Objective Assessment of Tactile Sensitivity Using Conventional and EEG-Based Measures: A Review
Tactile sensitivity is an important component of the somatosensory system and contributes to motor control, balance, and functional independence. Impairment of tactile function is commonly observed in aging populations and in neurological or metabolic disorders, making accurate assessment clinically important. This review summarizes the neurophysiological basis of tactile perception and examines commonly used assessment methods, including mechanical tests, electrical stimulation-based techniques, and quantitative sensory testing. Their limitations are also discussed, particularly the dependence on subjective responses, limited ecological validity, and limited sensitivity to subtle sensory changes. Electroencephalography (EEG)-based measures, such as somatosensory evoked potentials (SEPs) and event-related potentials (ERPs), are also discussed as objective tools for assessing somatosensory processing. Overall, current evidence points to a critical gap in the objective and high-resolution evaluation of tactile sensitivity, highlighting the need for more precise, physiologically relevant assessment approaches.
[1] Cruz-Almeida Y, Black M, Christou E, et al., 2014, Site-Specific Differences in the Association Between Plantar Tactile Perception and Mobility Function in Older Adults. Frontiers in Aging Neuroscience, 6: 68.
[2] Perry S, 2006, Evaluation of Age-Related Plantar-Surface Insensitivity and Onset Age of Advanced Insensitivity in Older Adults Using Vibratory and Touch Sensation Tests. Neuroscience Letters, 392: 62–67.
[3] Edwards J, Vincent A, Cheng H, et al., 2008, Diabetic Neuropathy: Mechanisms to Management. Pharmacology & Therapeutics, 120: 1–34.
[4] Feldman E, Callaghan B, Pop-Busui R, et al., 2019, Diabetic Neuropathy. Nature Reviews Disease Primers, 5(1): 41.
[5] Shaffer S, Harrison A, 2007, Aging of the Somatosensory System: A Translational Perspective. Physical Therapy, 87: 193–207.
[6] Perkins B, Orszag A, Ngo M, et al., 2010, Prediction of Incident Diabetic Neuropathy Using the Monofilament Examination: A 4-Year Prospective Study. Diabetes Care, 33(7): 1549–1554.
[7] Dros J, Wewerinke A, Bindels P, et al., 2009, Accuracy of Monofilament Testing to Diagnose Peripheral Neuropathy: A Systematic Review. Annals of Family Medicine, 7: 555–558.
[8] Feng Y, Schlösser F, Sumpio B, 2009, The Semmes Weinstein Monofilament Examination as a Screening Tool for Diabetic Peripheral Neuropathy. Journal of Vascular Surgery, 50: 675–682.e1.
[9] Kurozawa Y, Hosoda T, Nasu Y, 2010, Current Perception Threshold for Assessment of the Neurological Components of Hand-Arm Vibration Syndrome: A Review. Yonago Acta Medica, 53: 59–64.
[10] Förster J, Vardiero G, Nierhaus T, et al., 2025, ERP Responses Reveal Different Neural Mechanisms for Perception of Electrical and Tactile Stimuli. Consciousness and Cognition, 135: 103935.
[11] Poornima S, Ali S, Balaji P, et al., 2013, Median Nerve Somatosensory Evoked Potentials in Medical Students: Normative Data. Advanced Biomedical Research, 2: 56.
[12] Polich J, 2007, Updating P300: An Integrative Theory of P3a and P3b. Clinical Neurophysiology, 118: 2128–2148.
[13] Lesser R, Koehle R, Lueders H, 1979, Effect of Stimulus Intensity on Short Latency Somatosensory Evoked Potentials. Electroencephalography and Clinical Neurophysiology, 47: 377–382.
[14] Abraira V, Ginty D, 2013, The Sensory Neurons of Touch. Neuron, 79: 618–639.
[15] Johnson K, 2001, The Roles and Functions of Cutaneous Mechanoreceptors. Current Opinion in Neurobiology, 11: 455–461.
[16] Johansson R, Flanagan J, 2009, Coding and Use of Tactile Signals from the Fingertips in Object Manipulation Tasks. Nature Reviews Neuroscience, 10: 345–359.
[17] Chong P, Cros D, 2004, Technology Literature Review: Quantitative Sensory Testing. Muscle & Nerve, 29: 734–747.
[18] Rolke R, Baron R, Maier C, et al., 2006, Quantitative Sensory Testing in the German Research Network on Neuropathic Pain (DFNS): Standardized Protocol and Reference Values. Pain, 123: 231–243.
[19] Tong J, Mao O, Goldreich D, 2013, Two-Point Orientation Discrimination Versus the Traditional Two-Point Test for Tactile Spatial Acuity Assessment. Frontiers in Human Neuroscience, 7: 579.
[20] Cruccu G, Aminoff M, Curio G, et al., 2008, Recommendations for the Clinical Use of Somatosensory-Evoked Potentials. Clinical Neurophysiology, 119(8): 1705–1719.
[21] Kida T, Nishihira Y, Hatta A, et al., 2003, Somatosensory N250 and P300 During Discrimination Tasks. International Journal of Psychophysiology, 48(3): 275–283.
[22] Soininen K, Järvilehto T, 1983, Somatosensory Evoked Potentials Associated with Tactile Stimulation at Detection Threshold in Man. Electroencephalography and Clinical Neurophysiology, 56: 494–500.
[23] Wühle A, Mertiens L, Rüter J, et al., 2010, Cortical Processing of Near-Threshold Tactile Stimuli: An MEG Study. Psychophysiology, 47: 523–534.
[24] Wühle A, Preissl H, Braun C, 2011, Cortical Processing of Near-Threshold Tactile Stimuli in a Paired-Stimulus Paradigm: An MEG Study. European Journal of Neuroscience, 34: 641–651.
