Publications by authors named "Yu Mi Hwang"

6 Publications

  • Page 1 of 1

Clinical Factors Associated with Balance Function in the Early Subacute Phase after Stroke.

Am J Phys Med Rehabil 2021 Jul 27. Epub 2021 Jul 27.

Department of Physical Medicine and Rehabilitation, Korea University College of Medicine, Seoul, Republic of Korea Brain Convergence Research Center, Korea University, Seoul, Republic of Korea Department of Biomedical Sciences, Korea University, Seoul, Republic of Korea.

Objective: To investigate the key factors of balance function in the early subacute phase after stroke.

Design: Ninety-four stroke patients were included. Multiple variables were evaluated, including demographic factors, clinical variables (stroke type; lesion site; Korean Mini-Mental State Examination [MMSE]; motor strength of the hip, knee, and ankle joints; Fugl-Meyer Assessment of lower extremity [FMA-LE]); neurophysiologic variables (amplitude ratio of somatosensory evoked potential [SEP] of the tibial nerves), and laterality index of fractional anisotropy (FA-LI) of the corticospinal tract using diffusion tensor imaging. Balance function was measured using the Berg balance scale (BBS).

Results: The BBS score was significantly negatively correlated with age and FA-LI and positively correlated with MMSE; FMA-LE; motor strength of the affected hip, knee, and ankle joint; and SEP amplitude ratio (p < 0.05). The abnormal SEP group and poor integrity of the corticospinal tract group showed significantly decreased BBS scores. In multivariable logistic regression analysis, age, FMA-LE score, and ankle plantar flexion strength were significantly associated with balance function (odds ratios: 0.919, 1.181, and 15.244, respectively, p < 0.05).

Conclusion: Higher age, severe initial motor impairment, and strength of the affected lower extremity muscles, especially the ankle plantar flexor, are strongly associated with poor balance function early after stroke.
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July 2021

Development of a categorical naming test in Korean: Standardization and clinical application for patients with stroke.

PLoS One 2021 19;16(2):e0247118. Epub 2021 Feb 19.

Brain Convergence Research Center, Korea University College of Medicine, Seoul, Republic of Korea.

Purpose: The purpose of this study was to develop and standardize a new categorical naming test, titled the Categorical Naming Test (CNT), for stroke patients, and to investigate its validity and clinical usefulness for patients with stroke.

Materials And Methods: The CNT was developed based on semantic category, imageability, and psycholinguistic factors such as word frequency and word length. The test materials included two main semantic categories (living objects and artificial objects) comprising 60 items. We standardized the CNT on 221 healthy adults and administered the CNT to 112 stroke patients.

Results: Internal consistency and concurrent validity of the test were high. The mean total CNT scores varied significantly according to participants' age, sex, and education. Among healthy controls, the scores for naming living objects were significantly higher than those for artificial objects. The analysis of stroke patients showed that the total CNT score revealed a statistically significant difference based on the patients' lesion laterality and presence of aphasia, after controlling for age, sex, and education. However, the categorical scores achieved by comparing the naming scores for living and artificial objects showed no significant differences according to lesion laterality, stroke type, and presence of aphasia.

Conclusion: The CNT is a newly developed version of an overt naming task with high internal consistency validity for stroke patients in Korea. The newly developed CNT can prove useful in evaluating naming ability in stroke patients.
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August 2021

Reliability and Validity of the Comprehensive Limb and Oral Apraxia Test: Standardization and Clinical Application in Korean Patients With Stroke.

Ann Rehabil Med 2019 Oct 31;43(5):544-554. Epub 2019 Oct 31.

Department of Speech Pathology, Daegu University, Gyeongsan, Korea.

Objective: To develop and standardize the Limb and Oral Apraxia Test (LOAT) for Korean patients and investigate its reliability, validity, and clinical usefulness for patients with stroke.

Methods: We developed the LOAT according to a cognitive neuropsychological model of limb and oral praxis. The test included meaningless, intransitive, transitive, and oral praxis composed of 72 items (56 items on limb praxis and 16 items on oral praxis; maximum score 216). We standardized the LOAT in a nationwide sample of 324 healthy adults. Intra-rater and inter-rater reliability and concurrent validity tests were performed in patients with stroke. We prospectively applied the LOAT in 80 patients and analyzed the incidence of apraxia. We also compared the clinical characteristics between the apraxia and non-apraxia groups.

Results: The internal consistency was high (Cronbach's alpha=0.952). The inter-rater and intra-rater reliability and concurrent validity were also high (r=0.924-0.992, 0.961-0.999, and 0.830, respectively; p<0.001). The mean total, limb, and oral scores were not significantly different according to age and education (p>0.05). Among the 80 patients with stroke, 19 (23.8%) had limb apraxia and 21 (26.3%) had oral apraxia. Left hemispheric lesions and aphasia were significantly more frequently observed in the limb/oral apraxia group than in the non-apraxia group (p<0.001).

Conclusion: The LOAT is a newly developed comprehensive test for limb and oral apraxia for Korean patients with stroke. It has high internal consistency, reliability, and validity and is a useful apraxia test for patients with stroke.
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October 2019

Increased Brainstem Serotonergic Transporter Availability in Adult Migraineurs: an [(18)F]FP-CIT PET Imaging Pilot Study.

Nucl Med Mol Imaging 2016 Mar 5;50(1):70-5. Epub 2015 Oct 5.

Department of Neurology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 110-799 Republic of Korea.

Purpose: Recent studies have proposed central serotonergic dysfunction as a major pathophysiology of migraine. We investigated serotonin transporter (SERT) availability in migraineurs using F-18-N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-iodophenyl) nortropane ([(18)F]FP-CIT) positron emission tomography (PET).

Methods: Brain [(18)F]FP-CIT PET images were obtained in eight women with migraine during headache free phase and 12 healthy adult women, 120 min after injection of 185 MBq. Non-displaceable binding potential (BP ND) of [(18)F]FP-CIT, which is an estimate of SERT availability, was calculated at the brainstem and compared with clinical parameters.

Results: BP ND at the brainstem was significantly higher in adult migraineurs (n = 6, 1.15 ± 0.17) than healthy subjects (0.95 ± 0.14) (p = 0.04). Healthy subjects demonstrated negative correlation between brainstem BP ND and age (r = -0.64, p = 0.02), whereas this age-related decline pattern was not found in the migraineurs. Severity of migraine attack was significantly correlated with brainstem BP ND (r = 0.66, p = 0.02), when age and duration of illness were corrected.

Conclusions: Increased SERT availability in the brainstem of adult migraineurs indicates low serotonin neurotransmission during headache-free phase. Patients who experience more painful headaches have lower serotonin neurotransmission. [(18)F]FP-CIT PET is a useful in vivo imaging technique for evaluating brainstem SERT availability in migraineurs.
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March 2016

Differential Diagnosis of Patients with Inconclusive Parkinsonian Features Using [(18)F]FP-CIT PET/CT.

Nucl Med Mol Imaging 2014 Jun 11;48(2):106-13. Epub 2013 Dec 11.

Department of Neurology, Korea University College of Medicine, 126-1, Anam-dong 5-ga, Seongbuk-gu, Seoul, 136-705 Republic of Korea.

Purpose: It is often difficult to differentiate parkinsonism, especially when patients show uncertain parkinsonian features. We investigated the usefulness of dopamine transporter (DAT) imaging for the differential diagnosis of inconclusive parkinsonism using [(18)F]FP-CIT PET.

Methods: Twenty-four patients with inconclusive parkinsonian features at initial clinical evaluation and nine healthy controls were studied. Patients consisted of three subgroups: nine patients whose diagnoses were unclear concerning whether they had idiopathic Parkinson's disease or drug-induced parkinsonism ('PD/DIP'), nine patients who fulfilled neither the diagnostic criteria of PD nor of essential tremor ('PD/ET'), and six patients who were alleged to have either PD or atypical parkinsonian syndrome ('PD/APS'). Brain PET images were obtained 120 min after injection of 185 MBq [(18)F]FP-CIT. Imaging results were quantified and compared with follow-up clinical diagnoses.

Results: Overall, 11 of 24 patients demonstrated abnormally decreased DAT availability on the PET scans, whereas 13 were normal. PET results could diagnose PD/DIP and PD/ET patients as having PD in six patients, DIP in seven, and ET in five; however, the diagnoses of all six PD/APS patients remained inconclusive. Among 15 patients who obtained a final follow-up diagnosis, the image-based diagnosis was congruent with the follow-up diagnosis in 11 patients. Four unsolved cases had normal DAT availability, but clinically progressed to PD during the follow-up period.

Conclusion: [(18)F]FP-CIT PET imaging is useful in the differential diagnosis of patients with inconclusive parkinsonian features, except in patients who show atypical features or who eventually progress to PD.
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June 2014

Lateralization of cognitive functions in aphasia after right brain damage.

Yonsei Med J 2012 May;53(3):486-94

Department of Speech Pathology, Daegu University, Gyeongsan, Korea.

Purpose: The lateralization of cognitive functions in crossed aphasia in dextrals (CAD) has been explored and compared mainly with cases of aphasia with left hemisphere damage. However, comparing the neuropsychological aspects of CAD and aphasia after right brain damage in left-handers (ARL) could potentially provide more insights into the effect of a shift in the laterality of handedness or language on other cognitive organization. Thus, this case study compared two cases of CAD and one case of ARL.

Materials And Methods: The following neuropsychological measures were obtained from three aphasic patients with right brain damage (two cases of CAD and one case of ARL); language, oral and limb praxis, and nonverbal cognitive functions (visuospatial neglect and visuospatial construction).

Results: All three patients showed impaired visuoconstructional abilities, whereas each patient showed a different level of performances for oral and limb praxis, and visuospatial neglect.

Conclusion: Based on the analysis of these three aphasic patients' performances, we highlighted the lateralization of language, handedness, oral and limb praxis, visuospatial neglect and visuospatial constructive ability in aphasic patients with right brain damage.
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May 2012