The influence of central neuropathic pain in paraplegic patients on performance of a motor imagery based brain computer interface

The aim of this study was to test how the presence of central neuropathic pain (CNP) influences the performance of a motor imagery based Brain Computer Interface (BCI). In this electroencephalography (EEG) based study, we tested BCI classification accuracy and analysed event related desynchronisation (ERD) in 3 groups of volunteers during imagined movements of their arms and legs. The groups comprised of nine able-bodied people, ten paraplegic patients with CNP (lower abdomen and legs) and nine paraplegic patients without CNP. We tested two types of classifiers: a 3 channel bipolar montage and classifiers based on common spatial patterns (CSPs), with varying number of channels and CSPs. Paraplegic patients with CNP achieved higher classification accuracy and had stronger ERD than paraplegic patients with no pain for all classifier configurations. Highest 2-class classification accuracy was achieved for CSP classifier covering wider cortical area: 82 ± 7% for patients with CNP, 82 ± 4% for able-bodied and 78 ± 5% for patients with no pain. Presence of CNP improves BCI classification accuracy due to stronger and more distinct ERD. Results of the study show that CNP is an important confounding factor influencing the performance of motor imagery based BCI based on ERD

Dynamic oscillatory signatures of central neuropathic pain in spinal cord injury

Central Neuropathic Pain (CNP) is believed to be accompanied by increased activation of the sensory and motor cortices. Our knowledge on this interaction is based mainly on fMRI studies, but there is little direct evidence on how these changes manifest in terms of dynamic neuronal activity. This study reports on the presence of transient EEG based measures of brain activity during motor imagery in spinal cord injured patients with CNP. We analyse dynamic EEG responses during imaginary movements of arms and legs in 3 groups of 10 volunteers each, comprising able-bodied people, paraplegic patients with CNP (lower abdomen and legs) and paraplegic patients without CNP. Paraplegic patients with CNP had increased event-related desynchronisation in the theta, alpha and beta bands (16-24 Hz) during imagination of movement of both non-painful (arms) and painful limbs (legs). Compared to patients with CNP, paraplegics with no pain showed a much reduced power in relaxed state and reduced event-related desynchronisation during imagination of movement. Understanding these complex dynamic, frequency-specific activations in CNP in the absence of nociceptive stimuli could inform the design of interventional therapies for patients suffering from CNP and possibly further understanding of the mechanisms involved

Identification of time-frequency EEG features modulated by force direction in arm isometric exertions

Electroencephalographic (EEG) activity associated with human motor tasks has been studied in time domain and time-frequency representations. Various classification and decoding techniques have been used to extract movement or motor task parameters from EEG such as direction of an isometrically exerted force. Identification of time and time-frequency regions that contain the highest directional information can considerably enhance the efficiency of decoding and classification algorithms. In this paper we have addressed this issue for directional arm isometric exertions to 4 different directions in horizontal plane. We have used the non-parametric Permutational ANOVA to identify time-frequency regions capturing the highest level of inter-group variance as a measure of directional information. There are information-rich regions in delta, theta, alpha, and beta bands after corresponding visual cues. Parietal regions show higher directional information during planning compared to execution. The results can be used for pattern classification and decoding of motor parameters in Brain-Computer-Interfacing (BCI) and BCI-rehabilitation

Motor imagery in spinal cord injury with neuropathic pain

Large number of chronic Spinal Cord Injured (SCI) patients suffer from Central Neuropathic (CNP) pain that modifies both spontaneous EEG and Event related EEG responses. The aim of this paper was to analyze on a group level, using clustering approach, differences in EEG signatures between two Groups: the able-bodied persons and SCI patients with CNP during a motor imagination task. Results of this study showed that compared to the able-bodied, SCI patients with pain have lower ERS/ERD in the central and the centro/parietal areas of the motor cortex, which correspond to the paralyzed part of the body and higher event-related synchronization/desynchronisation (ERS/ERD) in the rest of the cortex, including frontal areas, remaining areas of the sensory-motor cortex and the occipital area. Significant differences in Power Spectral Density (PSD) between two Groups were found in 20-30 Hz range, possibly related to the baseline EEG rather then to the mental task

Reduced activation at the cortical level following neurofeedback treatment is associated with reduction in central neuropathic pain intensity

No abstract available

Reduced activation at the cortical level following neurofeedback treatment is associated with reduction in central neuropathic pain intensity

No abstract available