Delta-alpha ratio correlates with level of recovery after neurorehabilitation in patients with acquired brain injury
To explore the relationship between three QEEG global indexes and their association with functional outcome after neurorehabilitation in non-acute acquired brain injury (ABI) patients (traumatic brain injury and stroke).
Twenty-one adult ABI patients in post-acute phase were studied. Delta-alpha ratio (DAR), Power Ratio Index (PRI) and Mean Brain Symmetry Index (mBSI) were calculated from resting-state EEG taken at admission. These indexes and other clinical variables were correlated with functional recovery achieved after six months of neurorehabilitation.
DAR showed the highest strength of association with the functional outcome measure (rho=-0.65, P=0.002). The other QEEG indexes and clinical variables showed modest non-significant correlations. A posteriori group analysis showed higher DAR in patients with poor recovery as compared to good recovery patients.
Functional recovery after neurorehabilitation appears to be associated with a number of clinical and neurophysiological variables. Among the latter, the ratio between delta and alpha may play a significant role in predicting and monitoring functional rehabilitation outcome.
Neurophysiological assessment of ABI patients may be an important tool in monitoring and predicting outcomes after neurorehabilitation.
Available from: Michel J.A.M. van Putten
- "Alpha-to-delta ratio: The alpha-to-delta ratio (ADR) [13,18-20] was calculated as the power ratio between the alpha (8 to 13 Hz) and delta frequency band (0.5 to 4 Hz). To calculate this power ratio, a power spectral density was estimated by using Welch’s averaged periodogram method by using a Hamming window with a length of 2 seconds, resulting in a spectral-density estimation with a resolution of 0.5 Hz. "
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ABSTRACT: Electroencephalogram (EEG) monitoring in patients treated with therapeutic hypothermia after cardiac arrest may assist in early outcome prediction. Quantitative EEG (qEEG) analysis can reduce the time needed to review long-term EEG, and makes the analysis more objective. In this study we evaluated the predictive value of qEEG analysis for neurological outcome in postanoxic patients.
In total, 109 patients admitted to the ICU for therapeutic hypothermia after cardiac arrest were included, divided over a training and a test set. Continuous EEG was recorded during the first 5 days or until ICU discharge. Neurological outcomes were based on the best achieved Cerebral Performance Category (CPC) score within six months. Of the training set 27 out of 56 patients (48%) and 26 out of 53 patients (49%) of the test set achieved good outcome (CPC 1--2). In all patients a five minute epoch was selected each hour, and five qEEG features were extracted. We introduced the Cerebral Recovery Index (CRI), which combines these features into a single number.
At 24 hours after cardiac arrest, a CRI < 0.29 was always associated with poor neurological outcome, with a sensitivity of 0.55 (95% Confidence interval (CI): 0.32--0.76) at a specificity of 1.00 (CI: 0.86--1.00) in the test set. This results in a positive predictive value (PPV) of 1.00 (CI: 0.73--1.00) and a negative predictive value (NPV) of 0.71 (CI: 0.53--0.85). At the same time point a CRI >0.69 predicted good outcome, with a sensitivity of 0.25 (CI: 0.10--0.14) at a specificity of 1.00 (CI: 0.85--1.00) in the test set, and a corresponding NPV of 1.00 (CI: 0.54--1.00) and a PPV of 0.55 (CI: 0.38--0.70).
We introduced a combination of qEEG measures expressed in a single number, the CRI, which can assist in prediction of both poor and good outcome in postanoxic patients, within 24 hours after cardiac arrest.
Critical care (London, England) 10/2013; 17(5):R252. DOI:10.1186/cc13078 · 4.48 Impact Factor
Available from: Umberto Leon-Dominguez
- "Details on the exact EEG analysis procedure are given elsewhere  . "
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ABSTRACT: The design of neurorehabilitation therapy to treat subjects with altered consciousness provides opportunities and challenges to professionals involved with the care for these severely ill patients. While there is an increased interest in determining methods to restore consciousness in these patients, the process is complex and challenging, due in part to the diverse aetiology of these states of consciousness, and also to the intricate cerebral connectivity involved in their treatment. The present case study examines a patient who showed signs of emergence from the vegetative state after neurorehabilitation using The Combined Method Therapy (CMT). In this case, neurorehabilitation therapy was applied simultaneously with pharmacological treatment, stimulation, and neuroimaging techniques to help adjust drug dosage. The results of this study suggest that this combined approach to treatment promoted connectivity among posterior and anterior cortical regions aiding emergence from the vegetative state.
Current pharmaceutical design 09/2013; 20(26). DOI:10.2174/13816128113196660651 · 3.45 Impact Factor
Available from: Michela Balconi
- "Research on the resting EEG has found lower magnitudes with higher frequencies for patients in MC compared to patients with severe neurocognitive but intact consciousness. Similarly the delta-alpha ratio correlates with the level of recovery after neurorehabilitation (Leon-Carrion et al., 2009). As the alpha rhythm (8-12 Hz) is considered to be strongly related to attention and alertness, differential responses in the alpha range to deviant stimuli can be expected. "
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ABSTRACT: Disorders of consciousness were amply studied in the recent years. At this regards new methodologies and technologies were applied to explore the diagnostic and prognostic criteria that may be applied to the patients. Specifically electrophysiological measures were used to verify the degree of awareness and responsiveness in coma, vegetative states (VS), minimal consciousness state (MC), and locked-in syndrome (LI). Recently, ERPs (event-related potentials) were adopted to integrate the classical neuroimaging measures. Between the others, MMN (mismatch negativity) and P300 deflections were found to represent a consistent index of the present state of consciousness and to be predictive of successive modifications of this state. Also frequency-based EEG measures, such as brain oscillations, were revealed to be relevant marker of consciousness and awareness, able to predict the future evolution of pathology.
Neuropsychological Trends 11/2011; 10(1). · 0.15 Impact Factor
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