Objective: Quantitative Sensory Testing (QST) is a neurosensory testing method that delivers precise,standardized stimuli to body surfaces and obtains quantifiable responses from the test subject. Recent trigeminal QST studies have demonstrated that most intraoral QST parameters are sufficiently reliable. This ongoing pilot study aimed to compare the reliability of multi-divisional trigeminal extraoral and intraoral QST.
Method: The modified German QST protocol of 13 tests (Pigg et al. PAIN, 2010) was used to measure all three divisions of the trigeminal nerve bilaterally in patients with Atypical Odontalgia (AO), a chronic pain condition, in cases and age- and sex-matched controls. QST employed controlled thermal, tactile and painful stimuli applied to the gingiva (intraoral), face (extraoral) and hand (control site). Since all QST parameters in the protocol are the average of 3 to 5 individual tests (e.g. cold detection threshold value is the average of three successive trials), the Coefficient of variation (CV) could be calculated for each parameter to evaluate test-retest reliability, and be used to potentially compare between protocols, cases, controls and anatomic sites. All CV values were multiplied by 100.
Result: QST was conducted on the hand, 6 extraoral and 4 intraoral sites in all three trigeminal divisions in the first 11 controls (6 Female, aged 42-62), (5 Male, aged 21-73) and first 4 AO cases (1 Male aged 73, 3 Females, aged 39 - 59). Lower values of CV denoted higher reliability. Control values for 5 of 13 QST parameters are listed in the table; case reliability will be reported when enrollment is over 10 subjects.
Table of Controls
| Coefficient of Variation of each QST parameter comparing Extraoral vs. Intraoral |
|
| Site |
|
V2 |
V2 |
V3 |
V3 |
ALL |
ALL |
| Parameter |
Hand |
Extraoral |
Intraoral |
Extraoral |
Intraoral |
Extraoral |
Intraoral |
| Pressure Pain Threshold (PPT) |
19 |
11 |
27 |
14 |
22 |
12 |
24 |
| Vibration Detection Threshold (VDT) |
7 |
10 |
4 |
7 |
3 |
8 |
3 |
| Cold Detection Threshold (CDT) |
19 |
26 |
22 |
28 |
24 |
28 |
23 |
| Warm Detection Threshold (WDT) |
18 |
15 |
17 |
20 |
18 |
17 |
17 |
| Mechanical Detection Threshold (MDT) |
49 |
76 |
44 |
50 |
57 |
63 |
51 |
Conclusion: Reliability as measured by CV differed between QST techniques, QST parameters and by anatomic site. Intraoral sites showed higher reliability for VDT, while extraoral was better for PPT, and both approaches similar for CDT, WDT and MDT.
