Applications of near-infrared spectroscopy in epilepsy, with a focus on mitochondrial disorders

Mitochondrial diseases are inherited disorders that impede the mitochondria's ability to produce sufficient energy for the cells. They can affect different parts of the body, notably the brain. Neurological symptoms and epilepsy are prevalent in patients with mitochondrial disorders. The epileptogenicity of mitochondrial disorder is a complex process involving the intricate interplay between abnormal energy metabolism and neuronal activity. Several modalities have been used to detect seizures in different disorders including mitochondrial disorders. EEG serve as the gold standard for diagnosis and localization, commonly complemented by additional imaging modalities to enhance source localization. In the current work, we propose the use of functional near-infrared spectroscopy (fNIRS) to identify the occurrence of epilepsy and seizure in patients with mitochondrial disorders. fNIRS proves an advantageous imaging technique due to its portability and insensitivity to motion especially for imaging infants and children. It has added a valuable factor to our understanding of energy metabolism and neuronal activity. Its real-time monitoring with high spatial resolution supplements traditional diagnostic tools such as EEG and provides a comprehensive understanding of seizure and epileptogenesis. The utility of fNIRS extends to its ability to detect changes in Cytochrome c oxidase (CcO) which is a crucial enzyme in cellular respiration. This facet enhances our insight into the metabolic dimension of epilepsy related to mitochondrial dysfunction. By providing valuable insights into both energy metabolism and neuronal activity, fNIRS emerges as a promising imaging technique for unveiling the complexities of mitochondrial disorders and their neurological manifestations.