Patients with amyotrophic lateral sclerosis (ALS) have a different functional brain network than healthy individuals, and that difference appears to be strongly associated with disability, according to new research. This finding supports previous research suggesting that monitoring a patient’s brain for changes in its neuronal network can aid in evaluating ALS disability and likely disease progression.
The study, “EEG Functional Network Topology Is Associated With Disability In Patients With Amyotrophic Lateral Sclerosis,” was published in the journal Scientific Reports.
ALS is believed to be the result of progressive impairment in a fixed set of motor connections, leading to loss of motor neuron activity and, consequently, increased disability. However, recent neuroimaging studies have questioned this belief, suggesting that the disease can spread along vast non-motor connections as well.
Importantly, previous studies have suggested that changes in the network organization of the brain occurs in ALS patients, leading to structural and functional degeneration of neuronal connections and, consequently, a re-organization of the brain’s neuronal network.
Imaging techniques have helped to elucidate the basic mechanisms related to ALS development, and its spread and progression. A recent study also supported “the use of resting-state electroencephalographic (EEG) as a potential biomarker for ALS, suggesting that a pathologic disruption of the network can be observed in early stages of the disease,” the researchers wrote.
[The brain’s functional network is essentially its wiring: how neurons connect with other neurons, because when a neuron dies, the neuron it was connected to has to re-connect to another neuron. ALS involves the loss of neurons and, as such, continual re-wiring; that forced and unusual process may be the cause of disease disability.]
In this study, researchers analyzed 21 ALS patients (mean age 66) at several stages of impairment and 16 age-matched healthy individuals, using two different EEG parameters (EEG allows monitoring of the brain’s electrical activity). They sought to investigate whether ALS is associated with changes in the neuronal network of the brain, and whether this reorganization reflected disability.
Analysis showed that, indeed, ALS patients have a different network organization compared to healthy individuals, and that this difference was significantly correlated with disability. These results also suggest that EEG analysis may be a valuable tool to help monitor and evaluate the clinical status of ALS patients.
“Previous studies have shown a direct relation between disability and disease progression,” the researchers wrote. “Interestingly, the observed correlation between network organization and disease disability suggests that it might be possible to track disease progression on the basis of EEG network analysis.”
Future studies using a larger group of ALS patients are warranted to confirm these results.