in state). Brain-computer interfaces (BCI) based on electroencephalography represent an important approach to establish communication with these patients. The most common BCI for communication rely on the P300, a positive deflection arising in response to rare events. To foster broader application of BCIs for restoring lost function, also for end-users with impaired vision, we explored whether there were specific time windows during the day in which a P300 driven BCI should be preferably applied.
Methods:
The present study investigated the influence of time of the day and modality (visual vs. auditory) on P300 amplitude and latency. A sample of 14 patients (end-users) with ALS and 14 healthy age matched volunteers participated in the study and P300 event-related potentials (ERP) were recorded at four different times (10, 12 am, 2, & 4 pm) during the day.
Results:
Results indicated no differences in P300 amplitudes or latencies between groups (ALS patients v. healthy participants) or time of measurement. In the auditory condition, latencies were shorter and amplitudes smaller as compared to the visual condition.
Conclusion:
Our findings suggest applicability of EEG/BCI sessions in patients with ALS throughout normal waking hours. Future studies using actual BCI systems are needed to generalize these findings with regard to BCI effectiveness/efficiency and other times of day.
KW  - brain computer interface
KW  - amyotrophic lateral sclerosis
KW  - ALS
KW  - P300
KW  - auditory
KW  - visual
KW  - BCI
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-157423
VL  - 17
IS  - 3
ER  - 
TY  - JOUR
A1  - Erlbeck, Helena
A1  - Kübler, Andrea
A1  - Kotchoubey, Boris
A1  - Veser, Sandra
T1  - Task instructions modulate the attentional mode affecting the auditory MMN and the semantic N400
JF  - Frontiers in Human Neuroscience
N2  - Event-related potentials (ERPs) have been proven to be a useful tool to complement clinical assessment and to detect residual cognitive functions in patients with disorders of consciousness. These ERPs are of ten recorded using passive or unspecific instructions. Patient data obtained this way are then compared to data from healthy participants, which are usually recorded using active instructions. The present study investigates the effect of attentive modulations and particularly the effect of activevs. passive instruction on the ERP components mismatch negativity (MMN) and N400. A sample of 18 healthy participants listened to three auditory paradigms: anoddball, aword priming, and a sentence paradigm. Each paradigm was presented three times with different instructions: ignoring auditory stimuli, passive listening, and focused attention on the auditory stimuli. After each task, the participants indicated their subjective effort. The N400 decreased from the focused task to the passive task, and was extinct in the ignore task. The MMN exhibited higher amplitudes in the focused and passive task compared to the ignore task. The data indicate an effect of attention on the supratemporal component of the MMN. Subjective effort was equally high in the passive and focused tasks but reduced in the ignore task. We conclude that passive listening during EEG recording is stressful and attenuates ERPs, which renders the interpretation of the results obtained in such conditions difficult.
KW  - ERP
KW  - priming
KW  - selective attention
KW  - event-related potentials
KW  - vigilance decrement
KW  - brain potentials
KW  - vegetative state
KW  - consciousness
KW  - component
KW  - predicts recovery
KW  - mismatch negativity
KW  - attention
KW  - instruction
KW  - N400
KW  - MMN
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115553
VL  - 8
IS  - 654
ER  -