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Parkinson Disease: HELP
Articles by Kristy S. Hwang
Based on 5 articles published since 2010
(Why 5 articles?)
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Between 2010 and 2020, Kristy S. Hwang wrote the following 5 articles about Parkinson Disease.
 
+ Citations + Abstracts
1 Article Mapping cortical atrophy in Parkinson's disease patients with dementia. 2013

Hwang, Kristy S / Beyer, Mona K / Green, Amity E / Chung, Christine / Thompson, Paul M / Janvin, Carmen / Larsen, Jan P / Aarsland, Dag / Apostolova, Liana G. ·Department of Neurology, University of California, Los Angeles, CA, USA. ·J Parkinsons Dis · Pubmed #23938313.

ABSTRACT: BACKGROUND: Cognitive impairment is very common in patients with Parkinson's disease (PD). Brain changes accompanying cognitive decline in PD are still not fully established. METHODS: We applied cortical pattern matching and cortical thickness analyses to the three-dimensional T1-weighted brain MRI scans of 14 age-matched cognitively normal elderly (NC), 12 cognitively normal PD (PDC), and 11 PD dementia (PDD) subjects. We used linear regression models to investigate the effect of diagnosis on cortical thickness. All maps were adjusted for multiple comparisons using permutation testing with a threshold p < 0.01. RESULTS: PDD showed significantly thinner bilateral sensorimotor, perisylvian, lateral parietal, as well as right posterior cingulate, parieto-occipital, inferior temporal and lateral frontal cortices relative to NC (left p(corrected) = 0.06, right p(corrected) = 0.009). PDD showed significantly thinner bilateral sensorimotor, right frontal and right parietal-occipital cortices relative to PDC (right p(corrected) = 0.05). The absolute difference in cortical thickness between PDD and the other diagnostic groups ranged from 3% to 19%. CONCLUSION: Our data shows that cognitive decline in PD is associated with cortical atrophy. PDD subjects have the most widespread gray matter atrophy suggesting more cortical involvement as PD patients progress to dementia.

2 Article Cerebrospinal fluid Aβ levels correlate with structural brain changes in Parkinson's disease. 2013

Beyer, Mona K / Alves, Guido / Hwang, Kristy S / Babakchanian, Sona / Bronnick, Kolbjorn S / Chou, Yi-Yu / Dalaker, Turi O / Kurz, Martin W / Larsen, Jan P / Somme, Johanne H / Thompson, Paul M / Tysnes, Ole-Bjørn / Apostolova, Liana G. ·The Norwegian Center for Movement Disorders, Stavanger University Hospital, Stavanger, Norway. mona.beyer@lyse.net ·Mov Disord · Pubmed #23408705.

ABSTRACT: ParkWest is a large Norwegian multicenter study of newly diagnosed drug-naïve subjects with Parkinson's disease (PD). Cognitively normal PD subjects (PDCN) and PD subjects with mild cognitive impairment (PDMCI) from this cohort have significant hippocampal atrophy and ventricular enlargement, compared to normal controls. Here, we aimed to investigate whether the same structural changes are associated with cerebrospinal fluid (CSF) levels of amyloid beta (Aβ)38 , Aβ40 , Aβ42 , total tau (t-tau), and phosphorylated tau (p-tau). We performed three-dimensional radial distance analyses of the hippocampi and lateral ventricles using the MRI data from ParkWest subjects who provided CSF at baseline. Our sample consisted of 73 PDCN and 18 PDMCI subjects. We found significant associations between levels of all three CSF Aβ analytes and t-tau and lateral ventricular enlargement in the pooled sample. In the PDCN sample, all three amyloid analytes showed significant associations with the radial distance of the occipital and frontal horns of the lateral ventricles. CSF Aβ38 and Aβ42 showed negative associations, with enlargement in occipital and frontal horns of the lateral ventricles in the pooled sample, and a negative association with the occipital horns in PDMCI. CSF Aβ levels in early PD correlate with ventricular enlargement, previously associated with PD dementia. Therefore, CSF and MRI markers may help identify PD patients at high risk for developing cognitive decline and dementia in the course of their illness. Contrary to Alzheimer's disease, we found no associations between CSF t-tau and p-tau and hippocampal atrophy.

3 Article Verbal memory is associated with structural hippocampal changes in newly diagnosed Parkinson's disease. 2013

Beyer, Mona K / Bronnick, Kolbjorn S / Hwang, Kristy S / Bergsland, Niels / Tysnes, Ole Bjorn / Larsen, Jan Petter / Thompson, Paul M / Somme, Johanne H / Apostolova, Liana G. ·Norwegian Centre for Movement Disorders, Stavanger University Hospital, Stavanger, Norway. monbey@ous-hf.no ·J Neurol Neurosurg Psychiatry · Pubmed #23154124.

ABSTRACT: BACKGROUND AND OBJECTIVE: Cognitive impairment, including impairment of episodic memory, is frequently found in newly diagnosed Parkinson's disease (PD). In this longitudinal observational study we investigated whether performance in memory encoding, retention, recognition and free recall is associated with reduced hippocampal radial distance. METHODS: We analysed baseline T1-weighted brain MRI data from 114 PD subjects without cognitive impairment, 29 PD subjects with mild cognitive impairment and 99 normal controls from the ParkWest study. Age- and education-predicted scores for the California Verbal Learning Test 2 (CVLT-2) and tests of executive function were regressed against hippocampal radial distance while adjusting for imaging centre. RESULTS: There was no association between encoding or performance on executive tests and hippocampal atrophy in the PD group. In the full PD sample we found bilaterally significant associations between lower delayed free recall scores and hippocampal atrophy in the CA1, CA3 and subiculum area (left, p=0.0013; right, p=0.0082). CVLT-2 short delay free recall scores were associated with bilateral hippocampal CA1 and subicular atrophy in the full PD sample (left, p=0.013; right, p=0.047). CVLT-2 recognition scores showed a significant association with right-sided subicular and CA1 atrophy in the full PD sample (p=0.043). CONCLUSIONS: At the time of PD diagnosis, subjects' verbal memory performance in recall and recognition are associated with atrophy of the hippocampus, while encoding is not associated with hippocampal radial distance. We postulate that impaired recall and recognition might reflect deficient memory consolidation at least partly due to structural hippocampal changes.

4 Article Hippocampal and ventricular changes in Parkinson's disease mild cognitive impairment. 2012

Apostolova, Liana / Alves, Guido / Hwang, Kristy S / Babakchanian, Sona / Bronnick, Kolbjorn S / Larsen, Jan Petter / Thompson, Paul M / Chou, Yi-Yu / Tysnes, Ole B / Vefring, Hege K / Beyer, Mona K. ·Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA. lapostolova@mednet.ucla.edu ·Neurobiol Aging · Pubmed #21813212.

ABSTRACT: We analyzed T1-weighted brain magnetic resonance imaging data of 100 cognitively normal elderly controls (NC), 127 cognitively normal Parkinson's disease (PD; PDCN) and 31 PD-associated mild cognitive impairment (PDMCI) subjects from the Norwegian ParkWest study. Using automated segmentation methods, followed by the radial distance technique and multiple linear regression we studied the effect of clinical diagnosis on hippocampal and ventricular radial distance while adjusting for age, education, and scanning site. PDCN subjects had significantly smaller bilateral hippocampal radial distance relative to NC. Nonamnestic PDMCI subjects showed smaller right hippocampal radial distance relative to NC. PDMCI subjects showed significant enlargement of all portions of the lateral ventricles relative to NC and significantly larger bilateral temporal and occipital and left frontal lateral ventricular expansion relative to PDCN subjects. Nonamnestic PDMCI subjects showed significant ventricular enlargement spanning all parts of the lateral ventricle while those with amnestic PDMCI showed changes localized to the left occipital horn. Hippocampal atrophy and lateral ventricular enlargement show promise as structural biomarkers for PD.

5 Article Hippocampal, caudate, and ventricular changes in Parkinson's disease with and without dementia. 2010

Apostolova, Liana G / Beyer, Mona / Green, Amity E / Hwang, Kristy S / Morra, Jonathan H / Chou, Yi-Yu / Avedissian, Christina / Aarsland, Dag / Janvin, Carmen C / Larsen, Jan P / Cummings, Jeffrey L / Thompson, Paul M. ·Department of Neurology, David Geffen School of Medicine, UCLA, California, USA. lapostolova@mednet.ucla.edu ·Mov Disord · Pubmed #20437538.

ABSTRACT: Parkinson's disease (PD) has been associated with mild cognitive impairment (PDMCI) and with dementia (PDD). Using radial distance mapping, we studied the 3D structural and volumetric differences between the hippocampi, caudates, and lateral ventricles in 20 cognitively normal elderly (NC), 12 cognitively normal PD (PDND), 8 PDMCI, and 15 PDD subjects and examined the associations between these structures and Unified Parkinson's Disease Rating Scale (UPDRS) Part III:motor subscale and Mini-Mental State Examination (MMSE) performance. There were no hippocampal differences between the groups. 3D caudate statistical maps demonstrated significant left medial and lateral and right medial atrophy in the PDD vs. NC, and right medial and lateral caudate atrophy in PDD vs. PDND. PDMCI showed trend-level significant left lateral caudate atrophy vs. NC. Both left and right ventricles were significantly larger in PDD relative to the NC and PDND with posterior (body/occipital horn) predominance. The magnitude of regionally significant between-group differences in radial distance ranged between 20-30% for caudate and 5-20% for ventricles. UPDRS Part III:motor subscale score correlated with ventricular enlargement. MMSE showed significant correlation with expansion of the posterior lateral ventricles and trend-level significant correlation with caudate head atrophy. Cognitive decline in PD is associated with anterior caudate atrophy and ventricular enlargement.