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10 "Young H. Sohn"
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Review Article
Emerging Concepts of Motor Reserve in Parkinson’s Disease
Seok Jong Chung, Jae Jung Lee, Phil Hyu Lee, Young H. Sohn
J Mov Disord. 2020;13(3):171-184.   Published online August 31, 2020
DOI: https://doi.org/10.14802/jmd.20029
  • 6,441 View
  • 254 Download
  • 10 Citations
AbstractAbstract PDF
The concept of cognitive reserve (CR) in Alzheimer’s disease (AD) explains the differences between individuals in their susceptibility to AD-related pathologies. An enhanced CR may lead to less cognitive deficits despite severe pathological lesions. Parkinson’s disease (PD) is also a common neurodegenerative disease and is mainly characterized by motor dysfunction related to striatal dopaminergic depletion. The degree of motor deficits in PD is closely correlated to the degree of dopamine depletion; however, significant individual variations still exist. Therefore, we hypothesized that the presence of motor reserve (MR) in PD explains the individual differences in motor deficits despite similar levels of striatal dopamine depletion. Since 2015, we have performed a series of studies investigating MR in de novo patients with PD using the data of initial clinical presentation and dopamine transporter PET scan. In this review, we summarized the results of these published studies. In particular, some premorbid experiences (i.e., physical activity and education) and modifiable factors (i.e., body mass index and white matter hyperintensity on brain image studies) could modulate an individual’s capacity to tolerate PD pathology, which can be maintained throughout disease progression.
Original Article
Association between Olfactory Deficit and Motor and Cognitive Function in Parkinson’s Disease
Han Soo Yoo, Seok Jong Chung, Yang Hyun Lee, Byoung Seok Ye, Young H. Sohn, Phil Hyu Lee
J Mov Disord. 2020;13(2):133-141.   Published online April 6, 2020
DOI: https://doi.org/10.14802/jmd.19082
  • 5,963 View
  • 234 Download
  • 11 Citations
AbstractAbstract PDFSupplementary Material
Objective
To investigate whether baseline olfactory dysfunction in Parkinson’s disease (PD) patients is associated with baseline and longitudinal motor and cognitive function.
Methods
We recruited 228 drug-naïve PD patients who were followed for a mean of 6 years. Patients underwent the Cross-Cultural Smell Identification Test (CCSIT), a neuropsychological test, and N-(3-[18F]fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane positron emission tomography within 6 months of the baseline evaluation. Olfactory dysfunction was categorized as normosmia (CCSIT score ≥ 9), hyposmia (CCSIT score 5–8), and anosmia (CCSIT score ≤ 4). During the follow-up period, we investigated changes in the levodopa-equivalent dose (LED) and the occurrence of wearing-off, levodopa-induced dyskinesia, and dementia.
Results
Among the PD patients, 80.7% were hyposmic at the time of diagnosis, and 26.1% were anosmic. Baseline olfactory dysfunction was not associated with either initial parkinsonian motor symptoms or with the longitudinal LED increment and motor complications. Meanwhile, the anosmic group had lower baseline scores on the Korea version of the Boston Naming Test and Stroop color reading test than the normosmic and hyposmic groups. The anosmic group exhibited a higher rate of conversion to dementia than the normosmic [adjusted hazard ratio (HR) 3.99, 95% confidence interval (CI) 1.08–14.72] and hyposmic (adjusted HR 2.48, 95% CI 1.15–5.32) PD groups, regardless of baseline motor deficits and cognitive status.
Conclusion
Baseline olfactory dysfunction was not associated with motor deficits and complications, but it was associated with cognitive dysfunction and prognosis, suggesting that severe olfactory impairment may reflect early cortical involvement, probably in the frontotemporal region, and rapid spreading of Lewy body pathology.
Case Report
A Case of Abnormal Postures in the Left Extremities after Pontine Hemorrhage: Dystonia or Pseudodystonia?
Chan Wook Park, Seok Jong Chung, Young H. Sohn, Phil Hyu Lee
J Mov Disord. 2020;13(1):62-65.   Published online January 31, 2020
DOI: https://doi.org/10.14802/jmd.19074
  • 3,366 View
  • 115 Download
  • 1 Citations
AbstractAbstract PDFSupplementary Material
It is difficult to determine the pathoanatomical correlates of dystonia because of its complex pathophysiology, and most cases with secondary dystonia are associated with basal ganglia lesions. Moreover, it is a challenging issue that patients with abnormal postures accompanied by other neurological findings in the affected body part (e.g., sensory loss) can be diagnosed with true dystonia or pseudodystonia. Here, we report a case of abnormal postures with loss of proprioception in the left extremities after right dorsal pontine hemorrhage.
Original Article
Heterogeneous Patterns of Striatal Dopamine Loss in Patients with Young- versus Old-Onset Parkinson’s Disease: Impact on Clinical Features
Seok Jong Chung, Han Soo Yoo, Yang Hyun Lee, Phil Hyu Lee, Young H. Sohn
J Mov Disord. 2019;12(2):113-119.   Published online May 30, 2019
DOI: https://doi.org/10.14802/jmd.18064
  • 5,120 View
  • 128 Download
  • 13 Citations
AbstractAbstract PDFSupplementary Material
Objective
Ample evidence has suggested that age at onset of Parkinson’s disease (PD) is associated with heterogeneous clinical features in individuals. We hypothesized that this may be attributed to different patterns of nigrostriatal dopamine loss.
Methods
A total of 205 consecutive patients with de novo PD who underwent 18F-FP-CIT PET scans (mean follow-up duration, 6.31 years) were divided into three tertile groups according to their age at onset of parkinsonian motor symptoms. Striatal dopamine transporter (DAT) availability was compared between the old- (n = 73) and young-onset (n = 66) groups. In addition, the risk of developing freezing of gait (FOG) and longitudinal requirements for dopaminergic medications were examined.
Results
The old-onset PD group (mean age at onset, 72.66 years) exhibited more severe parkinsonian motor signs than the young-onset group (52.58 years), despite comparable DAT availability in the posterior putamen; moreover, the old-onset group exhibited more severely decreased DAT availability in the caudate than the young-onset group. A Cox regression model revealed that the old-onset PD group had a higher risk for developing FOG than the young-onset group [hazard ratio 2.523, 95% confidence interval (1.239–5.140)]. The old-onset group required higher doses of dopaminergic medications for symptom control than the young-onset group over time.
Conclusion
The present study demonstrated that the old-onset PD group exhibited more severe dopamine loss in the caudate and were more likely to develop gait freezing, suggesting that age at onset may be one of the major determinants of the pattern of striatal dopamine depletion and progression of gait disturbance in PD.
Case Report
Familial Hyperekplexia, a Potential Cause of Cautious Gait: A New Korean Case and a Systematic Review of Phenotypes
Yoonju Lee, Nan Young Kim, Sangkyoon Hong, Su Jin Chung, Seong Ho Jeong, Phil Hyu Lee, Young H. Sohn
J Mov Disord. 2017;10(1):53-58.   Published online December 27, 2016
DOI: https://doi.org/10.14802/jmd.16044
  • 8,439 View
  • 168 Download
  • 10 Citations
AbstractAbstract PDFSupplementary Material
Familial hyperekplexia, also called startle disease, is a rare neurological disorder characterized by excessive startle responses to noise or touch. It can be associated with serious injury from frequent falls, apnea spells, and aspiration pneumonia. Familial hyperekplexia has a heterogeneous genetic background with several identified causative genes; it demonstrates both dominant and recessive inheritance in the α1 subunit of the glycine receptor (GLRA1), the β subunit of the glycine receptor and the presynaptic sodium and chloride-dependent glycine transporter 2 genes. Clonazepam is an effective medical treatment for hyperekplexia. Here, we report genetically confirmed familial hyperekplexia patients presenting early adult cautious gait. Additionally, we review clinical features, mode of inheritance, ethnicity and the types and locations of mutations of previously reported hyperekplexia cases with a GLRA1 gene mutation.
Original Articles
The MMSE and MoCA for Screening Cognitive Impairment in Less Educated Patients with Parkinson’s Disease
Ji In Kim, Mun Kyung Sunwoo, Young H. Sohn, Phil Hyu Lee, Jin Y. Hong
J Mov Disord. 2016;9(3):152-159.   Published online September 21, 2016
DOI: https://doi.org/10.14802/jmd.16020
  • 16,401 View
  • 353 Download
  • 27 Citations
AbstractAbstract PDF
Objective
To explore whether the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) can be used to screen for dementia or mild cognitive impairment (MCI) in less educated patients with Parkinson’s disease (PD).
Methods
We reviewed the medical records of PD patients who had taken the Korean MMSE (K-MMSE), Korean MoCA (K-MoCA), and comprehensive neuropsychological tests. Predictive values of the K-MMSE and K-MoCA for dementia or MCI were analyzed in groups divided by educational level.
Results
The discriminative powers of the K-MMSE and K-MoCA were excellent [area under the curve (AUC) 0.86–0.97] for detecting dementia but not for detecting MCI (AUC 0.64–0.85). The optimal screening cutoff values of both tests increased with educational level for dementia (K-MMSE < 15 for illiterate, < 20 for 0.5–3 years of education, < 23 for 4–6 years, < 25 for 7–9 years, and < 26 for 10 years or more; K-MoCA < 7 for illiterate, < 13 for 0.5–3 years, < 16 for 4–6 years, < 19 for 7–9 years, < 20 for 10 years or more) and MCI (K-MMSE < 19 for illiterate, < 26 for 0.5–3 years, < 27 for 4–6 years, < 28 for 7–9 years, and < 29 for 10 years or more; K-MoCA < 13 for illiterate, < 21 for 0.5–3 years, < 23 for 4–6 years, < 25 for 7–9 years, < 26 for 10 years or more).
Conclusion
Both MMSE and MoCA can be used to screen for dementia in patients with PD, regardless of educational level; however, neither test is sufficient to discriminate MCI from normal cognition without additional information.
Clinical Heterogeneity of Atypical Pantothenate Kinase-Associated Neurodegeneration in Koreans
Jae-Hyeok Lee, Jongkyu Park, Ho-Sung Ryu, Hyeyoung Park, Young Eun Kim, Jin Yong Hong, Sang Ook Nam, Young-Hee Sung, Seung-Hwan Lee, Jee-Young Lee, Myung Jun Lee, Tae-Hyoung Kim, Chul Hyoung Lyoo, Sun Ju Chung, Seong Beom Koh, Phil Hyu Lee, Jin Whan Cho, Mee Young Park, Yun Joong Kim, Young H. Sohn, Beom Seok Jeon, Myung Sik Lee
J Mov Disord. 2016;9(1):20-27.   Published online January 25, 2016
DOI: https://doi.org/10.14802/jmd.15058
  • 18,412 View
  • 210 Download
  • 13 Citations
AbstractAbstract PDFSupplementary Material
Objective
Neurodegeneration with brain iron accumulation (NBIA) represents a group of inherited movement disorders characterized by iron accumulation in the basal ganglia. Recent advances have included the identification of new causative genes and highlighted the wide phenotypic variation between and within the specific NBIA subtypes. This study aimed to investigate the current status of NBIA in Korea.
Methods
We collected genetically confirmed NBIA patients from twelve nationwide referral hospitals and from a review of the literature. We conducted a study to describe the phenotypic and genotypic characteristics of Korean adults with atypical pantothenate kinase-associated neurodegeneration (PKAN).
Results
Four subtypes of NBIA including PKAN (n = 30), PLA2G6-related neurodegeneration (n = 2), beta-propeller protein-associated neurodegeneration (n = 1), and aceruloplasminemia (n = 1) have been identified in the Korean population. The clinical features of fifteen adults with atypical PKAN included early focal limb dystonia, parkinsonism-predominant feature, oromandibular dystonia, and isolated freezing of gait (FOG). Patients with a higher age of onset tended to present with parkinsonism and FOG. The p.R440P and p.D378G mutations are two major mutations that represent approximately 50% of the mutated alleles. Although there were no specific genotype-phenotype correlations, most patients carrying the p.D378G mutation had a late-onset, atypical form of PKAN.
Conclusions
We found considerable phenotypic heterogeneity in Korean adults with atypical PKAN. The age of onset may influence the presentation of extrapyramidal symptoms.
Gender Differences in Age-Related Striatal Dopamine Depletion in Parkinson’s Disease
Jae Jung Lee, Jee Hyun Ham, Phil Hyu Lee, Young H. Sohn
J Mov Disord. 2015;8(3):130-135.   Published online September 10, 2015
DOI: https://doi.org/10.14802/jmd.15031
  • 20,527 View
  • 106 Download
  • 22 Citations
AbstractAbstract PDFSupplementary Material
Objective Gender differences are a well-known clinical characteristic of Parkinson’s disease (PD). In-vivo imaging studies demonstrated that women have greater striatal dopamine transporter (DAT) activity than do men, both in the normal population and in PD patients. We hypothesize that women exhibit more rapid aging-related striatal DAT reduction than do men, as the potential neuroprotective effect of estrogen wanes with age.
Methods This study included 307 de novo PD patients (152 men and 155 women) who underwent DAT scans for an initial diagnostic work-up. Gender differences in age-related DAT decline were assessed in striatal sub-regions using linear regression analysis.
Results Female patients exhibited greater DAT activity compared with male patients in all striatal sub-regions. The linear regression analysis revealed that age-related DAT decline was greater in the anterior and posterior caudate, and the anterior putamen in women compared with men; we did not observe this difference in other sub-regions.
Conclusions This study demonstrated the presence of gender differences in age-related DAT decline in striatal sub-regions, particularly in the antero-dorsal striatum, in patients with PD, presumably due to aging-related decrease in estrogen. Because this difference was not observed in the sensorimotor striatum, this finding also suggests that women may not have a greater capacity to tolerate PD pathogenesis than do men.
Apathy and Olfactory Dysfunction in Early Parkinson’s Disease
Jin Yong Hong, Mun Kyung Sunwoo, Jee Hyun Ham, Jae Jung Lee, Phil Hyu Lee, Young H. Sohn
J Mov Disord. 2015;8(1):21-25.   Published online January 31, 2015
DOI: https://doi.org/10.14802/jmd.14029
  • 13,314 View
  • 92 Download
  • 20 Citations
AbstractAbstract PDF
Objective Olfactory and emotional dysfunctions are very common in patients with Parkinson’s disease (PD). Olfaction and emotions share common neuroanatomical substrates. Therefore, in this study, we evaluated the association between olfactory and emotional dysfunctions in patients with PD.
Methods Parkinson’s disease patients who had been assessed for their olfactory function and neuropsychiatric symptoms including emotional dysfunction were included. A logistic regression analysis was performed to evaluate the association between low olfaction and different neuropsychiatric symptoms.
Results The patients with low olfaction (cross cultural smell identification test score ≤ 6) showed a higher prevalence of apathy when compared with those with high olfaction, whereas the frequencies of other neuropsychiatric symptoms were comparable between the two groups. A multivariate logistic regression analysis revealed that the presence of apathy/indifference [odds ratio (OR) = 2.859, p = 0.007], age 70 years or more (OR = 2.281, p = 0.009), and the male gender (OR = 1.916, p = 0.030) were significantly associated with low olfaction.
Conclusions Our results demonstrate that apathy/indifference is a unique emotional dysfunction associated with olfactory dysfunction in PD. The findings also suggest that PD patients with low olfaction have a high prevalence of apathy.
Case Report
Chorea as an Initial Manifestation of Polycythemia Vera
Ji Eun Lee, Hae-Won Shin, Young H. Sohn
J Mov Disord. 2008;1(2):82-85.
DOI: https://doi.org/10.14802/jmd.08015
  • 9,689 View
  • 122 Download
AbstractAbstract PDF

Chorea is a rare complication of polycythemia vera (PV). We report a 58-year-old woman with acute onset chorea without structural lesion in the basal ganglia. The physical and laboratory findings were compatible with the diagnosis of PV. After repeated phlebotomies her chorea was improved. PV should be considered as one of the possible etiologies of chorea, as early diagnosis is important to lead to the effective treatment and prevention of complications.


JMD : Journal of Movement Disorders