EEG and FMRI coregistration to investigate the cortical oscillatory activities during finger movement.

Electroencephalography combined with functional magnetic resonance imaging (EEG-fMRI) may be used to identify blood oxygenation level dependent (BOLD) signal changes associated with physiological and pathological EEG event. In this study we used EEG-fMRI to determine the possible correlation between topographical movement-related EEG changes in brain oscillatory activity recorded from EEG electrodes over the scalp and fMRI-BOLD cortical responses in motor areas during finger movement. Thirty-two channels of EEG were recorded in 9 subjects during eyes-open condition inside a 1.5 T magnetic resonance (MR) scanner using a MR-compatible EEG recording system. Off-line MRI artifact subtraction software was applied to obtain continuous EEG data during fMRI acquisition. For EEG data analysis we used the event-related-synchronization/desynchronization (ERS/ERD) approach to investigate where movement-related decreases in alpha and beta power are located. For image statistical analysis we used a general linear model (GLM) approach. There was a significant correlation between the positive-negative ratio of BOLD signal peaks and ERD values in the electrodes over the region of activation. We conclude that combined EEG-fMRI may be used to investigate movement-related oscillations of the human brain inside an MRI scanner and the movement-related changes in the EMG or EEG signals are useful to identify the brain activation sources responsible for BOLD-signal changes.

Evaluation of botulinum toxin therapy of spastic equinus in paediatric patients with cerebral palsy.

OBJECTIVE: To develop a clinical and instrumental protocol to assess the postural and dynamic effects following treatment with botulinum neurotoxin A in children with cerebral palsy affected by spastic equinus. DESIGN: Open study, in which every patient served as his or her own control. PATIENTS: Ten sequential children with cerebral palsy and spastic dynamic equinus foot. METHODS: Botulinum neurotoxin A was injected in the gastrocnemius, soleus and tibialis posterior muscles. The main measures were: pedobarometry, dynamic surface electromyography, video gait analysis scale, and the modified Ashworth Scale. RESULTS: After treatment with botulinum neurotoxin A, pedobarometric evaluation revealed a significant change in all parameters, including a decrease in the modified Ashworth Scale and an increase in the range of motion. All children showed significant improvement in initial foot contact, as documented by the video gait analysis scale. The calf muscle electromyography pattern showed a decrease in co-contraction during gait in all children. These modifications were statistically significant for all parameters considered (p < 0.05). CONCLUSION: This pilot study suggests that dynamic electromyography and pedobarometry are simple to use and provide useful data; this protocol could be preferable in young and uncooperative children in order to monitor rehabilitation treatments.

Changes in cerebral activity after decreased upper-limb hypertonus: an EMG-fMRI study.

OBJECTIVE: Whereas several studies have used functional magnetic resonance imaging (fMRI) to investigate motor recovery, whether therapy to decrease post-stroke hypertonus alters central motor patterns remains unclear. In this study, we used continuous electromyography (EMG)-fMRI to investigate possible changes in movement-related brain activation in patients receiving Botulinum toxin (BoNT-A) for hand-muscle hypertonus after chronic stroke. METHODS: We studied eight stroke patients all of whom had hemiparesis and associated upper-limb hypertonus. All patients underwent an fMRI-EMG recording and clinical-neurological assessment before BoNT-A and 5 weeks thereafter. The handgrip motor task during imaging was fixed across both patients and controls. The movements were metronome paced, movement amplitude and force were controlled with a plastic orthosis, dynamometer and EMG recording. An age-matched control group was recruited from among healthy volunteers underwent the same fMRI-EMG recording. RESULTS: Before BoNT-A, while patients moved the paretic hand, fMRI detected wide bilateral activation in the sensorymotor areas (SM1), in the supplementary motor area (SMA) and cerebellum. After BoNT-A blood oxygenation level-dependent (BOLD) activation decreased in ipsilateral and contralateral motor areas and became more lateralized. BOLD activation decreased also in ipsilateral cerebellar regions and in the SMA. CONCLUSION: Changes in peripheral upper-limb hypertonus after BoNT-A were associated to an improvement in active movements and more lateralized and focalized activation of motor areas. The clinical and EMG-fMRI coregistration technique we used to study hand-muscle hypertonus in patients receiving BoNT-A after chronic stroke should be useful in future studies seeking improved strategies for post-stroke neurorehabilitation.