Rationale: Motor neuron disease (MND) and seizure disorders are typically considered unrelated, as their etiologies differ. MND is characterized by selective motor neuron degeneration, while seizures are associated with cortical hyperexcitability. However, in a tertiary referral center for motor neuron diseases (MND), we have observed a spectrum of seizure activity in MND patients, ranging from focal seizures to status epilepticus. This observation prompted an investigation into the potential link between MND and seizure disorders.
Methods: We conducted a retrospective review of the HY-MND registry, covering the period from October 2020 to June 2024. The registry included 819 patients initially diagnosed with motor neuron spectrum disorders. Using the hospital’s medical records database, we identified patients with KCD-10 codes for seizures (R56), epilepsy (G40), and status epilepticus (G41). A thorough chart review was performed for MND patients who were diagnosed with these seizure disorders.
Results: Out of the 819 patients in the registry, 15 patients (1.83%) were diagnosed with seizure disorders, including codes R56 (seizure), G40 (epilepsy), and G41 (status epilepticus). The semiology of seizures ranged from focal awareness seizures to status epilepticus. Most cases occurred in patients with advanced-stage ALS, often associated with the use of tracheostomy and mechanical ventilation. In many instances, seizures were linked to complications such as infection (e.g., pneumonia) and anoxic brain damage. Additionally, distinguishing between fasciculations and focal seizures was challenging in some cases.
Conclusions:
The pathological relationship between MND and seizure disorder is known to be low, as in previous reports. Our findings align with this, as most seizures in MND patients appeared to be secondary to other factors, such as anoxic brain injury and infection, rather than directly related to ALS pathology. In addition, focal seizures are very rare in ALS patients with motor weakness and may often be overlooked. Therefore, careful monitoring through regular examinations and electroencephalogram is required to ensure early detection and appropriate management.
Funding: the research fund of Hanyang University (HY-202300000003521) and National Research Foundation of Korea (NRF) grants funded by the Korean Government (MSIT) (RS-2022-00166074).