Jody Goldstein

Contrasting gray and white matter changes in preclinical Huntington disease An MRI study

Background: In Huntington disease (HD), substantial striatal atrophy precedes clinical motor symptoms. Accordingly, neuroprotection should prevent major cell loss before such symptoms arise. To evaluate neuroprotection, biomarkers such as MRI measures are needed. This requires first establishing the best imaging approach. Methods: Using a cross-sectional design, we acquired T1-weighted and diffusion-weighted scans in 39 preclinical (pre-HD) individuals and 25 age-matched controls. T1-weighted scans were analyzed with gross whole-brain segmentation and voxel-based morphometry. Analysis of diffusion-weighted scans used skeleton-based tractography. For all imaging measures, we compared pre-HD and control groups and within the pre-HD group we examined correlations with estimated years to clinical onset. Results: Pre-HD individuals had lower gross gray matter (GM) and white matter (WM) volume. Voxel-wise analysis demonstrated local GM volume loss, most notably in regions consistent with basal ganglia–thalamocortical pathways. By contrast, pre-HD individuals showed widespread reductions in WM integrity, probably due to a loss of axonal barriers. Both GM and WM imaging measures correlated with estimated years to onset. Conclusions: Using automated, observer-independent methods, we found that GM loss in pre-HD was regionally specific, while WM deterioration was much more general and probably the result of demyelination rather then axonal degeneration. These findings provide important information about the nature, relative staging, and topographic specificity of brain changes in pre-HD and suggest that combining GM and WM imaging may be the best biomarker approach. The empirically derived group difference images from this study are provided as regions-of-interest masks for improved sensitivity in future longitudinal studies.

A randomized, double-blind, placebo-controlled trial of pridopidine in Huntington's disease

We examined the effects of 3 dosages of pridopidine, a dopamine‐stabilizing compound, on motor function and other features of Huntingtons disease, with additional evaluation of its safety and tolerability. This was a randomized, double‐blind, placebo‐controlled trial in outpatient neurology clinics at 27 sites in the United States and Canada. Two hundred twenty‐seven subjects enrolled from October 24, 2009, to May 10, 2010. The intervention was pridopidine, either 20 (n=56), 45 (n=55), or 90 (n=58) mg daily for 12 weeks or matching placebo (n=58). The primary outcome measure was the change from baseline to week 12 in the Modified Motor Score, a subset of the Unified Huntingtons Disease Rating Scale Total Motor Score. Measures of safety and tolerability included adverse events and trial completion on the assigned dosage. After 12 weeks, the treatment effect (relative to placebo, where negative values indicate improvement) of pridopidine 90 mg/day on the Modified Motor Score was −1.2 points (95% confidence interval [CI], −2.5 to 0.1 points; P = .08). The effect on the Total Motor Score was −2.8 points (95% CI, −5.4 to −0.1 points; nominal P = .04). No significant effects were seen in secondary outcome measures with any of the active dosages. Pridopidine was generally well tolerated. Although the primary analysis did not demonstrate a statistically significant treatment effect, the overall results suggest that pridopidine may improve motor function in Huntingtons disease. The 90 mg/day dosage appears worthy of further study. Pridopidine was well tolerated.

Effect of Deutetrabenazine on Chorea Among Patients With Huntington Disease: A Randomized Clinical Trial

IMPORTANCE Deutetrabenazine is a novel molecule containing deuterium, which attenuates CYP2D6 metabolism and increases active metabolite half-lives and may therefore lead to stable systemic exposure while preserving key pharmacological activity. OBJECTIVE To evaluate efficacy and safety of deutetrabenazine treatment to control chorea associated with Huntington disease. DESIGN, SETTING, AND PARTICIPANTS Ninety ambulatory adults diagnosed with manifest Huntington disease and a baseline total maximal chorea score of 8 or higher (range, 0-28; lower score indicates less chorea) were enrolled from August 2013 to August 2014 and randomized to receive deutetrabenazine (n = 45) or placebo (n = 45) in a double-blind fashion at 34 Huntington Study Group sites. INTERVENTIONS Deutetrabenazine or placebo was titrated to optimal dose level over 8 weeks and maintained for 4 weeks, followed by a 1-week washout. MAIN OUTCOMES AND MEASURES Primary end point was the total maximal chorea score change from baseline (the average of values from the screening and day-0 visits) to maintenance therapy (the average of values from the week 9 and 12 visits) obtained by in-person visits. This study was designed to detect a 2.7-unit treatment difference in scores. The secondary end points, assessed hierarchically, were the proportion of patients who achieved treatment success on the Patient Global Impression of Change (PGIC) and on the Clinical Global Impression of Change (CGIC), the change in 36-Item Short Form- physical functioning subscale score (SF-36), and the change in the Berg Balance Test. RESULTS Ninety patients with Huntington disease (mean age, 53.7 years; 40 women [44.4%]) were enrolled. In the deutetrabenazine group, the mean total maximal chorea scores improved from 12.1 (95% CI, 11.2-12.9) to 7.7 (95% CI, 6.5-8.9), whereas in the placebo group, scores improved from 13.2 (95% CI, 12.2-14.3) to 11.3 (95% CI, 10.0-12.5); the mean between-group difference was -2.5 units (95% CI, -3.7 to -1.3) (P < .001). Treatment success, as measured by the PGIC, occurred in 23 patients (51%) in the deutetrabenazine group vs 9 (20%) in the placebo group (P = .002). As measured by the CGIC, treatment success occurred in 19 patients (42%) in the deutetrabenazine group vs 6 (13%) in the placebo group (P = .002). In the deutetrabenazine group, the mean SF-36 physical functioning subscale scores decreased from 47.5 (95% CI, 44.3-50.8) to 47.4 (44.3-50.5), whereas in the placebo group, scores decreased from 43.2 (95% CI, 40.2-46.3) to 39.9 (95% CI, 36.2-43.6), for a treatment benefit of 4.3 (95% CI, 0.4 to 8.3) (P = .03). There was no difference between groups (mean difference of 1.0 unit; 95% CI, -0.3 to 2.3; P = .14), for improvement in the Berg Balance Test, which improved by 2.2 units (95% CI, 1.3-3.1) in the deutetrabenazine group and by 1.3 units (95% CI, 0.4-2.2) in the placebo group. Adverse event rates were similar for deutetrabenazine and placebo, including depression, anxiety, and akathisia. CONCLUSIONS AND RELEVANCE Among patients with chorea associated with Huntington disease, the use of deutetrabenazine compared with placebo resulted in improved motor signs at 12 weeks. Further research is needed to assess the clinical importance of the effect size and to determine longer-term efficacy and safety. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01795859.

Evaluating imaging biomarkers for neurodegeneration in pre-symptomatic Huntington's disease using machine learning techniques

The development of MRI measures as biomarkers for neurodegenerative disease could prove extremely valuable for the assessment of neuroprotective therapies. Much current research is aimed at developing such biomarkers for use in people who are gene-positive for Huntingtons disease yet exhibit few or no clinical symptoms of the disease (pre-HD). We acquired structural (T1), diffusion weighted and functional MRI (fMRI) data from 39 pre-HD volunteers and 25 age-matched controls. To determine whether it was possible to decode information about disease state from neuroimaging data, we applied multivariate pattern analysis techniques to several derived voxel-based and segmented region-based datasets. We found that different measures of structural, diffusion weighted, and functional MRI could successfully classify pre-HD and controls using support vector machines (SVM) and linear discriminant analysis (LDA) with up to 76% accuracy. The model producing the highest classification accuracy used LDA with a set of six volume measures from the basal ganglia. Furthermore, using support vector regression (SVR) and linear regression models, we were able to generate quantitative measures of disease progression that were significantly correlated with established measures of disease progression (estimated years to clinical onset, derived from age and genetic information) from several different neuroimaging measures. The best performing regression models used SVR with neuroimaging data from regions within the grey matter (caudate), white matter (corticospinal tract), and fMRI (insular cortex). These results highlight the utility of machine learning analyses in addition to conventional ones. We have shown that several neuroimaging measures contain multivariate patterns of information that are useful for the development of disease-state biomarkers for HD.

Cognitive and Functional Decline in Huntington's Disease: Dementia Criteria Revisited

The importance of designating criteria for diagnosing dementia lies in its implications for clinical treatment, research, caregiving, and decision‐making. Dementia diagnosis in Huntingtons disease (HD) is often based on criteria developed for Alzheimers disease requiring memory loss. However, it is likely that other cognitive deficits contribute to functional impairment in HD before memory declines. The goal is to identify cognitive deficits that contribute to functional impairment to support dementia criteria that reflect HD neuropathology. Eighty‐four HD mutation‐positive subjects completed neuropsychological tests and the Unified Huntingtons Disease Rating Scale Functional Independence Scale (FIS). Functional impairment was defined as 80 or below on the FIS. Speed of processing, initiation, and attention measures accounted for 70.0% of the variance in FIS ratings (linear regression) and correctly classified 91.7% of subjects as functionally impaired or intact (logistic regression). Measures of memory, motor impairment except dysarthria, neuroleptic use, and depressed mood did not improve prediction. A definition of HD dementia that includes cognitive impairment in at least two areas of cognition but does not require a memory deficit, in the context of impaired functional abilities and a deteriorating course, more accurately reflects HD neuropathology and could lead to improved research methods and patient care.

Cognitive performance on the mini-mental state examination and the montreal cognitive assessment across the healthy adult lifespan.

Objective:We sought to compare age-related performance on the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) across the adult lifespan in an asymptomatic, presumably normal, sample. Background:The MMSE is the most commonly used brief cognitive screening test; however, the MoCA may be better at detecting early cognitive dysfunction. Methods:We gave the MMSE and MoCA to 254 community-dwelling participants ranging in age from 20 to 89, stratified by decade, and we compared their scores using the Wilcoxon signed rank test. Results:For the total sample, the MMSE and MoCA differed significantly in total scores as well as in visuospatial, language, and memory domains (for all of these scores, P<0.001). Mean MMSE scores declined only modestly across the decades; mean MoCA scores declined more dramatically. There were no consistent domain differences between the MMSE and MoCA during the third and fourth decades; however, significant differences in memory (P<0.05) and language (P<0.001) emerged in the fifth through ninth decades. Conclusions:We conclude that the MoCA may be a better detector of age-related decrements in cognitive performance than the MMSE, as shown in this community-dwelling adult population.

A comparison of two brief screening measures of cognitive impairment in Huntington's disease.

The goal of this study was to explore whether the Montreal Cognitive Assessment (MoCA), a new screening instrument, would be more sensitive to mild to moderate cognitive impairment in Huntingtons disease (HD) than an established screening measure, the Mini Mental State Exam (MMSE). Our reasoning for this query is that the MoCA includes a broader range of test items and an additional assessment of executive functioning and attention compared with the MMSE. Using the receiver operating characteristic (ROC) analysis to examine performance of HD and control groups on both tests on overall scores and scores from various subdomains (i.e., visuospatial abilities) revealed that the MoCA achieved higher sensitivity without sacrificing specificity in many domains relative to the MMSE.

Basal Ganglia Atrophy in Prodromal Huntington's Disease Is Detectable Over One Year Using Automated Segmentation

Future clinical trials of neuroprotection in prodromal Huntingtons (known as preHD) will require sensitive in vivo imaging biomarkers to track disease progression over the shortest period. Since basal ganglia atrophy is the most prominent structural characteristic of Huntingtons pathology, systematic assessment of longitudinal subcortical atrophy holds great potential for future biomarker development. We studied 36 preHD and 22 age‐matched controls using a novel method to quantify regional change from T1‐weighted structural images acquired 1 year apart. We assessed cross‐sectional volume differences and longitudinal volumetric change in 7 subcortical structures—the accumbens, amygdala, caudate, hippocampus, pallidum, putamen, and thalamus. At baseline, accumbens, caudate, pallidum, and putamen volumes were reduced in preHD versus controls (all P < .01). Longitudinally, atrophy was greater in preHD than controls in the caudate, pallidum, and putamen (all P < .01). Each structure showed a large between‐group effect size, especially the pallidum where Cohens d was 1.21. Using pallidal atrophy as a biomarker, we estimate that a hypothetical 1‐year neuroprotection study would require only 35 preHD per arm to detect a 50% slowing in atrophy and only 138 preHD per arm to detect a 25% slowing in atrophy. The effect sizes calculated for preHD basal ganglia atrophy over 1 year are some of the largest reported to date. Consequently, this translates to strikingly small sample size estimates that will greatly facilitate any future neuroprotection study. This underscores the utility of this automatic image segmentation and longitudinal nonlinear registration method for upcoming studies of preHD and other neurodegenerative disorders.

Impairments in source memory for olfactory and visual stimuli in preclinical and clinical stages of Huntington's disease

Individuals in preclinical and clinical stages of Huntingtons disease (HD) demonstrate impairments in olfactory functioning. In addition, HD patients are impaired in source memory for verbal stimuli. A task combining both source and odor memory may be particularly sensitive to early changes in HD. The present study examined source and item memory for olfactory and visual stimuli in 10 individuals with HD, 10 asymptomatic HD gene carriers, 8 nongene carriers who had a parent with HD, and 20 normal controls. During the study phase, a male and a female experimenter (sources) presented odors and objects to the participant in an alternating sequence. To assess item memory, a stimulus from the study phase (target) and a novel stimulus (distractor) were presented, and the participant was asked to choose the target. To assess source memory, the experimenter presented a stimulus and asked whether the male or female experimenter had previously presented the stimulus. Results indicate that source memory for both visual and olfactory stimuli was impaired in HD patients compared to normal controls. In asymptomatic gene carriers, however, source memory for olfactory stimuli, but not visual stimuli, was more impaired than in nongene carriers and normal controls. Furthermore, gene carriers and HD patients showed a similar degree of impairment in source memory for olfactory stimuli. The only significant impairment found in item memory was for olfactory stimuli in HD patients. These results suggest that source memory for olfactory stimuli may be particularly sensitive to neuropathological changes in preclinical stages of HD.

Automated structural imaging analysis detects premanifest Huntington's disease neurodegeneration within 1 year.

Intense efforts are underway to evaluate neuroimaging measures as biomarkers for neurodegeneration in premanifest Huntingtons disease (preHD). We used a completely automated longitudinal analysis method to compare structural scans in preHD individuals and controls. Using a 1‐year longitudinal design, we analyzed T1‐weighted structural scans in 35 preHD individuals and 22 age‐matched controls. We used the SIENA (Structural Image Evaluation, using Normalization, of Atrophy) software tool to yield overall percentage brain volume change (PBVC) and voxel‐level changes in atrophy. We calculated sample sizes for a hypothetical disease‐modifying (neuroprotection) study. We found significantly greater yearly atrophy in preHD individuals versus controls (mean PBVC controls, −0.149%; preHD, −0.388%; P = .031, Cohens d = .617). For a preHD subgroup closest to disease onset, yearly atrophy was more than 3 times that of controls (mean PBVC close‐to‐onset preHD, −0.510%; P = .019, Cohens d = .920). This atrophy was evident at the voxel level in periventricular regions, consistent with well‐established preHD basal ganglia atrophy. We estimated that a neuroprotection study using SIENA would only need 74 close‐to‐onset individuals in each arm (treatment vs placebo) to detect a 50% slowing in yearly atrophy with 80% power. Automated whole‐brain analysis of structural MRI can reliably detect preHD disease progression in 1 year. These results were attained with a readily available imaging analysis tool, SIENA, which is observer independent, automated, and robust with respect to image quality, slice thickness, and different pulse sequences. This MRI biomarker approach could be used to evaluate neuroprotection in preHD.