Review of Applications of Near-Infrared Spectroscopy in Two Rare Disorders with Executive and Neurological Dysfunction: UCD and PKU

Abstract

Studying rare diseases, particularly those with neurological dysfunction, is a challenge to researchers and healthcare professionals due to their complexity and small population with geographical dispersion. Universal and standardized biomarkers generated by tools such as functional neuroimaging have been forged to collect baseline data as well as treatment effects. However, the cost and heavily infrastructural requirement of those technologies have substantially limited their availability. Thus, developing non-invasive, portable, and inexpensive modalities has become a major focus for both researchers and clinicians. When considering neurological disorders and diseases with executive dysfunction, EEG is the most convenient tool to obtain biomarkers which can correlate the objective severity and clinical observation of these conditions. However, studies have also shown that EEG biomarkers and clinical observations alone are not sensitive enough since not all the patients present classical phenotypical features or EEG evidence of dysfunction. This article reviews disorders, including two rare disorders with neurological dysfunction and the usefulness of functional near-infrared spectroscopy (fNIRS) as a non-invasive optical modality to obtain hemodynamic biomarkers of diseases and for screening and monitoring the disease.

Are asymptomatic carriers of OTC deficiency always asymptomatic? A multicentric retrospective study of risk using the UCDC longitudinal study database

“…Application of functional near‐infrared spectroscopy (fNIRS), fMRI, MRI and DTI, and 1 H MRS modalities on proband and her daughter were as described before (Gropman et al., 2008 , 2010 ; Gropman, Prust, et al., 2013 ; Gropman, Shattuck, et al., 2013 ; Khaksari et al., 2022 ; Sprouse et al., 2014 ). An unaffected age‐matched normal female was used as control for the proband.…”

“…The proband was subsequently determined to be carrier of the same OTC variant as her daughter. Both proband and her daughter participated in the multimodal neuroimaging protocol and fNIRS testing (Figure 1 ) at Georgetown University and Children's National Hospital, respectively, as described before (Gropman et al., 2008 , 2010 ; Gropman, Prust, et al., 2013 ; Gropman, Shattuck, et al., 2013 ; Khaksari et al., 2022 ; Sprouse et al., 2014 ). Both individuals were found to have elevated glutamine, low myoinositol, and low choline on 1 H MRS (Figure 1e ).…”

Mitochondrial disorders: Emerging paradigms and the road ahead to personalized medicine

“…In “ Applications of near-infrared spectroscopy in epilepsy, with a focus on mitochondrial disorders” [ 6 ], Khaksari et al. follow Alves and Whitehead to introduce another imaging modality that is making its way more and more into the research realm of rare diseases [ 7 , 8 ]. The authors suggest the use of functional near-infrared spectroscopy (fNIRS) to identify the occurrence of epilepsy and seizures in patients with mitochondrial disorders.…”