Design and Evaluation of Korean Electropalatography (K-EPG).

Recently, the development of medical rehabilitation technology has resulted in an increased interest in speech therapy equipment. In particular, research on articulation therapy for communication disorders is being actively conducted. The existing methods for the diagnosis and treatment of speech disorders, such as traditional tactile perception tests and methods based on the empirical judgment of speech therapists, have many limitations. Moreover, the position and contact force of the tongue are key factors in speech disorders with regards to articulation. This is a very important factor in the distinction of Korean characters such as lax, tense and aspirated consonants. In this study, we proposed a Korean-electropalatography (EPG) system to easily measure and monitor the position and contact force of the tongue during articulation treatment and diagnosis. In our proposed K-EPG system, a sensor was fabricated using an AgCl electrode and biocompatible silicon. Furthermore, the measured signal was analyzed by implementing a bio-signal processing module and monitoring program. In particular, the bio-signal was measured by inserting the device into the palate of an experimental healthy test group (four subjects). Through these experiments, we confirmed that our K-EPG system could be applied to clinical treatment in speech therapy.

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

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.

Recovery of injured Broca's portion of arcuate fasciculus in the dominant hemisphere in a patient with traumatic brain injury.

RATIONALE: Recovery of injured AF in patients with traumatic brain injury (TBI) has not been reported. In this study, we report on a patient with TBI who recovered from an injury to Broca's portion of AF in the dominant hemisphere, diagnosed by diffusion tensor tractography (DTT). PATIENT CONCERNS: A 28-year-old right-handed male patient suffered head trauma resulting from sliding while riding a motorcycle. DIAGNOSES: He was diagnosed with a traumatic contusional hemorrhage in the left frontal lobe, subarachnoid hemorrhage, and subdural hemorrhage in the left fronto-temporal lobe. INTERVENTIONS: He underwent craniectomy on the left fronto-temporal area, and hematoma removal for the subdural hemorrhage in the neurosurgery department of a university hospital. Two weeks after the injury, he was transferred to the rehabilitation department of another university hospital. He showed severe aphasia and brain MRI showed leukomalactic lesion in the left frontal lobe. OUTCOMES: The result WAB for the patient showed severe aphasia, with an aphasia quotient of 45.3 percentile. However, his aphasia improved rapidly by 9 months with an aphasia quotient at the 100.0 percentile. 2-week DTT detected discontinuity in the subcortical white matter at the branch to Broca's area of left AF. By contrast, on 9-month DTT, the discontinued portion of left AF was elongated to the left Broca's area. LESSONS: Recovery of injured Broca's portion of AF in the dominant hemisphere along with excellent improvement of aphasia was demonstrated in a patient with TBI. This study has important implications in brain rehabilitation because the mechanism of recovery from aphasia following TBI has not been elucidated.

Cued and Un-Cued Semantic Category Fluency in Older Adults with Mild Cognitive Impairment.

BACKGROUND AND PURPOSE: Patients with switching deficits reportedly benefit more from categorical cueing for semantic category fluency than do patients with clustering deficits. We explored the contribution of language ability and executive control on the performance of semantic category fluency in older adults with mild cognitive impairment (MCI) by examining the effects of categorical cueing on the task. METHODS: Order adults with MCI (n=10) and normal controls (n=25) were compared on two versions of a semantic fluency task: a standard, un-cued version (SF) and a version in which subjects were cued (C-SF) with 4 subordinated categories. The scores and error types of SF and C-SF tasks were analyzed between two groups. Also, the correlation among the SF task, the C-SF task, and the confrontation naming task were examined. RESULTS: The performance of the sematic fluency task improved when categorical cues were included in both groups. However, the normal group showed significantly more improvement than the MCI group. Self-repetition errors in the SF task and categorical errors in the C-SF task occurred most frequently. The normal group showed significantly more errors than the MCI group in the C-SF task. There was a positive correlation among the SF task, the C-SF task, and the confrontation naming task. CONCLUSIONS: The results of the present study suggested that the MCI group has more difficulty in the semantic memory store rather than in the use of retrieval strategies. A combination of standard and cued semantic fluency tasks may help to confirm the underlying deficit of semantic fluency impairment.

Lateralization of cognitive functions in aphasia after right brain damage.

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.