Faculty Bibliography

Introduction: MS is a neurodegenerative, autoimmune disease associated with significant symptom burden such as fatigue, cognitive impairment, motor dysfunction, and depression. Thus, there is a need for therapeutic options for accessible symptom management. tDCS is an emerging neuromodulation treatment that delivers low amperage direct current (=2 mA) to targeted brain regions through scalp electrodes. tDCS is thought to lower the neuronal threshold required for action potentials and is often used to augment the benefit achieved through repetitive stimulation. Recent studies have demonstrated that at-home, remotely supervised tDCS (RS-tDCS) sessions can are successful in reducing fatigue in MS, studies have yet to elucidate the longevity of symptom benefit. Method(s): Participants with MS (N = 26) were recruited to complete a 20 sessions of RS-tDCS over a four-week period (5 sessions per week). We utilized a left anodal dorsolateral prefrontal cortex (DLPFC) montage as the target point for the treatment. The tDCS stimulation was at 2.0 mA. Surveys were completed at least one month following completion of the last RS-tDCS session asking whether any treatment benefit was achieved and whether it was sustained. Half the participants (N =13) received a sham/placebo stimulation, while the other half of the participants (N = 13) received the active stimulation. Both lab technicians and participants were blinded to the participant's conditions. Result(s): 65% of all participants reported treatment benefit. 92% (N =12) among the active participants and 38% (N = 5) among sham participants experienced benefit. The active group experienced a greater rate of benefit compared to the sham group (p<0.001). Furthermore, half of the participants assigned to the active condition that reported experiencing benefit also indicated that the benefit persisted (50%) and only a single participant who experienced benefit in the sham condition indicated that benefit persisted (20%). Conclusion(s): RS-tDCS results in symptom improvement in an MS cohort both immediately after the treatment finishes as well as, for many participants, after one month after treatment finishes. More clinical research should be done to elucidate the mechanism of long-lasting neural change due to tDCS that may help to improve MS symptoms. Longer studies should be done to examine whether self-reported benefit increases with number of sessions.

Multiple sclerosis (MS) is an autoimmune disease with high prevalence among populations of northern European ancestry. Past studies have shown that exposure to ultraviolet radiation could explain the difference in MS prevalence across the globe. In this study, we investigate whether the difference in MS prevalence could be explained by European genetic risk factors. We characterized the ancestry of MS-associated alleles using RFMix, a conditional random field parameterized by random forests, to estimate their local ancestry in the largest assembled admixed population to date, with 3,692 African Americans, 4,915 Asian Americans, and 3,777 Hispanics. The majority of MS-associated human leukocyte antigen (HLA) alleles, including the prominent HLA-DRB1*15:01 risk allele, exhibited cosmopolitan ancestry. Ancestry-specific MS-associated HLA alleles were also identified. Analysis of the HLA-DRB1*15:01 risk allele in African Americans revealed that alleles on the European haplotype conferred three times the disease risk compared to those on the African haplotype. Furthermore, we found evidence that the European and African HLA-DRB1*15:01 alleles exhibit single nucleotide polymorphism (SNP) differences in regions encoding the HLA-DRB1 antigen-binding heterodimer. Additional evidence for increased risk of MS conferred by the European haplotype were found for HLA-B*07:02 and HLA-A*03:01 in African Americans. Most of the 200 non-HLA MS SNPs previously established in European populations were not significantly associated with MS in admixed populations, nor were they ancestrally more European in cases compared to controls. Lastly, a genome-wide search of association between European ancestry and MS revealed a region of interest close to the ZNF596 gene on chromosome 8 in Hispanics; cases had a significantly higher proportion of European ancestry compared to controls. In conclusion, our study established that the genetic ancestry of MS-associated alleles is complex and implicated that difference in MS prevalence could be explained by the ancestry of MS-associated alleles.

BACKGROUND AND PURPOSE/OBJECTIVE:Pediatric-onset multiple sclerosis (POMS) is a demyelinating disorder with unique clinical challenges. A brief computer-administered cognitive screening battery measuring processing speed (Cogstate) and the Brief International Cognitive Assessment in MS (BICAMS) detect cognitive impairment in POMS. The neuroanatomic correlates of these deficits are incompletely understood. The purpose of this study is to define the neuroanatomic underpinnings of deficits identified with cognitive screening batteries in POMS. METHODS:Participants with POMS and age-matched healthy controls (HCs) were screened with Cogstate and BICAMS. Diffusion tensor imaging assessed region-wise and tractography-based fractional anisotropy (FA). RESULTS:The POMS (n = 15) and HC (n = 21) groups were matched on age (mean ages 17.9 ± 3.2 vs. 17.8 ± 3.3 years, respectively) and on an estimate of general intellectual functioning. The Cogstate composite revealed significant slowing in POMS relative to HCs (P = .004), but the BICAMS composite did not significantly distinguish the groups (P = .10). The Cogstate composite showed moderate-to-strong correlations with regional FA (r = -.67 to -.82) and significantly associated with uncinate fasciculus FA following multiple comparisons correction (P = .002) in POMS. However, the BICAMS composite measure showed only weak-to-moderate correlations with FA in POMS (r = -.19 to -.57), with none surviving multiple comparisons correction. CONCLUSIONS:Computer-administered measures of cognitive processing are particularly sensitive in POMS and are closely linked to white matter FA.

The prevalence of nocturia in patients with multiple sclerosis (MS) is high, ranging from 20.9% to 48.8% in this population. Its underlying pathophysiology is complex and different from the non-neurogenic population. In the MS population, the pathophysiology may involve neurogenic lower urinary tract dysfunction (NLUTD) such as detrusor overactivity (NDO), detrusor-sphincter dyssynergia, or detrusor underactivity resulting in reduced bladder capacity. Nocturnal polyuria is also a significant contributor to the pathogenesis of nocturia in MS patients and may be the result of specific mechanisms such as nocturnal hypertension through autonomic cardiovascular dysfunction or lack of diurnal variation of antidiuretic hormone production (ADH) due to demyelinating lesions of the spinal cord. Nocturia might be particularly burdensome in MS patients by contributing to fatigue, a common and highly debilitating symptom in this population. There is likely a complex and multidirectional relationship between nocturia, other sleep disorders, and fatigue in the MS population that has yet to be explored. The assessment of nocturia in MS should rely upon a thorough history and physical examination. Urinalysis should be done to rule out urinary tract infection, a frequency-volume chart might help elucidating the underlying mechanisms, and post-void residual volume may be of interest to screen for urinary retention that could be asymptomatic in MS patients. Other tests such as urodynamics or polysomnography are indicated in selected patients. The treatment should be tailored to the underlying cause. The first steps involve behavioral interventions and treatment of cofactors. When possible, the predominant mechanism should be addressed first. In case of predominant NDO, antimuscarinics and beta-3 agonists should be offered as a first-line treatment and intradetrusor injections of botulinum toxin as a second-line treatment. In cases of incomplete bladder emptying, clean-intermittent self-catheterization is often used as part of multiple other interventions. In cases of nocturnal polyuria, desmopressin may be offered, inclusive of use of newer formulations (desmopressin acetate nasal spray, desmopressin orally disintegrated tablet) in countries where they are approved.