The role of the thalamus and hippocampus in episodic memory performance in patients with multiple sclerosis.

BACKGROUND: Episodic memory loss is one of the most common cognitive symptoms in patients with multiple sclerosis (MS), but the pathophysiology of this symptom remains unclear. Both the hippocampus and thalamus have been implicated in episodic memory and show regional atrophy in patients with MS. OBJECTIVE: In this work, we used functional magnetic resonance imaging (fMRI) during a verbal episodic memory task, lesion load, and volumetric measures of the hippocampus and thalamus to assess the relative contributions to verbal and visual-spatial episodic memory. METHODS: Functional activation, lesion load, and volumetric measures from 32 patients with MS and 16 healthy controls were used in a predictive analysis of episodic memory function. RESULTS: After adjusting for disease duration, immediate recall performance on a visual-spatial episodic memory task was significantly predicted by hippocampal volume ( p < 0.003). Delayed recall on the same task was significantly predicted by volume of the left thalamus ( p < 0.003). For both memory measures, functional activation of the thalamus during encoding was more predictive than that of volume measures ( p < 0.002). CONCLUSION: Our results suggest that functional activation may be useful as a predictive measure of episodic memory loss in patients with MS.

Activation volume vs BOLD signal change as measures of fMRI activation - Its impact on GABA - fMRI activation correlation.

PURPOSE: To explore the relative robustness of functional MRI (fMRI) activation volume and blood oxygen level-dependent (BOLD) signal change as fMRI metric, and to study the effect of relative robustness on the correlation between fMRI activation and cortical gamma amino butyric acid (GABA) in healthy controls and patients with multiple sclerosis (MS). METHODS: fMRI data were acquired from healthy controls and patients with MS, with the subjects peforming self paced bilateral finger tapping in block design. GABA spectroscopy was performed with voxel placed on the area of maximum activation during fMRI. Activation volume and BOLD signal changes at primary motor cortex (M1), as well as GABA concentration were calculated for each patient. RESULTS: Activation volume correlated with BOLD signal change in healthy controls, but no such correlation was observed in patients with MS. This difference was likely the result of higher intersubject noise variance in the patient population. GABA concentration correlated with M1 activation volume in patients but not in controls, and did not correlate with any fMRI metric in patients or controls. CONCLUSION: Our data suggest that activation volume is a more robust measure than BOLD signal change in a group with high intersubject noise variance as in patients with MS. Additionally, this study demonstrated difference in correlation behavior between GABA concentration and the 2 fMRI metrics in patients with MS, suggesting that GABA - activation volume correlation is more appropriate measure in the patient group.

In vivo magnetic resonance spectroscopy measurement of gray-matter and white-matter gamma-aminobutyric acid concentration in sensorimotor cortex using a motion-controlled MEGA point-resolved spectroscopy sequence.

Gamma-aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the brain. Understanding the GABA concentration, in vivo, is important to understand normal brain function. Using MEGA point-resolved spectroscopy sequence with interleaved water scans to detect subject motion, GABA level of sensorimotor cortex was measured using a voxel identified from a functional magnetic resonance imaging scan. The GABA level in a 20×20×20-mm(3) voxel consisting of 37%±7% gray matter, 52%±12% white matter and 11%±8% cerebrospinal fluid in the sensorimotor region was measured to be 1.43±0.48 mM. In addition, using linear regression analysis, GABA concentrations within gray and white matter were calculated to be 2.87±0.61 and 0.33±0.11 mM, respectively.

Effects of meditation on pain and quality of life in multiple sclerosis and peripheral neuropathy: a pilot study.

The objective of this study was to determine whether meditation affects pain and quality of life in people with multiple sclerosis (MS) and peripheral neuropathy (PN). A total of 22 patients (10 with MS, 12 with PN) participated in a weekly meditation class over a 2-month period. A total of 18 controls (7 with MS, 11 with PN) received standard care. Primary outcome assessments were based on the 36-item Short Form Health Status Survey (SF-36) and a visual analogue scale (VAS) for pain at baseline and at 2 months. Secondary outcome measures included the Neuropathy Impairment Score (NIS) for PN patients and the Patient-Determined Disease Steps (PDDS) questionnaire and 5-item Modified Fatigue Impact Scale (MFIS-5) for MS patients. After 2 months, study participants who practiced meditation reported an improvement in pain on the VAS (P = .035 combined group), summed physical health scores on the SF-36 (P = .011 MS, P = .014 PN), summed mental health scores (P = .02 combined group), vitality (P = .005 combined group), and physical role (P = .003 combined group). A significant improvement was also observed for bodily pain (P = .031) in MS patients. In contrast, no significant differences before and after the intervention were observed for controls. Regarding the secondary measure of fatigue, improved scores for the cognitive and psychosocial components of the MFIS were noted in MS patients in the intervention group (P = .037, P = .032). No statistically significant changes were observed in the NIS for PN patients or in PDDS scores for MS patients. Meditation may be helpful in reducing pain and improving quality of life in patients with MS and PN. The lack of changes seen in mobility (MS) and sensorimotor deficits (PN) suggests that meditation may not affect the overall clinical course.