The relation of hippocampal subfield volumes to verbal episodic memory measured by the California Verbal Learning Test II in healthy adults.

Total hippocampal volume has previously been shown to correlate with performance on tests for verbal episodic memory. However, there are sparse evidence on how hippocampal subfield volumes are related to verbal episodic memory in healthy adults. The present study investigated the association between volumes of separate hippocampal subfields and verbal episodic memory performance in healthy volunteers. Forty-seven participants (31 females) between 20-71 years age underwent testing with the California Verbal Learning Test II (CVLT II), and the Wechsler Abbreviated Scale of Intelligence (WASI) to obtain an estimate of cognitive functioning. T1-weighted MR images were obtained after cognitive testing, and volumetric estimates adjusted for age and estimated total intracranial volume were calculated in the FreeSurfer 6.0 software suite for cerebral -and hippocampal structures. The sample performed within the statistical normal range on both CVLT II and WASI. Significant correlations adjusted for multiple testing were found between CVLT II subtests of total learning, free immediate recall and free delayed recall and volumes of the left Cornu Ammonis (CA) 1-4 subfields. There were no significant correlations between right hippocampal subfields and CVLT II performance, and no significant correlation between WASI results and hippocampal subfields. The present results suggest that better verbal episodic memory measured by the CVLT II is associated with relative larger volumes of specific left CA hippocampal subfields in healthy adults. Due to the small sample size and large age-span of the participants, the present findings are preliminary and should be confirmed in larger samples.

[Transcranial direct current stimulation for chronic pain]. / Transkranial likestrømsstimulering ved kroniske smerter.

BACKGROUND: Transcranial Direct Current Stimulation (tDCS) is a non-invasive method for neuromodulation. By changing the neurons' resting membrane potential, the method can alter the activity in areas of the brain. We therefore wished to review randomised controlled trials (RCTs) that investigate the treatment effect of tDCS on chronic pain. EVIDENCE: We undertook a search in PubMed with the search terms «transcranial direct current stimulation¼ and «pain¼, with «randomized controlled trial¼ as a filter. RESULTS: Five randomised, controlled trials that used quantitative outcome measures for pain were identified. The studies focused on strongly varying groups of patients suffering from pain. The results from some of the studies showed that stimulation with the aid of tDCS led to a significantly lower level of pain, but seen as a whole, the results were not conclusive. INTERPRETATION: The method should be further investigated in studies that include clearly defined groups of patients suffering from pain, as well as a larger number of participants, before implementation of the method is considered as a treatment option for chronic pain.