fNIRS Approach to Pain Assessment for Non-verbal Patients

Raul Fernandez Rojas, Xu Huang, Julio Romero, Keng Liang Ou

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Citations (Scopus)


The absence of verbal communication in some patients (e.g., critically ill, suffering from advanced dementia) difficults their pain assessment due to the impossibility to self-report pain. Functional near-infrared spectroscopy (fNIRS) is a non-invasive technology that has showed promising results in assessing cortical activity in response to painful stimulation. In this study, we used fNIRS signals to predict the state of pain in humans using machine learning methods. Eighteen healthy subjects were stimulated using thermal stimuli with a thermode, while their cortical activity was recorded using fNIRS. Bag-of-words (BoW) model was used to represent each fNIRS time series. The effect of different step sizes, window lengths, and codebook sizes was investigated to improve computational cost and generalization. In addition, we explored the effect of choosing different features as neurological biomarkers in three different domains: time, frequency, and time-frequency (wavelet). Classification on the histogram representation was performed using K-nearest neighbours (K-NN). The performance is evaluated by using leave-one-out cross validation and with different nearest neighbours. The results showed that wavelet-based features produced the highest accuracy (88.33 %) to distinguish between heat and cold pain while discriminate between low and high pain. It is possible to use fNIRS to assess pain in response to four types of thermal pain. However, future research is needed for the assessment of pain in clinical settings.

Original languageEnglish
Title of host publicationNeural Information Processing - 24th International Conference, ICONIP 2017, Proceedings
EditorsDerong Liu, Shengli Xie, Yuanqing Li, El-Sayed M. El-Alfy, Dongbin Zhao
PublisherSpringer Verlag
Number of pages10
ISBN (Print)9783319700922
Publication statusPublished - 2017
Event24th International Conference on Neural Information Processing, ICONIP 2017 - Guangzhou, China
Duration: Nov 14 2017Nov 18 2017

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume10637 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other24th International Conference on Neural Information Processing, ICONIP 2017


  • Brain
  • Haemodynamic
  • Multiclass
  • Neural
  • Pain
  • Time series

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


Dive into the research topics of 'fNIRS Approach to Pain Assessment for Non-verbal Patients'. Together they form a unique fingerprint.

Cite this