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Magnetic source imaging of cortical dysfunction in amyotrophic lateral sclerosis
Robert A Boyajian1, Carlos Amo, Shirley M Otis
1Brain Research and Treatment Center, Division of Neurology, Department of Medicine, Scripps Clinic, La Jolla, California, USA.
Summary
Magnetic source imaging detected abnormal brain activity in all amyotrophic lateral sclerosis (ALS) patients, indicating widespread cortical dysfunction. This technique may reveal insights into motor disability in ALS.
Area of Science:
- Neuroscience
- Biophysics
Background:
- Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease primarily affecting motor neurons.
- Cortical involvement is increasingly recognized in ALS, but its precise nature and functional consequences remain incompletely understood.
Observation:
- Spontaneous brain activity in patients with ALS was recorded using 148-channel magnetoencephalography (MEG).
- Localized dipolar sources of focal delta-theta (1-7 Hz) discharges were investigated in patients without dementia.
- Magnetic resonance imaging (MRI) was used to define anatomic brain regions for source mapping.
Findings:
- MEG identified localized slow wave dipole sources in all seven ALS patients, but none in eight age-similar controls.
- Slow wave bursts originated from frontal, temporal, and parietal cortices, correlating with upper-extremity disability.
- A substudy revealed abnormal central processing of purposeful movement in an ALS patient with limb apraxia.
Implications:
- This study demonstrates widespread cortical dysfunction in ALS patients, even those recently diagnosed.
- Magnetoencephalography (MEG) shows promise as a tool for investigating cortical dysfunction's role in ALS motor disability.
- Findings suggest potential for MEG in understanding disease mechanisms and developing targeted therapies.
