Decoding accuracy in supplementary motor cortex correlates with perceptual sensitivity to tactile roughness

Perceptual sensitivity to tactile roughness varies across individuals for the same degree of roughness. A number of neurophysiological studies have investigated the neural substrates of tactile roughness perception, but the neural processing underlying the strong individual differences in perceptual roughness sensitivity remains unknown. In this study, we explored the human brain activation patterns associated with the behavioral discriminability of surface texture roughness using functional magnetic resonance imaging (fMRI). First, a wholebrain searchlight multi-voxel pattern analysis (MVPA) was used to find brain regions from which we could decode roughness information. The searchlight MVPA revealed four brain regions showing significant decoding results: the supplementary motor area (SMA), contralateral postcentral gyrus (S1), and superior portion of the bilateral temporal pole (STP). Next, we evaluated the behavioral roughness discrimination sensitivity of each individual using the just-noticeable difference (JND) and correlated this with the decoding accuracy in each of the four regions. We found that only the SMA showed a significant correlation between neuronal decoding accuracy and JND across individuals; Participants with a smaller JND (i.e., better discrimination ability) exhibited higher decoding accuracy from their voxel response patterns in the SMA. Our findings suggest that multivariate voxel response patterns presented in the SMA represent individual perceptual sensitivity to tactile roughness and people with greater perceptual sensitivity to tactile roughness are likely to have more distinct neural representations of different roughness levels in their SMA. © 2015 Kim et al.close0

Effect of splint on pain, function and quality of life in trapeziometacarpal osteoarthritis patients?

Trapeziometacarpal (TM) Osteoarthritis is one of the most common osteoarthritis. It causes pain, loss of mobility and strength and affected function in daily life. Splint is one of the conservative treatments proposed to patients. The purpose of this study was to assess the effect of this conservative treatment on pain, function and quality of life at long-term. We sent 193 questionnaires to patients who received a CMC splint for their TM osteoarthritis. The CMC splint immobilizes only the TM joint and leaves free the interphalangeal joint of the thumb and the wrist. First, we comptuted how many patients had finally undergone surgical treatment. On the non-operated patients, we analyzed the pain (VAS), the function (QuickDASH score) and the quality of life (SF-12). We compared the results to literature and norms. Finally, 186 people could be included in the study ,115 we answered and 28 were operated on (24%). After 4 years (3.8±1.7 yrs) of conservative treatment, The VAS and QuickDASH scores were significantly worse comparatively to a cohort of healthy patients, trapezectomy and arthrodesis patients. The SF-12 scores were reduced from 20% comparative to norms. In conclusion, few patients had surgery after splinting as a conservative treatment. However, these non- operated patients do not provide good results

Effect of splint on pain, function and quality of life in trapeziometacarpal osteoarthritis patients?

Trapeziometacarpal (TM) Osteoarthritis is one of the most common osteoarthritis. It causes pain, loss of mobility and strength and affected function in daily life. Splint is one of the conservative treatments proposed to patients. The purpose of this study was to assess the effect of this conservative treatment on pain, function and quality of life at long-term. We sent 193 questionnaires to patients who received a CMC splint for their TM osteoarthritis. The CMC splint immobilizes only the TM joint and leaves free the interphalangeal joint of the thumb and the wrist. First, we comptuted how many patients had finally undergone surgical treatment. On the non-operated patients, we analyzed the pain (VAS), the function (QuickDASH score) and the quality of life (SF-12). We compared the results to literature and norms. Finally, 186 people could be included in the study ,115 we answered and 28 were operated on (24%). After 4 years (3.8±1.7 yrs) of conservative treatment, The VAS and QuickDASH scores were significantly worse comparatively to a cohort of healthy patients, trapezectomy and arthrodesis patients. The SF-12 scores were reduced from 20% comparative to norms. In conclusion, few patients had surgery after splinting as a conservative treatment. However, these non- operated patients do not provide good results.</jats:p

FRI0175 SEMI-DYNAMIC MRI OF THE EXTENSOR DIGITORUM TENDONS IN JACCOUD ARTHROPATHY

Background:Jaccoud arthropathy (JA) is a rare joint deformity mostly associated with systemic lupus erythematosus (SLE) (1). JA may be defined as a reversible deformity of the hands during flexion with ulnar deviation and swan neck deformities of the fingers. The physiopathology and the mechanisms leading to JA still remain to be elucidated.Objectives:To test the hypothesis that Jaccoud arthropathy (JA) in systemic lupus erythematosus (SLE) patients is associated with abnormal extensor digitorum (ED) tendons displacement during flexion of the metacarpophalangeal (MCP) joints.Methods:16 SLE patients with JA (JA+), 12 SLE patients without JA (JA-) and 24 control subjects were included in the study. Transverse spin echo T1-weighted MR sequences of the MCP joints in flexion and in extension were obtained in each hand of SLE patients and in one randomly-selected hand of control subjects. Two radiologists separately measured the amplitude and the direction of the displacement of the ED tendons with respect to the midline at the level of the MCP joints. Statistical analysis included two-way ANOVA with random effects to assess differences in amplitude (p&lt;0.0083), Fisher-Freeman-Halton exact test to assess differences in direction (p&lt;0.0063) and Gwet’s AC1 score to determine interobserver agreement.Results:Amplitude of the displacement of the ED tendons was statistically significantly higher in JA+ patients than in JA- patients and controls in flexion for both readers (p&lt;0.0001) and in extension for one reader (p&lt;0.0048). Ulnar deviation of the ED tendons was statistically significantly more frequent in JA+ patients than in JA- patients and controls in flexion and in extension for both readers (p&lt;0.0001). Interobserver agreement for the assessment of displacement was moderate to very good (0.51≤kappa≤0.93).Conclusion:JA is associated with abnormal displacement of the ED tendons in flexion and extension. Abnormal displacement of the ED tendons is absent in patients without JA.References:[1]Santiago MB. Miscellaneous non-inflammatory musculoskeletal conditions. Jaccoud’s arthropathy. Best Pract Res Clin Rheumatol. 2011;25(5):715-25.Figure 1.Axial spin echo T1-weighted images of a 49-year-old woman with SLE and JA (a) in flexion and (b) extension. In flexion, the extensor digitorum (ED) tendons of the 3rdand 4thfingers are completely displaced on the ulnar aspect of the metacarpal heads (white arrows) with no tendon visible on the dorsal aspect (arrowheads). In extension, the ED tendons of the 3rdand 4thfingers are slightly displaced on the ulnar side of the dorsal aspect of the metacarpal heads (black arrows).Figure 2.Axial spin echo T1-weighted images of the sex- and age-matched control subject of the patient from Figure 1 (a) in flexion and (b) extension. The extensor digitorum tendons of the 3rdand 4thfingers are normally positioned on the dorsal aspect of the metacarpal heads in flexion (white arrows) and extension (black arrows).Disclosure of Interests:Thomas Kirchgesner: None declared, Maria Stoenoiu: None declared, Nicolas Michoux: None declared, Xavier Libouton: None declared, Frederic Houssiau Grant/research support from: UCB, Consultant of: GSK, Bruno Vande Berg: None declared</jats:sec

Difficult to treat osteoarticulars infections : Focus on Mycobacterial and Fungal infection.

Bone and joint infections are rare but often devastating. While bacteria are most commonly encountered organisms, mycobacteria and fungi are less frequent. Management of the latter is often more complex, especially in the presence of foreign material. We will increasingly be faced with mycobacterial and fungal bone infections, as medical conditions and newer therapeutics lead to more immunosuppression. In this article, we will review osteomyelitis, septic arthritis and peri-prosthetic joint infections related to mycobacteria and fungi