Bridging Temporal and Cepstral Hemodynamic Intelligence: An Adaptive Multi-Domain Feature Fusion Framework for Multi-Class fNIRS Brain–Computer Interfaces


Saad Bin Abdul Ghaffar M. S. B. A., Ertunç H. M., Kaplan K., Küçük K., Yahya K., Khan S. A.

SENSORS, cilt.26, sa.20, ss.1-51, 2026 (Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 26 Sayı: 20
  • Basım Tarihi: 2026
  • Doi Numarası: 10.3390/s26206427
  • Dergi Adı: SENSORS
  • Derginin Tarandığı İndeksler: Academic Search Ultimate (EBSCO), Biomedical Reference Collection: Corporate Edition (EBSCO), Health Research Premium Collection (ProQuest), Scopus, Compendex, EMBASE, INSPEC, MEDLINE, Directory of Open Access Journals
  • Sayfa Sayıları: ss.1-51
  • Kocaeli Üniversitesi Adresli: Evet

Özet

Reliable four-class decoding remains challenging for functional near-infrared spectroscopy (fNIRS) brain–computer interfaces (BCIs), because a single feature domain captures only part of the hemodynamic response. This study proposes an Adaptive Multi-Domain Feature Fusion (AMFF) framework that combines six temporal hemodynamic descriptors with ten fNIRS-adapted Mel-frequency cepstral coefficients (MFCCs) and learns sample-dependent weights for the two domains before classification with a multilayer perceptron. The framework was evaluated on an open-access dataset of 29 participants performing left- and right-hand motor imagery, mental arithmetic, and rest, using subject-independent leave-one-subject-out cross-validation. AMFF achieves a mean accuracy of 95.6%, with precision, recall, and F1-score of 94.6%, 95.9%, and 95.3%, respectively, outperforming temporal only (90.7%), cepstral-only (95.0%), and direct concatenation (95.2%) representations, with a modest but consistent gain over direct concatenation across participants. Friedman and Holm-corrected Wilcoxon signed-rank tests confirmed significant differences for all four metrics; AMFF exceeded static concatenation for every participant, although by a small margin (0.2–0.7 percentage points). Most of the gain over temporal descriptors therefore comes from the cepstral domain, with adaptive weighting adding a small but consistent refinement. MFCC parameter-sensitivity, coefficient-ablation, and descriptor-ablation analyses further characterize the contribution of each domain.