1. 4RehaClinic, Bad Zurzach/Baden, 5University of Zurich
Quantitative sensory testing in chronic pain patients with nondermatomal sensory deficits
1Riederer F*, 2Landmann G*, 1Gantenbein AR, 2Stockinger L, 3Egloff N, 4,5Sándor PS, 2Schleinzer W
1Department of Neurology, University Hospital Zurich, 2Centre for Pain Medicine, Swiss Paraplegic Centre, Nottwil
3Psychosomatic Division, C.L. Lory-Haus, Department of General Internal Medicine, Inselspital, University Hospital Bern
4RehaClinic, Bad Zurzach/Baden, 5University of Zurich
*Equal contribution
UniversitätsSpital Zürich
Introduction
About 20-40% of chronic pain patients have widespread sensory deficits often in hemisensory distribution ipsilateral to the site of pain1, a phenomenon termed nondermatomal sensory deficits (NDSDs; Fig. 1). Patients with NDSDs show no pathological findings in standard investigations, but decreased activity in the contralateral thalamus and somatosensory cortex have been found in PET and fMRI studies2-3. Decreased sensitivity to light touch, temperature or pinprick has been described. Quantitative sensory testing (QST) revealed increased detection thresholds for touch, cold and heat, as well as an increased heat pain threshold in patients with complex regional pain syndrome and hemisensory deficit4. It was the aim of the present study to compare QST profiles in chronic pain patients with and without hemisensory NDSDs
Table 2: Demographic data
Pain +
NDSDs
n=25
Pain -NDSDs
n=11 p
(Chi-square / T-test
Age in y (mean±SD)
Sex female (n)
42±10.0
n=17
47±9.1
n=6
0.147
0.475
Number of pain sites 1 2 ≥3 6 18 8
0.524
Pain duration y (mean±SD)
7.2 ±6.5
8.8±5.8
0.495
Intensity (von Korff)
74.3 ±14.3
72.6 ±15.0
0.762
Complete NDSD
Incomplete NDSD 19
n.a
Table 3: Results of questionnaires
Pain + NDSDs
n=25
Pain - NDSDs
n=11 p
(Chi-square / T-test
HADS-anxiety*
HADS-depression*
11.8±5.0
10.2±5.3
7.1±3.4
7.9±5.3
0.007
0.235
SF (95% CI§)
physical ( ) mental ( )
29±6.3
37±9.8
37±8.8
42±9.8
0.008
0.111
CPGQ (von Korff)
Grade 2 (n):
Grade 3 (n):
Grade 4 (n): 2 6 16 5 1
0.058
MPSS
Stage I (n):
Stage II (n):
Stage III(n): 4 20 3
0.053
*Normal ≤ 7
§ General population
Results
All patients had high ratings for pain severity (CPGQ) and chronicity (MPSS) and low ratings for health related quality of life (SF12). Anxiety (HADS-A) scores were significantly higher and physical health related quality of life (SF12) scores significanly lower in patients with NDSDs.
Patients with NDSDs had a significantly lower sensitivity on the side ipsilateral to the pain for several parameters, with MDT, MPT, and CDT lower in two or more regions. Side differences were least pronounced on the dorsum of the hand, where only the parameter MDT was significantly lower on the ipsilateral side. In patients without NDSDs no significant side differences were found for any of the parameters.
Case 2
Case 1
Pain
NDSDs
Fig. 1: Body maps of two patients with leftsided chronic pain disorder and NDSDs.
Methods
In the ongoing study 25 chronic pain patients with hemisensory NDSDs, and 11 without NDSDs, in whom lesions of the central or peripheral nervous system had been excluded, were enrolled. Patients were investigated independently by two experienced neurologists at different dates. Only patients with consistent sensory deficits on one side of the body (group pain + NDSDs) or who consistently showed no sensory abnormality in the clinical investigation (group pain - NDSDs) were included. Patients with other neurological deficits, severe psychiatric disorders including more than mild to moderate mood disorders, abnormalities in cerebral MRI or nerve conduction studies were excluded. Pain severity was assessed with the Chronic Pain Grading Questionnaire (CPGQ), pain chronicity with the MPSS, psychological distress with Hospital Anxiety and Depression Scale (HADS), and health-related quality of life using the SF-12.
The following QST parameters were investigated in the face (cheek), dorsum of hand, and dorsum of foot: Cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical detection threshold (MDT), mechanical pain threshold (MPT), vibration detection threshold, pressure pain threshold (PPT).
Fig.3: Averaged QST-profiles in chronic pain patients with (left column) and without NDSDs (right column). The upper panel corresponds to the face, the middle to the hand and the lower to foot. Z-scores ±SD are shown for all parameters. Significant side differnces were only observed in patients with NDSDs. *p<0.05, **p<0.01 A B C
Conclusions
QST confirmed the clinical finding that in patients with NDSDs the threshold to different sensory modalities is significantly increased on the side of pain compared to the contralateral side. This is in accordance with a QST study in complex regional pain syndrome with sensory deficits.
The involvement of different sensory modalities would be consistent with a central mechanism for hemisensory impairment. Patients with NDSDs show high psychological distress and low disease related quality of life.
Fig. 2: Quantitative sensory testing (examples) : CDT, WDT, CPT, HPT are determined using termode (A), MPT with weighted pinprick stimulators (B), PPT with a pressure algometer (C).
Table 1: Main pain diagnoses
Pain + NDSDs
n=25
Pain - NDSDs
n=11
Headache 5 0 
Neck pain unspecific 6 7
Shoulder pain 2
Abdominal pain 1
Low back pain unspecific 3
Pelvic pain
Leg pain
Fibromyalgia
References
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Der Wissenschaftsfonds.