A multimodal neuroimaging study of brain abnormalities and clinical correlates in post treatment Lyme disease.

Lyme disease is the most common vector-borne infectious disease in the United States. Post-treatment Lyme disease (PTLD) is a condition affecting 10-20% of patients in which symptoms persist despite antibiotic treatment. Cognitive complaints are common among those with PTLD, suggesting that brain changes are associated with the course of the illness. However, there has been a paucity of evidence to explain the cognitive difficulties expressed by patients with PTLD. This study administered a working memory task to a carefully screened group of 12 patients with well-characterized PTLD and 18 healthy controls while undergoing functional MRI (fMRI). A subset of 12 controls and all 12 PTLD participants also received diffusion tensor imaging (DTI) to measure white matter integrity. Clinical variables were also assessed and correlated with these multimodal MRI findings. On the working memory task, the patients with PTLD responded more slowly, but no less accurately, than did controls. FMRI activations were observed in expected regions by the controls, and to a lesser extent, by the PTLD participants. The PTLD group also hypoactivated several regions relevant to the task. Conversely, novel regions were activated by the PTLD group that were not observed in controls, suggesting a compensatory mechanism. Notably, three activations were located in white matter of the frontal lobe. DTI measures applied to these three regions of interest revealed that higher axial diffusivity correlated with fewer cognitive and neurological symptoms. Whole-brain DTI analyses revealed several frontal lobe regions in which higher axial diffusivity in the patients with PTLD correlated with longer duration of illness. Together, these results show that the brain is altered by PTLD, involving changes to white matter within the frontal lobe. Higher axial diffusivity may reflect white matter repair and healing over time, rather than pathology, and cognition appears to be dynamically affected throughout this repair process.

Characterization of basal ganglia volume changes in the context of HIV and polysubstance use.

HIV and psychoactive substances can impact the integrity of the basal ganglia (BG), a neural substrate of cognition, motor control, and reward-seeking behaviors. This study assessed BG gray matter (GM) volume as a function of polysubstance (stimulant and opioid) use and HIV status. We hypothesized that comorbid polysubstance use and HIV seropositivity would alter BG GM volume differently than would polysubstance use or HIV status alone. We collected structural MRI scans, substance use history, and HIV diagnoses. Participants who had HIV (HIV +), a history of polysubstance dependence (POLY +), both, or neither completed assessments for cognition, motor function, and risk-taking behaviors (N = 93). All three clinical groups showed a left-lateralized pattern of GM reduction in the BG relative to controls. However, in the HIV + /POLY + group, stimulant use was associated with increased GM volume within the globus pallidus and putamen. This surpassed the effects from opioid use, as indicated by decreased GM volume throughout the BG in the HIV-/POLY + group. Motor learning was impaired in all three clinical groups, and in the HIV + /POLY + group, motor learning was associated with increased caudate and putamen GM volume. We also observed associations between BG GM volume and risk-taking behaviors in the HIV + /POLY- and HIV-/POLY + groups. The effects of substance use on the BG differed as a function of substance type used, HIV seropositivity, and BG subregion. Although BG volume decreased in association with HIV and opioid use, stimulants can, inversely, lead to BG volume increases within the context of HIV.

Diagnostic utility of the subjective peripheral neuropathy screen in HIV-infected persons with peripheral sensory polyneuropathy.

A retrospective analysis of the Johns Hopkins University HIV neurology database was performed to assess the sensitivity and specificity of the Subjective Peripheral Neuropathy Screen (SPNS) for detecting HIV-associated neuropathies. The SPNS, a 3-item scale that evaluates lower extremity neuropathic symptoms, was administered to 75 patients from the HIV neurology outpatient clinic. Patients graded the severity of each symptom on a scale of 1 to 10, and the sensitivity, specificity, and diagnostic efficiency of the SPNS were calculated for each symptom. The results showed that the SPNS had a sensitivity of 47%, a specificity of 83%, a positive predictive value of 70%, and a diagnostic efficacy of 67%. The SPNS appears to be a useful screening tool for HIV-associated sensory neuropathies; it has a high specificity and a good positive predictive value.

Construct validity of the relationship profile test: a self-report measure of dependency-detachment.

This study evaluated the construct validity of the Relationship Profile Test (RPT; Bornstein & Languirand, 2003), a 30-item self-report measure of dependency-detachment that yields three subscale scores: (a) destructive overdependence, (b) dysfunctional detachment, and (c) healthy dependency. Scores on the RPT subscales generally showed the expected patterns of intercorrelations and gender differences, and comparison of RPT scores with scores on other tests supported the convergent and discriminant validity of each RPT subscale. Results of internal and retest reliability analyses were generally supportive as well, and suggested that the three RPT subscales assess aspects of the traits they purport to measure