RESUMEN
BACKGROUND: Obesity is common among patients with multiple sclerosis (pwMS) and has been shown to exacerbate central inflammation, a key factor in disease progression. The purpose of this cross-sectional study is to examine the possible relationships between obesity, as measured by body mass index (BMI), and MS-related brain changes in atrophy and lesion volume, as measured from MRI, in a large, representative sample of pwMS. METHODS: BMI and MRI data, along with demographic and disease variables, were acquired from the Multiple Sclerosis Partners Advancing Technology and Health Solutions (MS PATHS) registry. Unadjusted and adjusted partial correlations, controlling for gender, race, age, education level, MS phenotype, disability and disease duration, examined the associations between BMI and MRI outcomes, which included brain parenchymal fraction, white matter fraction, gray matter fraction, thalamic volume, and T2 lesion volume. RESULTS: The sample consisted of 3,046 pwMS. Unadjusted and adjusted BMI-MRI correlations accounted for between 0.4% and 2.0% of shared variance (R2). When considering the relationship between MRI outcomes and BMI category (normal weight, overweight, obese), multiple regression analyses continued to show minimal association, with BMI category accounting for no more than 1.5% of shared variance. CONCLUSIONS: No clinically meaningful associations were found between BMI and MRI outcomes in this large, representative sample of MS patients, regardless of demographics and disease variables. These unexpected negative results will require replication with a longitudinal design using more precise measures of obesity.
Asunto(s)
Esclerosis Múltiple , Atrofia/patología , Encéfalo/diagnóstico por imagen , Encéfalo/patología , Estudios Transversales , Humanos , Imagen por Resonancia Magnética , Esclerosis Múltiple/complicaciones , Esclerosis Múltiple/diagnóstico por imagen , Esclerosis Múltiple/epidemiología , Obesidad/complicaciones , Obesidad/diagnóstico por imagen , Obesidad/epidemiologíaRESUMEN
OBJECTIVE: Performance validity tests (PVTs) are designed to detect nonvalid responding on neuropsychological testing, but their associations with disease-specific and other factors are not well understood in multiple sclerosis (MS). We examined PVT performance among MS patients and associations with clinical characteristics, cognition, mood, and disability status. METHOD: Retrospective data analysis was conducted on a sample of patients with definite MS (n = 102) who were seen for a clinical neuropsychological evaluation. Comparison samples included patients with intractable epilepsy seen for presurgical workup (n = 102) and patients with nonacute mild traumatic brain injury (mTBI; n = 50). Patients completed the Victoria Symptom Validity Test (VSVT) and validity cutoffs were defined as <16/24 and <18/24 on the hard items. RESULTS: In this MS cohort, 14.4% of patients scored <16 on the VSVT hard items and 21.2% scored <18. VSVT hard item scores were associated with disability status and depression, but not with neuropsychological scores, T2 lesion burden, atrophy, disease duration, or MS subtype. Patients applying for disability benefits were 6.75 times more likely to score <18 relative to those who were not seeking disability. Rates of nonvalid scores were similar to the mTBI group and greater than the epilepsy group. CONCLUSIONS: This study demonstrates that nonvalid VSVT scores are relatively common among MS patients seen for clinical neuropsychological evaluation. VSVT performance in this group relates primarily to disability status and psychological symptoms and does not reflect factors specific to MS (i.e., cognitive impairment, disease severity). Recommendations for future clinical and research practices are provided.