Publications by authors named "Kyoo H Cho"

6 Publications

  • Page 1 of 1

Unsupervised machine learning reveals lesional variability in focal cortical dysplasia at mesoscopic scale.

Neuroimage Clin 2020 18;28:102438. Epub 2020 Sep 18.

Neuroimaging of Epilepsy Laboratory, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada. Electronic address:

Objective: Focal cortical dysplasia (FCD) is the most common epileptogenic developmental malformation and a prevalent cause of surgically amenable epilepsy. While cellular and molecular biology data suggest that FCD lesional characteristics lie along a spectrum, this notion remains to be verified in vivo. We tested the hypothesis that machine learning applied to MRI captures FCD lesional variability at a mesoscopic scale.

Methods: We studied 46 patients with histologically verified FCD Type II and 35 age- and sex-matched healthy controls. We applied consensus clustering, an unsupervised learning technique that identifies stable clusters based on bootstrap-aggregation, to 3 T multicontrast MRI (T1-weighted MRI and FLAIR) features of FCD normalized with respect to distributions in controls.

Results: Lesions were parcellated into four classes with distinct structural profiles variably expressed within and across patients: Class-1 with isolated white matter (WM) damage; Class-2 combining grey matter (GM) and WM alterations; Class-3 with isolated GM damage; Class-4 with GM-WM interface anomalies. Class membership was replicated in two independent datasets. Classes with GM anomalies impacted local function (resting-state fMRI derived ALFF), while those with abnormal WM affected large-scale connectivity (assessed by degree centrality). Overall, MRI classes reflected typical histopathological FCD characteristics: Class-1 was associated with severe WM gliosis and interface blurring, Class-2 with severe GM dyslamination and moderate WM gliosis, Class-3 with moderate GM gliosis, Class-4 with mild interface blurring. A detection algorithm trained on class-informed data outperformed a class-naïve paradigm.

Significance: Machine learning applied to widely available MRI contrasts uncovers FCD Type II variability at a mesoscopic scale and identifies tissue classes with distinct structural dimensions, functional and histopathological profiles. Integrating in vivo staging of FCD traits with automated lesion detection is likely to inform the development of novel personalized treatments.
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http://dx.doi.org/10.1016/j.nicl.2020.102438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7520429PMC
September 2020

Olfactory performance acts as a cognitive reserve in non-demented patients with Parkinson's disease.

Parkinsonism Relat Disord 2014 Feb 4;20(2):186-91. Epub 2013 Nov 4.

Department of Neurology and Brain Research Institute, Yonsei University College of Medicine, Seoul, South Korea; Severance Biomedical Science Institute, Seoul, South Korea. Electronic address:

Objective: To explore whether olfactory performance acts as a cognitive reserve in non-demented patients with Parkinson's disease (PD).

Methods: Patients with non-demented PD (n = 119) underwent T1-weighted MRI and olfactory identification tests. According to their olfactory performance, PD patients were subdivided into three groups of high score (PD-H, n = 38), middle score (PD-M, n = 48), and low score (PD-L, n = 33). We investigated the pattern of gray matter (GM) density according to olfactory performance using voxel-based morphometry (VBM) and analyzed the correlation between GM density and olfactory performance.

Results: No significant differences in demographic characteristics were observed among the groups. A neuropsychological test showed that cognitive deficits in verbal memory function were more severe in the PD-L group than in the PD-H group. However, a VBM analysis revealed that patients in the PD-H group possessed significantly decreased GM density in the bilateral temporal areas, orbitofrontal areas, mesiofrontal areas extending into the cingulate gyrus, and prefrontal areas, compared with patients in the PD-L group. No areas exhibiting a significant difference in GM density were observed between the PD-H and PD-M groups. Olfactory performance in patients with PD was negatively correlated with both the brain GM volume and intracerebral volume; in particular, GM density in the caudate nucleus and putamen exhibited a negative correlation with olfactory performance.

Conclusions: Our data show that a high olfactory performance may compensate GM volume loss in order to minimize the exhibition of cognitive impairment and thus may act as a cognitive reserve in non-demented patients with PD.
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http://dx.doi.org/10.1016/j.parkreldis.2013.10.024DOI Listing
February 2014

Thalamic volume and related visual recognition are associated with freezing of gait in non-demented patients with Parkinson's disease.

Parkinsonism Relat Disord 2013 Dec 9;19(12):1106-9. Epub 2013 Aug 9.

Department of Neurology, Yonsei University College of Medicine, Seoul, South Korea.

Background: The pathophysiology of freezing of gait (FOG) in non-demented Parkinson's disease (PD) patients remains poorly understood. Recent studies have suggested that neurochemical alterations in the cholinergic systems play a role in the development of FOG. Here, we evaluated the association between subcortical cholinergic structures and FOG in patients with non-demented PD.

Methods: We recruited 46 non-demented patients with PD, categorized into PD with (n = 16) and without FOG (n = 30) groups. We performed neuropsychological test, region-of-interest-based volumetric analysis of the substantia innominata (SI) and automatic analysis of subcortical brain structures using a computerized segmentation procedure.

Results: The comprehensive neuropsychological assessment showed that PD patients with FOG had lower cognitive performance in the frontal executive and visual-related functions compared with those without freezing of gait. The normalized SI volume did not differ significantly between the two groups (1.65 ± 0.18 vs. 1.68 ± 0.31). The automatic analysis of subcortical structures revealed that the thalamic volumes were significantly reduced in PD patients with FOG compared with those without FOG after adjusting for age, sex, disease duration, the Unified PD Rating Scale scores and total intracranial volume (left: 6.71 vs. 7.16 cm3, p = 0.029, right: 6.47 vs. 6.91 cm3, p = 0.026). Multiple linear regression analysis revealed that thalamic volume showed significant positive correlations with visual recognition memory (left: β = 0.441, p = 0.037, right: β = 0.498, p = 0.04).

Conclusions: These data suggest that thalamic volume and related visual recognition, rather than the cortical cholinergic system arising from the SI, may be a major contributor to the development of freezing of gait in non-demented patients with PD.
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http://dx.doi.org/10.1016/j.parkreldis.2013.07.023DOI Listing
December 2013

Exploratory analysis of neuropsychological and neuroanatomical correlates of progressive mild cognitive impairment in Parkinson's disease.

J Neurol Neurosurg Psychiatry 2014 Jan 4;85(1):7-16. Epub 2013 Jul 4.

Department of Neurology and Brain Research Institute, Yonsei University College of Medicine, , Seoul, Korea.

Background: Parkinson's disease with mild cognitive impairment (PD-MCI) is a heterogeneous entity in terms of cognitive profiles and conversion to dementia. However, the risk factors for ongoing cognitive decline in patients with PD-MCI are not clearly defined.

Methods: 51 patients with PD-MCI were prospectively followed-up for a minimum of 2 years. Subjects were classified as MCI converters (n=15) or MCI non-converters (n=36) based on whether they were subsequently diagnosed with PD dementia. We explored cognitive profiles and neuroanatomical characteristics of PD-MCI converters using voxel based morphometry (VBM) of grey matter (GM) density and region of interest based volumetric analysis of the substantia innominata (SI).

Results: PD-MCI converters showed more severe cognitive deficits in frontal executive functions, immediate verbal memory and visual recognition memory compared with PD-MCI non-converters. VBM analysis revealed that PD-MCI converters had significantly lower GM density in the left prefrontal areas, left insular cortex and bilateral caudate nucleus compared with that in PD-MCI non-converters. The mean normalised SI volume was significantly smaller in both PD-MCI converters (1.19±0.35, p<0.001) and PD-MCI non-converters (1.52±0.27, p<0.001) compared with that in controls (1.87±0.19). PD-MCI converters had a significantly smaller normalised SI volume than PD-MCI non-converters (p<0.001).

Conclusions: Our data show that atrophy in the frontostriatal areas and cholinergic structures, as well as frontal lobe associated cognitive performance, may act as predictors of dementia in PD-MCI patients, suggesting distinctive patterns of cognitive profiles and a neuroanatomical basis for progressive PD-MCI.
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http://dx.doi.org/10.1136/jnnp-2013-305062DOI Listing
January 2014

The pattern of cortical atrophy in Parkinson's disease with mild cognitive impairment according to the timing of cognitive dysfunction.

J Neurol 2012 Mar 5;259(3):469-73. Epub 2011 Aug 5.

Department of Neurology and Brain Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul, 120-752, South Korea.

The density of Lewy bodies or the concurrent β-amyloid pathology would act as modulators in the relative timing of dementia during the course of Parkinson's disease. Depending on the temporal relationship between the onset of parkinsonism and that of cognitive impairment, patients with Parkinson's disease with mild cognitive impairment were divided into two groups of earlier (<1 year) and later (≥1 year) cognitive decline, and cortical atrophy patterns and correlation of gray matter and timing of cognitive decline were analyzed using voxel-based morphometry. The morphometric analysis showed that patients with earlier cognitive decline demonstrated greater cortical atrophy in the inferior parietal and orbitofrontal areas than did those with later cognitive decline. Additionally, the anatomical bases of the timing of their cognitive decline differed in terms of correlation patterns. These data suggest that the pathological burden in Parkinson's disease with mild cognitive impairment may be more severe in patients with earlier cognitive decline than in those with later cognitive decline, and that the neural basis corresponding to the timing of cognitive decline may differ in these patients.
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http://dx.doi.org/10.1007/s00415-011-6203-xDOI Listing
March 2012

Chorea induced by antihistamine drugs.

Mov Disord 2010 Mar;25(4):519-20

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http://dx.doi.org/10.1002/mds.22965DOI Listing
March 2010