Neuropsychological testing of cognitive impairment in euthymic bipolar disorder: an individual patient data meta-analysis.

OBJECTIVE: An association between bipolar disorder and cognitive impairment has repeatedly been described, even for euthymic patients. Findings are inconsistent both across primary studies and previous meta-analyses. This study reanalysed 31 primary data sets as a single large sample (N = 2876) to provide a more definitive view. METHOD: Individual patient and control data were obtained from original authors for 11 measures from four common neuropsychological tests: California or Rey Verbal Learning Task (VLT), Trail Making Test (TMT), Digit Span and/or Wisconsin Card Sorting Task. RESULTS: Impairments were found for all 11 test-measures in the bipolar group after controlling for age, IQ and gender (Ps ≤ 0.001, E.S. = 0.26-0.63). Residual mood symptoms confound this result but cannot account for the effect sizes found. Impairments also seem unrelated to drug treatment. Some test-measures were weakly correlated with illness severity measures suggesting that some impairments may track illness progression. CONCLUSION: This reanalysis supports VLT, Digit Span and TMT as robust measures of cognitive impairments in bipolar disorder patients. The heterogeneity of some test results explains previous differences in meta-analyses. Better controlling for confounds suggests deficits may be smaller than previously reported but should be tracked longitudinally across illness progression and treatment.

The relationship of serum cobalamin to methylmalonic acid concentrations and clinical variables in cats.

BACKGROUND: Serum cobalamin concentration [CBL] suggests CBL deficiency in cats but serum methylmalonic acid concentration [MMA] more accurately indicates CBL deficiency. OBJECTIVE: To examine the ability of [CBL] to predict CBL deficiency defined by increased [MMA], and relationships of [CBL] and [MMA] with select clinical and clinicopathological variables. ANIMALS: One hundred sixty-three client-owned cats with [CBL] measurements, 114 cats with simultaneous [MMA] measurements; 88 cats with medical information. METHODS: Prospectively collected [CBL] and [MMA] were compared using scatter plots, receiver operating characteristic and correlative analyses with historical [CBL] thresholds and those identified in the study. [CBL] and [MMA] were compared retrospectively to specific clinical and clinicopathological variables. RESULTS: [CBL] correlated negatively with [MMA] (τ = -0.334, P < .0001). [MMA] ≥ 1,343 nmol/L identified CBL deficiency. [CBL] = 209 pg/mL optimized sensitivity (0.51), specificity (0.96), PPV (0.89), and NPV (0.74) for detecting [MMA] ≥ 1,343 nmol/L. Prevalence of CBL deficiency was 42% (48/114) when defined by [MMA] ≥ 1,343 nmol/L versus 23% (27/114) by [CBL] ≤ 209 pg/mL. Unexpectedly, 23 and 45% of 48 cats with [MMA] ≥ 1,343 nmol/L had [CBL] > 900 pg/mL and 290 pg/mL (historical thresholds). [CBL] correlated with mean corpuscular volume (τ = -0.199, P = .013) and [MMA] with hematocrit (τ = -0.28, P = .006). CONCLUSIONS AND CLINICAL IMPORTANCE: Cobalamin deficiency ([MMA] ≥ 1,343 nmol/L) occurred in 42% of cats and is predicted with high specificity by [CBL] ≤ 209 pg/mL. CBL status correlates with microcytosis and anemia. Discordance between [CBL] and [MMA] cautions against relying on any single marker for determining CBL status.

An exploratory study of the neural mechanisms of decision making in compulsive hoarding.

BACKGROUND: Prior studies have suggested unique patterns of neural activity associated with compulsive hoarding. However, to date no studies have examined the process of making actual decisions about whether to keep or discard possessions in patients with hoarding symptoms. An increasing body of clinical data and experimental psychopathology research suggests that hoarding is associated with impaired decision making; therefore, it is important to understand the neural underpinnings of decision-making abnormalities in hoarding patients. METHOD: Twelve adult patients diagnosed with compulsive hoarding, 17% of whom also met criteria for obsessive-compulsive disorder (OCD), and 12 matched healthy controls underwent functional magnetic resonance imaging (fMRI) while making decisions about whether or not to discard personal paper items (e.g. junk mail) brought to the laboratory as well as control items that did not belong to them. Items were either saved or destroyed following each decision. RESULTS: When deciding about whether to keep or discard personal possessions, compulsive hoarding participants displayed excessive hemodynamic activity in lateral orbitofrontal cortex and parahippocampal gyrus. Among hoarding participants, decisions to keep personal possessions were associated with greater activity in superior temporal gyrus, middle temporal gyrus, medial frontal gyrus, anterior cingulate cortex, precentral gyrus, and cerebellum than were decisions to discard personal possessions. CONCLUSIONS: These results provide partial support for an emerging model of compulsive hoarding based on complications of the decision-making process. They also suggest that compulsive hoarding may be characterized by focal deficits in the processing of reward and changes in reward contingencies, particularly when these are perceived to be punishing.