Qualitative Sensory Testing Research Articles

Centella Asiatica Triterpene Extract Is Effective in Treating Diabetic Neuropathy - A Pilot Study (P03.192)

Objective: To examine if CA triterpenes are effective in treating length-dependent neuropathy in DM patients. Background Many DM patients suffer from neuropathy which may be mediated by microangiopathy. Centella asiatica (CA) is an Indian herb widely used as a nerve tonic, and to treat vascular insufficiency. Its triterpene components are well characterized. We have shown that CA extract promotes neurite growth in vitro and the recovery of sciatic nerve injury in vivo. Design/Methods: Thirty-three subjects completed this 52-week randomized, double-blind, placebo-controlled study. Indena, Inc. supplied the study drug (Centella asiatica Selected Triterpenes, CAST). The first 12 weeks were a dose-escalating phase and the subjects remained on a stable dose of 240mg/day for 40 weeks. The primary outcome measure was Total Symptom Score (TSS) measuring the severity of parasthesia, numbness, pain and burning sensation. Secondary outcome measures were nerve conduction studies, Neurological Disability Score (NDS), and Qualitative Sensory Testing (QST). Results: At baseline, there was no difference in any outcome measures between treatment (n=15, 3F/12M) and placebo (n=18, 6F/12M) groups (TSS: 8.4±2.9 vs 8.3±2.5; combined sensory nerve action potential amplitude of sural and radial, SNAP: 18.8±8.9 vs 17.7±15.4 μV). With treatment, subjects in the treatment group had significantly lower TSS scores (6.3±0.5 vs 7.4±0.5 at week 29, 6.4±0.4 vs 7.5±0.4 at week 52, p Conclusions: CAST, at a dose of 240 mg QD, is safe and well tolerated. CAST is effective in reducing the sensory symptoms subjectively and preventing the reduction of the sensory nerve action potential amplitude objectively. A larger study is needed to confirm these findings. Supported by: National Center for Complementary and Alternative Medicine. Disclosure: Dr. Lou has nothing to disclose. Dr. Dimitrova has nothing to disclose. Dr. Soumyanath has received personal compensation for activities with Oregon9s Wild Harvest as a consultant. Dr. Soumyanath has received license fee and royalty payments from AdPharma Inc. Dr. Soumyanath has received research support from AdPharma Inc., and Mediherb Integra. Dr. Belding has nothing to disclose. Dr. Le has nothing to disclose. Dr. Seifer has nothing to disclose. Dr. Arnold has nothing to disclose.

Sickle cell disease and pain: potential dysfunction in A delta fiber transmission

Although sickle cell disease is generally characterized by varying degrees and patterns of clinical manifestations, its major features usually include severe episodes of pain. As part of a comprehensive pain assessment protocol on mechanisms of sickle cell pain, we are investigating how pain and inflammatory processes may be triggered in part by the disruption of normal NO pathways. Qualitative sensory testing (QST) procedures were conducted on subjects seen at the National Institutes of Health (NIH) Clinical Center, Bethesda, Md. Average age of subjects is 44.6 years (range: 31 to 52); 60% female; 30% male; 100% of the subjects reported experiencing chronic daily or almost daily pain. QST was used to assess experimental sensory and pain threshold levels, quantify presence of hyperalgesia, and compare pain threshold, detection threshold, and the degree of temporal summation of any second pain in response to thermal stimulation. All subjects reported heat thresholds within normal limits (48.7oC + or - 1.73 oC); while none of the sickle cell subjects reported cold thresholds within normal limits (2.3oC + or - 2.0o C). One subject did not report any perception of cold pain and the procedure was stopped to avoid tissue damage. This novel observation may have implications for understanding pain perception in people with sickle cell disease.

Quantitative assessment of sensory functions after 3 surgical approaches for trigeminal neuralgia by current perception threshold measurement

Objective To quantitatively identify and grade trigeminal sensory functions after 3 major surgical procedures of trigeminal neuralgia using a newly developed quantitative sensory testing technique, current perception threshold measurement (CPTM). Methods In the current study, there were 48 trigeminal neuralgia patients without history of prior surgical treatment. These patients received one of the following 3 surgical procedures, microvascular decompression (MVD), peripheral nerve block with alcohol (PNB), or percutaneous radiofrequency thermocoagulation (PRFT). The quantitative sensory testing measurement, CPTM, and conventional qualitative sensory testing measurements were performed preoperatively and postoperatively to evaluate and grade the trigeminal sensory functions. All 3 major cutaneous sensory fiber types, large myelinated fibers (A beta), small myelinated fibers (A delta) and unmyelinated fibers(C) were allowed to quantitatively evaluate and grade by CPTM. The results of the measurements were statistically analyzed using a one-way analysis of variance (single factor). Each subject was his/her own control for comparison of the preoperative to postoperative state on the asymptomatic and symptomatic sides. Subjects were tested 48 h preoperatively and 4 weeks postoperatively. Results PNB with alcohol and PRFT caused significant sensory dysfunction postoperatively in every fiber type, indicating damage to all fibers. On the contrary, the sensory function in all 3 fiber types was unchanged after MVD management. Conclusion Among the 3 major surgical procedures tested, only MVD preserves sensory function in trigeminal system. CPTM is of quantitative nature on the evaluation of sensory functions of nerve fibers

Nerve Puncture and Apparent Intraneural Injection during Ultrasound-guided Axillary Block Does Not Invariably Result in Neurologic Injury

Nerve puncture by the block needle and intraneural injection of local anesthetic are thought to be major risk factors leading to neurologic injury after peripheral nerve blocks. In this study, the author sought to determine the needle-nerve relation and location of the injectate during ultrasound-guided axillary plexus block. Using ultrasound-guided axillary plexus block (10-MHz linear transducer, SonoSite, Bothel, WA; 22-gauge B-bevel needle, Becton Dickinson, Franklin Parks, NJ), the incidence of apparent nerve puncture and intraneural injection of local anesthetic was prospectively studied in 26 patients. To determine the onset, success rate, and any residual neurologic deficit, qualitative sensory and quantitative motor testing were performed before and 5 and 20 min after block placement. At a follow-up 6 months after the blocks, the patients were examined for any neurologic deficit. Twenty-two of 26 patients had nerve puncture of at least one nerve, and 21 of 26 patients had intraneural injection of at least one nerve. In the entire cohort, 72 of a total of 104 nerves had intraneural injection. Sensory and motor testing before and 6 months after the nerve injections were unchanged. Under the conditions of this study, puncturing of the peripheral nerves and apparent intraneural injection during axillary plexus block did not lead to a neurologic injury.

Lower extremity sensory function in children with cerebral palsy

(1) To determine the feasibility of qualitative sensory testing in the lower extremities (LE) of children with cerebral palsy (CP), especially spastic diplegia. (2) To determine if there is a detectable difference in qualitative LE sensory function in children with CP compared to typical children. (3) To determine if dorsal rhizotomy results in detectable changes in LE sensory function in children with spastic diplegia. Objectives 1 and 2: Prospective observational cohort study. Objective 3: Add-on to prospective interventional studies. Regional tertiary children's hospital. Objectives 1 and 2: 62 children with CP and 65 typical children between 3-18 years of age. Objective 3: 34 children with spastic diplegia. Objectives 1 and 2: None. Objective 3: Dorsal rhizotomy. Pain, light touch, direction of scratch, vibration, toe position and knee position using standard qualitative techniques. Objective 1: 32 (52%) children with CP and 55 (85%) typical children completed all items (p = 0.09). Objective 2: Summary scores for separate LE sensory modalities were lower in children with CP for direction of scratch (p < 0.001), toe position (p = 0.01) and vibration sense (p = 0.01). Objective 3: No changes of LE sensory function. LE sensory testing in young children with CP is feasible. There is a qualitative sensory deficit in this sample of children with CP and specifically in children with spastic diplegia that is traditionally associated with dorsal column sensory modalities. A conservative dorsal rhizotomy does not produce a measurable change in LE sensory function in this sample of children with spastic diplegia.