Cognitive impairment and its relation to imaging measures in multiple sclerosis: a study using a computerized battery.

BACKGROUND AND PURPOSE: Cognitive impairment (CI) is an important component of multiple sclerosis (MS) disability. A complex biological interplay between white matter (WM) and gray matter (GM) disease likely sustains CI. This study aims to address this issue by exploring the association between the extent of normal WM and GM disease and CI. METHODS: Cognitive function of 24 MS patients and 24 healthy volunteers (HVs) was studied using the Automated Neuropsychological Assessment Metrics (ANAM) battery. WM focal lesions and normal appearing WM (NAWM) volume in patients, cortical thickness (CTh) and deep GM structure volumes in both patients and HVs were measured by high field strength (3.0-Tesla; 3T) imaging. RESULTS: An analysis of covariance showed that patients performed worse than HVs on Code Substitution Delayed Memory (P = .04) and Procedural Reaction Time (P = .05) indicative of reduced performance in memory, cognitive flexibility, and processing speed. A summary score (Index of Cognitive Efficiency) indicating global test battery performance was also lower for the patient group (P = .04). Significant associations, as determined by the Spearman rank correlation tests, were noted between each of these 3 cognitive scores and measures of NAWM volume [CDD-TP1(r = .609; P = .0035), PRO-TP1 (r = .456; P = .029) and ICE (r = .489; P = .0129)], CTh (r = .5; P ≤ .05) and volume of subcortical normal appearing GM (NAGM) structures (r = .4; P≤ .04), but not WM lesions. CONCLUSIONS: Both NAWM and NAGM volumes are related to CI in MS. The results highlight once again the urgent need to develop pharmacological strategies protecting patients from widespread neurodegeneration as possible preventive strategies of CI development.

Discrimination of ADHD and reading disability in adults using the D-KEFS.

Attention deficit/hyperactivity disorder (ADHD) is posited to be the result of a deficit in executive functions (EFs). The presence of EF deficits in adults with ADHD is not consistent, and EF deficits are not unique to ADHD, thus adding a level of complexity to differential diagnoses. The current study used three measures of EF to discriminate between college-level adults diagnosed with ADHD and reading disability (RD). The RD group performed below ADHD on all EF tasks and logistic regression analyses demonstrated poor sensitivity and adequate specificity of the EF measures to categorize the clinical groups. Results suggest that clinicians should be cognizant of the limitations of measures of EF in the differential diagnosis of ADHD.

Quality and quantity of diffuse and focal white matter disease and cognitive disability of patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Using high-field magnetic resonance imaging (MRI), we investigated the relationships between white matter (WM) lesion volume (LV), normal-appearing WM (NAWM) normalized volume, WM-lesion and NAWM magnetization transfer ratios (MTRs), brain parenchyma fraction (BPF), and cognitive impairment (CI) in multiple sclerosis (MS). METHODS: Twenty-four patients and 24 healthy volunteers (age, sex, and years of education-matched) underwent a 3.0 Tesla (3T) scan and evaluation of depression, fatigue, and CI using the Minimal Assessment of Cognitive Function in MS (MACFIMS) battery. RESULTS: In this clinically relatively well-preserved cohort of patients (median score on the Expanded Disability Status Scale=1.5), CI was detected on Symbol Digit Modalities Test (SDMT), California Verbal Learning Test-II (CVLT-II), and Controlled Oral Word Association Test. MT data were available in 19 pairs on whom correlation analyses were performed. Associations were seen between SDMT and normalized NAWM volume (P=.034, r=.502), CVLT-II long delay and normalized NAWM volume (P=.012, r=.563), WM-LV (P=.024, r=.514), and BPF (P=.002, r=.666). CONCLUSIONS: The use of 3T MRI in a sample of clinically stable MS patients shows the importance of WM disease in hampering processing speed and word retrieval.

T1 cortical hypointensities and their association with cognitive disability in multiple sclerosis.

BACKGROUND: Neocortical lesions (NLs) largely contribute to the pathology of multiple sclerosis (MS), although their relevance in patients' disability remains unknown. OBJECTIVE: To assess the incidence of T(1) hypointense NLs by 3.0-Tesla magnetic resonance imaging (MRI) in patients with MS and examine neocortical lesion association with cognitive impairment. METHODS: In this case-control study, 21 MS patients and 21 age-, sex- and years of education-matched healthy volunteers underwent: (i) a neuropsychological examination rating cognitive impairment (Minimal Assessment of Cognitive Function in MS); (ii) a 3.0-Tesla MRI inclusive of an isotropic 1.0 mm(3) three-dimensional inversion prepared spoiled gradient-recalled-echo (3D-IRSPGR) image and T(1)- and T(2)-weighted images. Hypointensities on 3D-IRSPGR lying in the cortex, either entirely or partially were counted and association between NLs and cognitive impairment investigated. RESULTS: A total of 95 NLs were observed in 14 (66.7%) patients. NL+ patients performed poorer (p = 0.020) than NL-patients only on the delayed recall component of the California Verbal Learning Test. This difference lost statistical significance when a correction for white matter lesion volume was employed. CONCLUSIONS: Although T( 1) hypointense NLs may be present in a relatively high proportion of multiple sclerosis patients, the impact that they have in cognitive impairment is not independent from white matter disease.

Relationship of cortical atrophy to fatigue in patients with multiple sclerosis.

BACKGROUND: Fatigue is a common and disabling symptom of multiple sclerosis (MS). Previous studies reported that damage of the corticostriatothalamocortical circuit is critical in its occurrence. OBJECTIVE: To investigate the relationship between fatigue in MS and regional cortical and subcortical gray matter atrophy. DESIGN: Case-control study. SETTING: National Institutes of Health. PARTICIPANTS: Twenty-four patients with MS and 24 matched healthy volunteers who underwent 3.0-T magnetic resonance imaging and evaluations of fatigue (Modified Fatigue Impact Scale) and depression (Center for Epidemiologic Studies Depression Scale). MAIN OUTCOME MEASURES: Relationship between thalamic and basal ganglia volume, cortical thickness of frontal and parietal lobes, and, in patients, T2 lesion volume and normal-appearing white matter volume and the extent of fatigue. RESULTS: Patients were more fatigued than healthy volunteers (P = .04), while controlling for the effect of depression. Modified Fatigue Impact Scale score correlated with cortical thickness of the parietal lobe (r = -0.50, P = .01), explaining 25% of its variance. The posterior parietal cortex was the only parietal area significantly associated with the Modified Fatigue Impact Scale scores. CONCLUSIONS: Cortical atrophy of the parietal lobe had the strongest relationship with fatigue. Given the implications of the posterior parietal cortex in motor planning and integration of information from different sources, our preliminary results suggest that dysfunctions in higher-order aspects of motor control may have a role in determining fatigue in MS.