Faculty Bibliography

Introduction: Cognitive impairment is common and often disabling in multiple sclerosis (MS), but the risk factors and mechanisms underlying cognitive decline remain poorly understood. Pediatric MS (MS onset < 18 years of age) is unique due to the demyelinating process occurring in the context of development.
Objective(s): To compare cognitive functions in newly diagnosed patients with either adult- or pediatric-onset MS (AOMS vs. POMS).
Aim(s): To test performance in newly diagnosed MS patients using the Symbol Digit Modalities Test (SDMT) and a computer-based measure sensitive to processing speed deficits (Cogstate).
Method(s): As part of an ongoing multi-center longitudinal cognition trial, AOMS and POMS participants were recruited from outpatient visits and matched by years of disease. At the baseline evaluation, all participants were administered the Wide Range Achievement Test-4 (WRAT-4), the SDMT and the Cogstate Brief Battery, which includes three measures of information processing speed tasks:simple (DET) and choice (IDN) reaction time and working memory (ONB). Cogstate scores were converted to z-scores and then averaged for one composite z-score.
Result(s): A total of n=64 participants completed baseline assessments with n= 32 in the AOMS group (mean age 33.36 ?+/- 5.82) and n= 32 in the POMS group (mean age 11.31 ?+/- 3.64). All participants had relapsing remitting disease and the groups were matched for disease duration (4.91 ?+/- 3.05 years for AOMS vs. 6.38 ?+/- 3.54 for POMS). The POMS group had higher estimated premorbid IQ (WRAT-4 reading 112.7 ?+/- 18.5 vs. 105.4 ?+/- 13.4), though the result did not reach significance (p=0.07). Neither group's cognitive performances fell into the impaired range relative to age-normative means. However, the AOMS compared to the POMS group consistently performed significantly worse on the SDMT (mean z-score -0.26 ?+/- 1.15 for AOMS vs. 0.68 ?+/- 1.53 for POMS, p=0.01) and slower on the Cogstate composite (mean z-score of -1.04 ?+/- 1.09 for AOMS vs. 0.35 ?+/- 1.15 for POMS, p=0.04). Estimated premorbid IQ was correlated with SDMT, but not Cogstate performance (r=0.56 p=0.001 and r=0.13 p=0.35, respectively). Age of disease onset was significantly negatively correlated with cognitive processing (SDMT: r= -0.32, p= 0.01 and Cogstate DET: r= -0.33, p=0.02), further indicating that older age of onset is associated with greater cognitive impairment.
Conclusion(s): Adult MS is associated with larger cognitive involvement than pediatric MS

Introduction: Cognitive impairment represents a frequent and troubling symptom of multiple sclerosis (MS) in need of treatment options. Transcranial direct current stimulation (tDCS) uses scalpbased electrodes to pass mild electrical current (< 4mA) through target cortical brain regions and is a safe and well-tolerated treatment. We have developed a protocol to deliver remotely supervised cognitive remediation paired with tDCS to individuals with MS at home.
Objective(s): To test whether at-home cognitive remediation augmented with tDCS will lead to improved training outcomes in MS.
Aim(s): Cognitive processing speed was assessed at baseline and study end by the Cogstate Brief Battery. Age normative z scores were computed for the Cogstate Brief Battery scores, with outcome measured by change in the average z score of information processing assessments.
Method(s): MS participants with cognitive impairment were recruited and randomized to complete 40 sessions of either active or sham tDCS paired with either adaptive or non-adaptive cognitive training (aCT or nCT). Training was completed at home using study-provided equipment and remotely supervised via videoconference using our established probed (RS-tDCS). Training was 20 minutes in duration and was completed five times a week (M-F) for approximately eight weeks. Participants were blinded and received active (2.5mA) or sham stimulation and cognitive training simultaneously during each session.
Result(s): To date, n=19 MS participants have successfully complete the 40 session training program at home: n=6 in active/aCT, n=8 in Sham/aCT, and n=5 in active/nCT. Mean age was 49+/-15 years of age and mean years of education was 16.5+/-2.1. The majority of participants had the RRMS subtype (63%, with 11% PPMS, and 26% SPMS). The participants were matched on cognitive status as measured by the symbol digit modality test (ANOVA p=0.09). tDCS and the cognitive training were uniformly well tolerated with no safety concerns. At the group level, all three groups showed improvement from baseline (0.75, 0.56, 0.59 z-score improvement for each condition respectively), indicating that both tDCS and aCT can be of benefit. Further, as predicted, the active tDCS paired with aCT experienced the greatest benefit (Cohen's d = 0.51).
Conclusion(s): Our telerehabiltiation protocol allows for participants to receive extended cognitive training paired with tDCS at home, resulting in improved outcomes from cognitive remediation

Introduction: Pediatric onset multiple sclerosis (POMS) is a demyelinating disorder occurring in the context of neurodevelopment with unique clinical challenges due to the potential for disease-related cognitive impairment. A brief cognitive screening battery of computer administered measures of processing speed (Cogstate) and the Brief International Cognitive Assessment in MS (BICAMS) detects cognitive impairment in POMS. However, the neuroanatomic correlates of these deficits are incompletely understood. We have sought to define the neuroimaging correlates of deficits identified with a cognitive screening battery in POMS.
Objective(s): To test the links between white matter integrity and cognitive functioning in pediatric MS patients and matched healthy controls.
Aim(s): Participants cognitive performance as measured by the BICAMS and Cogstate assessments was compared to magnetic resonance imaging (MRI) outcomes.
Method(s): Participants with POMS and age-matched healthy controls (HC) completed cognitive screening with Cogstate and the BICAMS along with 64-direction MRI based diffusion tensor imaging (DTI).
Result(s): The POMS group (n= 15, mean age 17.9+/-3.2 years) compared to the HC group (n= 21, mean age 17.8+/-3.3 years) were significantly slower on a composite Cogstate score (p=0.004), but the groups did not significantly differ using a composite BICAMS score (p = 0.10). The POMS group also presented with increased fractional anisotropy (FA) in the thalamus (p=0.01) and reduced FA in the corpus callosum (p=0.05) and temporal lobe white matter (p=0.03) relative to HCs. Controlling for age and sex within groups, the measured slowed processing speed (Cogstate composite) significantly negatively correlated with regional fractional anisotropy (FA) in the corpus callosum, temporal and occipital lobe white matter, and in the tractography-based uncinate fasciculus in the POMS sample (p=0.002 to 0.025), whereas the reduced verbal learning (RAVLT) was significantly negatively correlated with thalamic FA (p = 0.046). Of these effects, only the relationship between the Cogstate composite and temporal lobe FA was significant in the HCs (p=0.013).
Conclusion(s): Computer administered measures of cognitive processing speed are particularly sensitive to slowing in POMS and are closely linked to MRI diffusion measures

BACKGROUND:Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has been shown to improve common symptoms of neurological disorders like depressed mood, fatigue, motor deficits and cognitive dysfunction. tDCS requires daily treatment sessions in order to be effective. We developed a remotely supervised tDCS (RS-tDCS) protocol for participants with multiple sclerosis (MS) to increase accessibility of tDCS, reducing clinician, patient, and caregiver burden. The goal of this protocol is to facilitate home use for larger trials with extended treatment periods. In this study we determine the generalizability of RS-tDCS paired with cognitive training (CT) by testing its feasibility in participants with Parkinson's disease (PD). METHODS:Following the methods in our MS protocol development, we enrolled sixteen participants (n = 12 male, n = 4 female; mean age 66 years) with PD to complete ten open-label sessions of RS-tDCS paired with CT (2.0 mA × 20 min) at home under the remote supervision of a trained study technician. Tolerability data were collected before, during, and after each individual session. Baseline and follow-up measures included symptom inventories (fatigue and sleep) and cognitive assessments. RESULTS:RS-tDCS was feasible and tolerable for patients with PD, with at-home access leading to high protocol compliance. Side effects were mostly limited to mild sensations of transient itching and burning under the electrode sites. Similar to prior finding sin MS, we found preliminary efficacy for improvement of fatigue and cognitive processing speed in PD. CONCLUSIONS:RS-tDCS paired with CT is feasible for participants with PD to receive at home treatment. Signals of benefit for reduced fatigue and improved cognitive processing speed are consistent across the PD and MS samples. RS-tDCS can be generalized to provide tDCS to a range of patients with neurologic disorders for at-home rehabilitation. TRIAL REGISTRATION/BACKGROUND:ClinicalTrials.gov Identifier: NCT02746705 . Registered April 21st 2016.