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Task-Evoked Prefrontal Hemodynamics During Cognitive Assessment in Amyotrophic Lateral Sclerosis Using fNIRS
Journal article   Open access   Peer reviewed

Task-Evoked Prefrontal Hemodynamics During Cognitive Assessment in Amyotrophic Lateral Sclerosis Using fNIRS

Alshehri Saqer, Atabek Bartu, Terry Heiman-Patterson and Hasan Ayaz
Brain sciences, v 16(8), 895
21 Aug 2026
DOI: https://doi.org/10.3390/brainsci16080895
Featured in Collection :   Research Supported by Drexel Libraries' OA Programs
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https://doi.org/10.3390/brainsci16080895View
Published, Version of Record (VoR) Open Access Discount via Drexel Libraries Read and Publish Program 2026 Open CC BY V4.0

Abstract

Cognitive ability Data collection Hemoglobin Information processing Infrared spectroscopy Prefrontal cortex Processing speed Registration Resource allocation Sensors Amyotrophic Lateral Sclerosis Hemodynamics Medical Imaging Neurodegenerative Diseases Neuroimaging Signal Processing Software Visual Perception
What are the main findings? Despite comparable behavioral performance, wearable fNIRS revealed a group-specific hemodynamic pattern in ALS: deoxygenated hemoglobin (HbR) at the left DLPFC rose progressively with task difficulty in ALS participants but remained stable in controls, with significant between-group differences at the three harder conditions. Oxygenated hemoglobin (HbO) increased with task difficulty across all prefrontal optodes in both groups, confirming robust task-evoked engagement, so the ALS-specific effect was isolated to HbR regulation at the left DLPFC rather than a general activation difference. What are the implications of the main findings? The dissociation between preserved behavioral performance and altered prefrontal hemodynamics suggests that routine behavioral measures may miss subtle cortical changes in ALS, which wearable fNIRS can reveal as an objective physiological readout during brief cognitive-motor assessment. Because fNIRS is portable, non-invasive, and tolerant of naturalistic settings, it may complement conventional clinical and behavioral tools for sensitive, repeatable monitoring of cognitive-motor function and, pending larger and longitudinal studies, potentially disease progression in ALS. Background/Objectives: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease increasingly recognized for extra-motor manifestations, including cognitive dysfunction involving frontal cortical systems. Conventional clinical assessments are primarily behavioral and may not capture subtle alterations in the neural systems that support cognitive performance. This pilot study examined whether wearable functional near-infrared spectroscopy (fNIRS) could detect task-evoked prefrontal hemodynamic differences during the King-Devick Task (KDT), a rapid oculomotor number-naming task that engages visual scanning, attention, processing speed, and verbal response production. Methods: Sixteen participants, including seven individuals with ALS and nine age-matched healthy controls (HC), completed four progressively difficult KDT conditions while prefrontal cortical activity was recorded. Results: As task difficulty increased, response times became slower across participants, while accuracy remained preserved and behavioral performance did not differ significantly between groups. Prefrontal oxygenated hemoglobin (HbO) responses increased with task difficulty across all prefrontal optodes, supporting task-evoked cortical engagement. In contrast, deoxygenated hemoglobin (HbR) responses showed a group-specific pattern in the left dorsolateral prefrontal cortex: individuals with ALS demonstrated progressively increasing HbR responses across difficulty conditions, whereas HC showed relatively stable responses, with group differences emerging at higher difficulty levels. Conclusions: These findings suggest a dissociation between preserved behavioral performance and altered prefrontal hemodynamic regulation in ALS. The observed HbR pattern may reflect differences in cortical recruitment, neurovascular coupling, oxygen extraction, vascular responsiveness, or the efficiency of cortical resource allocation during increasing cognitive-motor demands. Wearable fNIRS may therefore complement behavioral assessments by revealing task-evoked neural alterations that are not evident from performance measures alone.

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