Quantitative Sensory Testing Data Research Articles

Assessment of Trigeminal Nerve Functions by Quantitative Sensory Testing in Patients and Healthy Volunteers

Orofacial sensory dysfunction plays an important role in oral and maxillofacial surgery. Quantitative sensory testing (QST) is a psychophysical approach to evaluate thermal and mechanical somatosensation. The present human study 1) collected normative QST data in extraoral and intraoral regions, 2) analyzed effects of age, gender, and anatomical sites on QST, and 3) applied QST in 11 patients with iatrogenic inferior alveolar nerve lesions. Sixty (30 male and 30 female) healthy volunteers were tested bilaterally in the innervation areas of infraorbital, mental, and lingual nerves. Ten patients with sensory disturbances in innervation areas of the mental nerve were investigated at 1, 4, and 8 weeks after surgery. Another patient with a complete sensory loss after surgery was repetitively tested within 453 days after primary surgery (dental implant) and subsequent surgical reconstruction of the inferior alveolar nerve by autologous graft. Older subjects were significantly less sensitive than younger subjects for thermal parameters. Thermal detection thresholds in infraorbital and mental regions showed higher sensitivity in women. Sensitivity to thermal stimulation was higher in the infraorbital region than in the mental and lingual regions. QST monitored somatosensory deficits and recovery of inferior alveolar nerve functions in all patients. Age, gender, and anatomic region affect various QST parameters. QST might be useful in the diagnosis of inferior alveolar nerve disorders in patients. In dentistry, the monitoring of afferent nerve fiber functions by QST might support decisions on further interventions.

Quantitative sensory abnormalities in post-surgical cutaneous nerve injuries

Quantitative sensory testing (QST) is a psychophysical approach measuring evoked responses to standardized mechanical and thermal stimuli, whether painful or non-painful. QST may be of benefit in assessing pain mechanisms in various pathological states. Here we chose to characterize QST responses in a cohort of 10 patients with post-surgical cutaneous nerve injuries (scar neuromas) and persistent pain following surgery or injury. We included patients who had greater than 80% pain relief following subcutaneous injection of 0.5% bupivacaine. We characterized thermal (cold and warmth) detection and pain thresholds, mechanical detection and pain thresholds, mechanical pain sensitivity for pinprick stimuli, dynamic mechanical allodynia, and wind-up ratio. Prior to conducting QST at the scar neuroma, all procedures were conducted at a contralateral or non-painful control area. Comparisons between the site of pain and control were made using paired t-tests and Wilcoxon signed-rank significance tests. All statistical analysis was conducted in SAS 9.1. We found mechanical detection thresholds to be significantly higher (p < 0.05) at the painful site, and pain ratings to be significantly higher in response to a 512 mN pin (p < 0.05) at the painful site. This suggests diminished mechanical detection but increased sensitivity to pain caused by pressure in the painful area. These results provide the first QST data for painful scar neuromas. Further work to verify these results in a larger cohort would be of benefit. We are currently characterizing the QST response to a therapeutic intervention and furthermore determining whether QST values predict and track therapeutic responsiveness.

Reference values for quantitative sensory testing in children and adolescents: Developmental and gender differences of somatosensory perception

The Quantitative Sensory Testing (QST) protocol of the German research network on neuropathic pain (DFNS) encompassing all somatosensory modalities assesses the functioning of different nerve fibers and of central pathways. The aim of our study was: (1) to explore, whether this QST protocol is feasible for children, (2) to detect distribution properties of QST data and the impact of body site, age and gender and (3) to establish reference values for QST in children and adolescents. The QST protocol of the DFNS with modification of instructions and pain rating was used in 176 children aged 6.12–16.12 years for six body sites. QST was feasible for children over 5 years of age. ANOVAs revealed developmental, gender and body site differences of somatosensory functions similar to adults. The face was more sensitive than the hand and/or foot. Younger children (6–8 years) were generally less sensitive to all thermal and mechanical detection stimuli but more sensitive to all pain stimuli than older (9–12 years) children, whereas there were little differences between older children and adolescents (13–17 years). Girls were more sensitive to thermal detection and pain stimuli, but not to mechanical detection and pain stimuli. Reference values differ from adults, but distribution properties (range, variance, and side differences) were similar and plausible for statistical factors. Our results demonstrate that the full QST protocol is feasible and valid for children over 5 years of age with their own reference values.

Dysfunction in Multiple Primary Afferent Fiber Subtypes Revealed By Quantitative Sensory Testing in Patients with Chronic Vincristine-Induced Pain

Vincristine is one of the frontline chemotherapy drugs for the treatment of numerous lymphoid neoplasias. The main dose-limiting complication of vincristine is the development of painful peripheral neuropathy. Although clinical reports have appeared in the literature detailing the symptoms of vincristine neuropathy, quantitative sensory testing data that might yield insight to dysfunction in subsets of primary afferents are lacking. In this report, pain descriptors and anatomical distributions of sensory abnormalities were collected in each patient. Touch detection threshold, sharpness detection threshold, the thresholds for the detection of skin warming, heat pain, skin cooling, and the perception of cooling-induced pain were measured in patients with chronic vincristine-induced pain in each area of sensory abnormality and in skin perceived as outside the affected areas. Elevated touch detection thresholds were observed both within and outside areas affected by pain and sensory abnormality. Elevated sharpness and warm detection thresholds were noted only in areas affected by pain. These data suggest that chronic vincristine-induced pain is associated with dysfunction in Aβ, Aδ, and C caliber primary afferent fibers. Deficits in Aβ fibers appear to precede and presage deficits in the other fiber types, whereas deficits in Aδ- and C-fiber function appear to be specifically associated with the generation of pain.