Table 2 Summary of neurophysiological sensors used in the reviewed literature, including the anatomical location of recording sensor and the expected neurophysiological response to pain.

EDA

(↑) Skin conductance

(↓) Skin resistance

Palmar surface of index and ring fingers

^{28,34,35,36,37,38,39,40}

Palmar surface of index and middle fingers

^{29,31,32,33,98,160}

Palmar surface of two fingers

⁴¹

Abode and below second knuckle of hand

¹⁶¹

Wrist

^42,43,44,45

sEMG

(↑) Trapezious muscle activity

Upper right trapezious

^28,34,35,37

Corrugator supercilii

⁹⁸

(↑) Corrugator supercilii muscle activity

Trapezious, corrugator supercilii, and zygomaticus

^38,39,160

(↑) Zygomaticus major muscle activity

Cheek and corrugator supercilii

⁴¹

RESP

(↑) Inspiration

(↓) Breathing rate

Thorax

^34,41,98

–

^53,136

SpO₂

(↑) Oxygen saturation

–

^53,136

BP

(↑) Systolic BP

(↓) Diastolic BP

–

⁵³

ECG

(↓) HRV

(↑) HR

Right and left wrist

⁴⁶

Thorax

^{28,34,35,36,37,38,39,40,41,49,160}

–

¹³⁶

Wrist and ankle

³³

MOVE

(↓) Movement

(↓) Steps

Wrist

^43,44

SKT

(↓) Skin temperature

Wrist

^43,44

–

⁵³

Fingertip of non-dominant hand

³³

PUPIL

(↓) Pupillary diameter

Eyes

^56,136

PPG

(↑) HR or pulse rate

(↓) Blood volume pulse

(↓) Pulse transit time

Left index finger

^{40,49,52,117,161}

Wrist

^43,44,118

–

⁵³

Left ring finger

⁹⁸

Thumb of non-dominant hand

³³

EEG

N2 and P2 activation

(↓) Alpha

(↓) Beta

(↑) Delta

(↑) Theta

(↑) Gamma

Full head

^{61,62,72,83,84,94,103,129,161}

Head circumference

^{59,63,64,92,93}

fNIRS

(↓) HbR

(↑) HbO

Somatosensory area

^66,69,85,86

Prefrontal and somatosensory area

⁹⁶

Prefrontal area

^70,71