Neural alterations of fronto-striatal circuitry during reward anticipation in euthymic bipolar disorder

BACKGROUND

Bipolar disorder (BD), with the hallmark symptoms of elevated and depressed mood, is thought to be characterized by underlying alterations in reward-processing networks. However, to date the neural circuitry underlying abnormal responses during reward processing in BD remains largely unexplored. The aim of this study was to investigate whether euthymic BD is characterized by aberrant ventral striatal (VS) activation patterns and altered connectivity with the prefrontal cortex in response to monetary gains and losses.

METHOD

During functional magnetic resonance imaging 20 euthymic BD patients and 20 age-, gender- and intelligence quotient-matched healthy controls completed a monetary incentive delay paradigm, to examine neural processing of reward and loss anticipation. A priori defined regions of interest (ROIs) included the VS and the anterior prefrontal cortex (aPFC). Psychophysiological interactions (PPIs) between these ROIs were estimated and tested for group differences for reward and loss anticipation separately.

RESULTS

BD participants, relative to healthy controls, displayed decreased activation selectively in the left and right VS during anticipation of reward, but not during loss anticipation. PPI analyses showed decreased functional connectivity between the left VS and aPFC in BD patients compared with healthy controls during reward anticipation.

CONCLUSIONS

This is the first study showing decreased VS activity and aberrant connectivity in the reward-processing circuitry in euthymic, medicated BD patients during reward anticipation. Our findings contrast with research supporting a reward hypersensitivity model of BD, and add to the body of literature suggesting that blunted activation of reward processing circuits may be a vulnerability factor for mood disorders.

Influence of levothyroxine in augmentation therapy for bipolar depression on central serotonergic function

INTRODUCTION

Adjunctive treatment with supraphysiological doses of levothyroxine (L-T4) in bipolar depression shows promise, but the neurobiological mechanisms underlying clinical improvement are unknown. It has been postulated from animal studies that exogenous thyroid hormones may exert their modulatory effects in patients with affective disorders via an increase in serotonergic neurotransmission. Therefore, we investigated the loudness dependence of auditory evoked potentials (LDAEP) as a measure of central serotonergic activity and response to L-T4.

METHODS

This 6-week, double-blind, randomized, placebo-controlled study assessed the efficacy of L-T4 adjunctive to continuing treatment with mood stabilizer and/or antidepressant medication in 20 patients with bipolar depression. LDAEP was assessed before and after treatment with L-T4.

RESULTS

Scores of the Hamilton Depression Rating Scale and Montgomery Asberg Depression Rating Scale decreased significantly during the study. There was no difference in pre- and post-treatment LDAEP between the groups, and no correlation between LDAEP and psychometric measures in the course of the study.

DISCUSSION

The hypothesis of a relationship between response of augmentation therapy with levothyroxine in bipolar depression and serotonergic activity could not be confirmed.

Do rehabilitation tools cover the perspective of patients with rheumatoid arthritis? A focus group study using the ICF as a reference

BACKGROUND

Despite the advocated use of rehabilitation tools in clinical rehabilitation of with rheumatoid arthritis (RA) patients, little is known about the representation of the patient perspective in these tools.

AIM

Aim of the study was to explore the experiences of RA patients with rehabilitation and the coverage by rehabilitation tools.

DESIGN AND POPULATION

Qualitative focus group study with RA patients about experiences with rehabilitation.

SETTING

Rheumatology rehabilitation clinic of a Dutch university hospital.

METHODS

Focus groups were tape recorded and transcribed verbatim. From the meaningful units, concepts were extracted and linked to the International Classification of Functioning, Disability and Health (ICF). Rehabilitation tools validated for RA were identified using a structured literature search. Using the ICF as common framework, we determined for each concept identified in the focus groups the coverage by each rehabilitation tool.

RESULTS

Nineteen patients participated in 4 focus groups. Fifty-one concepts were identified in 368 meaningful units derived from the transcribed data. From the literature the ICF Core Sets for RA, Canadian Occupational Performance Measure, Rehabilitation Activities Profile and WHO Disability Assessment Schedule II were elected. The concepts from the focus groups were best covered by the ICF Core Sets (44 out of 51; 86%), followed by the WHODAS II (39%), RAP (35%) and COPM (16%).

CONCLUSION

With the exception of the ICF Core Sets for RA, current rehabilitation tools poorly cover the RA patients' perception on rehabilitation.

CLINICAL REHABILITATION IMPACT

The ICF Core Sets can serve as a checklist to guide multidisciplinary assessment, goal-setting and evaluation in RA rehabilitation.