A comparison of three clustering methods for finding subgroups in MRI, SMS or clinical data: SPSS TwoStep Cluster analysis, Latent Gold and SNOB

Background: There are various methodological approaches to identifying clinically important subgroups and one method is to identify clusters of characteristics that differentiate people in cross-sectional and/or longitudinal data using Cluster Analysis (CA) or Latent Class Analysis (LCA). There is a scarcity of head-to-head comparisons that can inform the choice of which clustering method might be suitable for particular clinical datasets and research questions. Therefore, the aim of this study was to perform a head-to-head comparison of three commonly available methods (SPSS TwoStep CA, Latent Gold LCA and SNOB LCA). Methods. The performance of these three methods was compared: (i) quantitatively using the number of subgroups detected, the classification probability of individuals into subgroups, the reproducibility of results, and (ii) qualitatively using subjective judgments about each program's ease of use and interpretability of the presentation of results.We analysed five real datasets of varying complexity in a secondary analysis of data from other research projects. Three datasets contained only MRI findings (n = 2,060 to 20,810 vertebral disc levels), one dataset contained only pain intensity data collected for 52 weeks by text (SMS) messaging (n = 1,121 people), and the last dataset contained a range of clinical variables measured in low back pain patients (n = 543 people). Four artificial datasets (n = 1,000 each) containing subgroups of varying complexity were also analysed testing the ability of these clustering methods to detect subgroups and correctly classify individuals when subgroup membership was known. Results: The results from the real clinical datasets indicated that the number of subgroups detected varied, the certainty of classifying individuals into those subgroups varied, the findings had perfect reproducibility, some programs were easier to use and the interpretability of the presentation of their findings also varied. The results from the artificial datasets indicated that all three clustering methods showed a near-perfect ability to detect known subgroups and correctly classify individuals into those subgroups. Conclusions: Our subjective judgement was that Latent Gold offered the best balance of sensitivity to subgroups, ease of use and presentation of results with these datasets but we recognise that different clustering methods may suit other types of data and clinical research questions

The association between subgroups of MRI findings identified with latent class analysis and low back pain in 40-year old Danes

Background: Research into the clinical importance of spinal MRI findings in patients with low back pain (LBP) has primarily focused on single imaging findings, such as Modic changes or disc degeneration, and found only weak associations with the presence of pain. However, numerous MRI findings almost always co-exist in the lumbar spine and are often present at more than one lumbar level. It is possible that multiple MRI findings are more strongly associated with LBP than single MRI findings. Latent Class Analysis is a statistical method that has recently been tested and found useful for identifying latent classes (subgroups) of MRI findings within multivariable datasets. The purpose of this study was to investigate the association between subgroups of MRI findings and the presence of LBP in people from the general population. Methods: To identify subgroups of lumbar MRI findings with potential clinical relevance, Latent Class Analysis was initially performed on a clinical dataset of 631 patients seeking care for LBP. Subsequently, 412 participants in a general population cohort (the ‘Backs on Funen’ project) were statistically allocated to those existing subgroups by Latent Class Analysis, matching their MRI findings at a segmental level. The subgroups containing MRI findings from the general population were then organised into hypothetical pathways of degeneration and the association between subgroups in the pathways and the presence of LBP was tested using exact logistic regression. Results: Six subgroups were identified in the clinical dataset and the data from the general population cohort fitted the subgroups well, with a median posterior probability of 93%–100%. These six subgroups described two pathways of increasing degeneration on upper (L1-L3) and lower (L4-L5) lumbar levels. An association with LBP was found for the subgroups describing severe and multiple degenerative MRI findings at the lower lumbar levels but none of the other subgroups were associated with LBP

Genetic susceptibility of intervertebral disc degeneration among young Finnish adults

<p>Abstract</p> <p>Background</p> <p>Disc degeneration (DD) is a common condition that progresses with aging. Although the events leading to DD are not well understood, a significant genetic influence has been found. This study was undertaken to assess the association between relevant candidate gene polymorphisms and moderate DD in a well-defined and characterized cohort of young adults. Focusing on young age can be valuable in determining genetic predisposition to DD.</p> <p>Methods</p> <p>We investigated the associations of existing candidate genes for DD among 538 young adults with a mean age of 19 belonging to the 1986 Northern Finland Birth Cohort. Nineteen single nucleotide polymorphisms (SNP) in 16 genes were genotyped. We evaluated lumbar DD using the modified Pfirrmann classification and a 1.5-T magnetic resonance scanner for imaging.</p> <p>Results</p> <p>Of the 538 individuals studied, 46% had no degeneration, while 54% had DD and 51% of these had moderate DD. The risk of DD was significantly higher in subjects with an allele G of <it>IL6 </it>SNPs rs1800795 (OR 1.45, 95% CI 1.07-1.96) and rs1800797 (OR 1.37, 95% CI 1.02-1.85) in the additive inheritance model. The role of <it>IL6 </it>was further supported by the haplotype analysis, which resulted in an association between the GGG haplotype (SNPs rs1800797, rs1800796 and rs1800795) and DD with an OR of 1.51 (95% CI 1.11-2.04). In addition, we observed an association between DD and two other polymorphisms, <it>SKT </it>rs16924573 (OR 0.27 95% CI 0.07-0.96) and <it>CILP </it>rs2073711 in women (OR 2.04, 95% CI 1.07-3.89).</p> <p>Conclusion</p> <p>Our results indicate that <it>IL6</it>, <it>SKT </it>and <it>CILP </it>are involved in the etiology of DD among young adults.</p

DIA1R Is an X-Linked Gene Related to Deleted In Autism-1

Background: Autism spectrum disorders (ASDs) are frequently occurring disorders diagnosed by deficits in three core functional areas: social skills, communication, and behaviours and/or interests. Mental retardation frequently accompanies the most severe forms of ASDs, while overall ASDs are more commonly diagnosed in males. Most ASDs have a genetic origin and one gene recently implicated in the etiology of autism is the Deleted-In-Autism-1 (DIA1) gene. Methodology/Principal Findings: Using a bioinformatics-based approach, we have identified a human gene closely related to DIA1, we term DIA1R (DIA1-Related). While DIA1 is autosomal (chromosome 3, position 3q24), DIA1R localizes to the X chromosome at position Xp11.3 and is known to escape X-inactivation. The gene products are of similar size, with DIA1 encoding 430, and DIA1R 433, residues. At the amino acid level, DIA1 and DIA1R are 62 % similar overall (28 % identical), and both encode signal peptides for targeting to the secretory pathway. Both genes are ubiquitously expressed, including in fetal and adult brain tissue. Conclusions/Significance: Examination of published literature revealed point mutations in DIA1R are associated with X-linked mental retardation (XLMR) and DIA1R deletion is associated with syndromes with ASD-like traits and/or XLMR. Together, these results support a model where the DIA1 and DIA1R gene products regulate molecular traffic through the cellular secretory pathway or affect the function of secreted factors, and functional deficits cause disorders with ASD-lik

Presence and Flow in Virtual Environments: an Explorative Study

Virtual environments (VEs) are thought to elicit a sense of presence to the user. The sense of presence is considered as a psychological experience of being in a world generated by the computer instead of using the computer from the outside. As a field of research the psychology of VE is quite new and not well explored. In this study the three components of the sense of presence are examined: spatial awareness, attention and the realness of the VE. The three components solution of presence is accused of following Cartesian tradition in separating perception from action. Interaction is considered an important part of the experience of presence. Some authors consider it as the only determinant of presence. The purpose of this study was to explore empirically this human experience. The idea was to integrate the presented presence components into a cognitive-emotional appraisal process from the environment. This type of an appraisal process in generating emotions dominates the field of modern psychological emotion theories. It has also been presented that similar appraisal process precedes optimal experience, i.e., flow. Flow has been used as a metrics to evaluate human computer interaction. However, there are only few studies in which both presence and flow has been measured. In this study the participants gained experiences while conducting a simple search task in a virtual CAVEtm. These experiences were measured with a questionnaire. Based on the results a three-dimensional framework was constructed. This framework integrated the experience of presence and interaction as well as an appraisal process from the environment based on oneis skills and challenges provided by the environment. In the appraisal process also personal relevance and evaluation of the interactivity of the VE are included. Framework also included two basic emotional dimensions arousal and control, which are considered important in producing the overall emotional experience. The framework was used to explain different endpoint experiences gained by the users. The results showed that the sense of presence is an integral part of the flow experience in VEs and in order to experience VE positively a user should experience both presence and flow in VE. Although, the framework needs more careful studying, it provides a fair depiction of the basic dynamics behind a subjective experience in VE. 

Degenerative findings on MRI of the lumbar spine:prevalence, environmental determinants and association with low back symptoms

Abstract Earlier studies on lumbar degenerative imaging findings in magnetic resonance imaging (MRI) have been done mainly in adult populations and the associations of degenerative findings with low back pain (LBP) are controversial. Only a few studies have involved adolescents and young adults. Heritability has been acknowledged as the only explicit risk factor of disc degeneration (DD). This study investigated the prevalence and environmental determinant of lumbar degenerative findings in MRI and their association with low back symptoms among young adults. The data were based on two physical assessments, three questionnaires and one lumbar MRI that were executed on members of the Oulu Back Study (n=558), a subsample of Northern Finland Birth Cohort 1986, between 16 and 21 years of age. Prevalences of lumbar DD (54%), bulging (25%), protrusion (18%) and Schmorl’s node (17%) were high, whereas other degenerative findings were rare among young adults. Males had higher prevalence of DD and Schmorl’s nodes than females. DD and herniations were associated with low back symptoms. On the other hand, symptoms were present among subjects without DD or other abnormal findings on MRI. Of the environmental determinants, high body mass index and MRI-based obesity measurements of visceral adiposity were associated with lumbar DD among males. Waist circumference and smoking showed a comparable association with DD among males, but the level of physical activity was not associated with DD in either gender. Low back symptoms are more common among young adults with a higher degree of DD or presence of disc herniation. Smoking and overweight are associated with lumbar DD among young male adults.Tiivistelmä Aikaisempia tutkimuksia magneettikuvantamisella (MK) todetuista lannerangan rappeumamuutoksista ja niiden yhteyksistä alaselkäkipuun on tehty lähinnä aikuisväestöllä ja tulokset ovat ristiriitaisia. Vain muutamia tutkimuksia on tehty alle 25-vuotiailla. Välilevyrappeuman mahdollisista riskitekijöistä vain perimästä on vahvaa näyttöä. Tässä tutkimuksessa tarkasteltiin MK:lla todettujen lannerangan rappeumamuutosten esiintyvyyttä, niihin vaikuttavia ympäristötekijöitä ja yhteyttä alaselkäoireisiin nuorilla aikuisilla. Tutkimuksen aineisto perustui kahteen kliiniseen tutkimukseen, kolmeen kyselyyn ja yhteen MK:een, jotka toteutettiin Pohjois-Suomen syntymäkohortti 1986:een kuuluville Oulun selkätutkimuksen koehenkilöille (n=558) 16-21 vuoden iässä. Lannerangan välilevyrappeumalla (54 %), välilevyn pullotuksilla (bulge; 25 %), sellaisilla välilevyn pullistumilla jotka eivät läpäisseet selkärangan takimmaista pitkittäissidettä (protruusio; 18 %) sekä päätelevyn läpi suuntautuvilla välilevyn pullistumilla (Schmorlin keräset; 17 %) oli korkea esiintyvyys nuorilla aikuisilla, kun taas muut kuvantamislöydökset olivat harvinaisia. Välilevyrappeuma ja Schmorlin keräset olivat yleisempiä miehillä. Sekä välilevyrappeuma että pullistumat olivat yhteydessä alaselkäoireisiin molemmilla sukupuolilla, mutta kaikilla oireisilla ei todettu poikkeavia löydöksiä MK:ssa. Ympäristötekijöistä korkea kehon painoindeksi ja MK:sta mitatut rasvan määrää mittaavat muuttujat olivat miehillä yhteydessä välilevyrappeumaan. Miehillä vyötärönympärys ja tupakointi olivat heikommin yhteydessä välilevyrappeumaan, kun taas liikunta-aktiivisuus ei ollut kummallakaan sukupuolella yhteydessä rappeumaan. Alaselkäoireet ovat yleisempiä nuorilla aikuisilla, joilla on vaikea-asteisempi välilevyrappeuma tai välilevyn pullistuma. Tupakointi ja ylipaino ovat yhteydessä lannerangan välilevyrappeumaan nuorilla aikuisilla miehillä

Bursiitit:diagnostiikka ja hoito

Tiivistelmä Syvät limapussit ovat synnynnäisiä rakenteita, kun taas pinnalliset bursat kehittyvät kuormituksen ­seurauksena. Pinnallisten infektiivisten bursiittien hoitona on ripeä antibioottihoidon aloitus limapussin punktion ja ­bakteeriviljelyn jälkeen. Pinnallisten inflammatoristen bursiittien hoitona on punktio ja lepo. Kuormitusperäisiin syviin bursiitteihin käytetyt kortikosteroidi-injektiot voivat lievittää oireita, ­mutta niistä ei ole pitkävaikutteista hyötyä. Syvissä bursiiteissa tulee huomioida usein taustalla vaikuttava lisääntynyt tai poikkeava epäsuora ­mekaaninen kuormitus, tarvittaessa kuntoutuksen avulla.English summary Diagnosis and treatment of bursitis A bursa is a structure that reduces friction between soft tissues and bony structures. Bursitis can be either aseptic or septic. Aseptic bursitis is more frequent. Septic bursitis occurs mainly in superficial bursae. Infection in deep bursae is less frequent. The diagnosis of superficial bursitis is fairly straightforward based on clinical examination, but imaging can be useful in some cases. Treatment consists of aspiration of the bursa and relative rest. The diagnosis of deep bursitis is more challenging and ultrasound or magnetic resonance imaging can be helpful in reaching the diagnosis. Indirect mechanical loading is a common contributing factor in deep bursitis, and tendinopathy findings are frequent in adjacent tendons. The treatment in the acute phase consists of relative rest and medication. However, when aiming for long-term effects, improvement in the loading tolerance of the bursa and the loading capacity of the adjacent tendons should be targeted in rehabilitation. Corticosteroid injections can be useful in the short-term, but they do not have any long-term benefit and, thus, the use of injections should be considered carefully. Surgery is required infrequently