Monday, March 19, 2012

CRPS Research: QST Profiling and Central Motor Processing

For weeks there is nothing in the research news about CRPS, then, bam!  Today I received notice of the following two items, as well as a bit of a education being given by the RSDSA Scientific Board in an exchange of letters over a proposed redefinition of neuropathic pain. [For that discussion, check out the Letters to the Editor in PAIN.]

QST = Quantitative Sensory Testing

Sensory signs in complex regional pain syndrome and peripheral nerve injury
PAIN Volume 153, Issue 4, Pages 765-774 , April 2012

Janne Gierthmühlen, Christoph Maier, Ralf Baron, Thomas Tölle, Rolf-Detlef Treede, Niels Birbaumer, Volker Huge, Jana Koroschetz, Elena K. Krumova, Meike Lauchart, Christian Maihöfner, Helmut Richter, Andrea Westermann, the German Research Network on Neuropathic Pain (DFNS) study group

Janne Gierthmuhlen is the corresponding author. Address: Division of Neurological Pain Research and Therapy, Department of Neurology, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Arnold-Heller-Strasse 3, Haus 41, Kiel 24105, Germany. Tel.: +49 431 597 8510; fax: +49 431 597 8530.

Received 7 March 2011; received in revised form 1 October 2011; accepted 7 November 2011. published online 12 December 2011.

QST revealed more similarities than differences between CRPS-I, CRPS-II, and PNI: sensory loss occurred in 63% of CRPS-I and sensory gain in 81% of PNI patients.

This study determined patterns of sensory signs in complex regional pain syndrome (CRPS) type I and II and peripheral nerve injury (PNI). Patients with upper-limb CRPS-I (n=298), CRPS-II (n=46), and PNI (n=72) were examined with quantitative sensory testing according to the protocol of the German Research Network on Neuropathic Pain. The majority of patients (66%–69%) exhibited a combination of sensory loss and gain. Patients with CRPS-I had more sensory gain (heat and pressure pain) and less sensory loss than patients with PNI (thermal and mechanical detection, hypoalgesia to heat or pinprick). CRPS-II patients shared features of CRPS-I and PNI. CRPS-I and CRPS-II had almost identical somatosensory profiles, with the exception of a stronger loss of mechanical detection in CRPS-II. In CRPS-I and -II, cold hyperalgesia/allodynia (28%–31%) and dynamic mechanical allodynia (24%–28%) were less frequent than heat or pressure hyperalgesia (36%–44%, 67%–73%), and mechanical hypoesthesia (31%–55%) was more frequent than thermal hypoesthesia (30%–44%). About 82% of PNI patients had at least one type of sensory gain. QST demonstrates more sensory loss in CRPS-I than hitherto considered, suggesting either minimal nerve injury or central inhibition. Sensory profiles suggest that CRPS-I and CRPS-II may represent one disease continuum. However, in contrast to recent suggestions, small fiber deficits were less frequent than large fiber deficits. Sensory gain is highly prevalent in PNI, indicating a better similarity of animal models to human patients than previously thought. These sensory profiles should help prioritize approaches for translation between animal and human research.

Keywords: Complex regional pain syndrome, CRPS, Peripheral nerve injury, Quantitative sensory testing, Somatosensory, Pain



Kinematic parameters of running stride

Motor control in complex regional pain syndrome: A kinematic analysis
PAIN Volume 153, Issue 4, Pages 805-812, April 2012

J.C.M. Schilder, A.C. Schouten, R.S.G.M. Perez, F.J.P.M. Huygen, A. Dahan, L.P.J.J. Noldus, J.J. van Hilten, J. Marinus

Schilder is the corresponding author. Address: Department of Neurology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands. Tel.: +31 71 5262895; fax: +31 71 5248253.

Received 16 August 2011; received in revised form 9 November 2011; accepted 23 December 2011. published online 15 February 2012.

TOC Summary
CRPS patients perform repetitive finger movements slower and with more hesitations with both the affected hand and the unaffected hand, pointing at impaired central motor processing.

This study evaluated movement velocity, frequency, and amplitude, as well as the number of arrests in three different subject groups, by kinematic analysis of repetitive movements during a finger tapping (FT) task. The most affected hands of 80 patients with complex regional pain syndrome (CRPS) were compared with the most affected hands of 60 patients with Parkinson disease (PD) as well as the nondominant hands of 75 healthy control (HC) subjects. Fifteen seconds of FT with thumb and index finger were recorded by a 60-Hz camera, which allowed the whole movement cycle to be evaluated and the above mentioned movement parameters to be calculated. We found that CRPS patients were slower and tapped with more arrests than the two other groups. Moreover, in comparison with the hands of the HC subjects, the unaffected hands of the CRPS patients were also impaired in these domains. Impairment was not related to pain. Dystonic CRPS patients performed less well than CRPS patients without dystonia. In conclusion, this study shows that voluntary motor control in CRPS patients is impaired at both the affected as well as the unaffected side, pointing at involvement of central motor processing circuits.

Keywords: Bradykinesia, Central motor processing, CRPS, Kinematic analysis, Motor control


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