Byung-Mo Oh

Effect of transcranial direct current stimulation on motor recovery in patients with subacute stroke.

Kim DY, Lim JY, Kang EK, You DS, Oh MK, Oh BM, Paik NJ: Effect of transcranial direct current stimulation on motor recovery in patients with subacute stroke. Objective: To test the hypothesis that 10 sessions of transcranial direct current stimulation combined with occupational therapy elicit more improvement in motor function of the paretic upper limb than sham stimulation in patients with subacute stroke. Design: Eighteen patients with subacute stroke with hand motor impairment were randomly assigned to one of the three 10-day sessions of (a) anodal transcranial direct current stimulation over the affected motor cortex, (b) cathodal transcranial direct current stimulation over the unaffected motor cortex, or (c) sham stimulation. Blinded evaluators assessed upper limb motor impairment and global functional state with the Fugl-Meyer Assessment score and the Modified Barthel Index at baseline, 1 day after stimulation, and 6 mos after stimulation. Results: Baseline scores for Fugl-Meyer Assessment and Modified Barthel Index were comparable in all groups (P > 0.05). At 6-mo follow-up, cathodal transcranial direct current stimulation led to a greater improvement in Fugl-Meyer Assessment than the sham procedure (P < 0.05). There was a significant inverse correlation between baseline Fugl-Meyer Assessment and Fugl-Meyer Assessment increase at 6 mos (r = −0.846; P < 0.01). Conclusions: Our results suggest a potentially beneficial effect of noninvasive cortical stimulation during rehabilitative motor training of patients who have suffered from subacute strokes.

Functional improvement and neuroplastic effects of anodal transcranial direct current stimulation (tDCS) delivered 1day vs. 1week after cerebral ischemia in rats

Transcranial direct current stimulation (tDCS) is an emerging tool for improving recovery from stroke. However, there has been no trial to determine whether it has a therapeutic benefit in the early stage of cerebral ischemia, and there is no consensus on the optimal time window of stimulation. Here, we described the effects of anodal tDCS in early cerebral ischemia, assessing functional improvements and changes in neuronal plasticity, and identifying the optimal time window for delivering tDCS to maximize functional gains. Thirty rats were randomly assigned to three groups: sham (n=10); early tDCS (ET), receiving tDCS 1day after ischemia for 5 days (n=10), and late tDCS (LT), receiving tDCS 1 week after ischemia for 5 days (n=10). Both ET and LT groups showed improved Barnes maze performance and motor behavioral index scores. However, only the LT group exhibited improvement in beam balance test. Immunohistochemical stainings showed that the ET group reinforced notable MAP-2 expression and the LT group enhanced mainly the level of GAP-43 in both peri-lesional and contralesional cortex. These immunohistochemical results had significant correlation with behavioral and cognitive functions. However, brain MRI and (1)H MRS showed no significant differences among the three groups in ischemic volume and metabolic alteration. These results suggest that anodal tDCS has the potential to modulate neural plasticity around the ischemic penumbra and even in the contralesional area without aggravating infarction volume and metabolic alteration. The degree of functional improvement was slightly greater when tDCS was applied 1 week rather than 1 day after ischemic injury.

RECOVERY OF SWALLOWING FUNCTION IS ACCOMPANIED BY THE EXPANSION OF THE CORTICAL MAP

To determine whether multiple sessions of electrical stimulation (ES) applied to neck muscles improve swallowing function and whether this improvement is accompanied by cortical reorganization in patients with dysphagia, before-after trials were performed on eight subjects. ES was applied for 1 hour, 5 days a week for 2 weeks. Swallowing function significantly improved after 2 weeks of ES, and this change was found to correlate with cortical reorganization measured by corticobulbar output maps. This study suggests that multiple sessions of ES applied to the neck muscles improve swallowing function via a mechanism involving long-term cortical reorganization.

Influence of Aging on Movement of the Hyoid Bone and Epiglottis during Normal Swallowing: A Motion Analysis

Background: The age-related effects on various aspects of swallowing have been reported in studies on the temporal relationship between hyolaryngeal movement and bolus location, as well as the extent of hyolaryngeal movement. However, few studies have described the temporal and spatial relationships concurrently. Objective: The main purpose of this study was to define the kinematics of the hyoid bone and epiglottis, during swallowing, on the temporal and spatial relationships concurrently in healthy subjects, and to investigate the influence of aging on hyolaryngeal movement. Methods: We performed a two-dimensional motion analysis of the hyoid bone and epiglottis using videofluoroscopy images in 69 normal subjects. The trajectories of the hyolaryngeal movement and passage of a bolus were superimposed to form one plot. Temporal measurements included initiation and duration of the hyoid bone and epiglottis movement compared to their movement with the bolus. The spatial measurements included vertical and horizontal excursion of the hyoid bone, and the rotational angle of the epiglottis. Results: The duration of supraglottis closure, and the maximal vertical excursion of the hyoid bone were increased in older subjects, more than 65 years of age, compared to younger subjects (p < 0.05). Other temporal and spatial measurements were not statistically significant in the comparisons among the age groups. The vertical distance of the cervical vertebra was related to vertical excursion of the hyoid bone (p = 0.002), and the horizontal distance from the chin to the cervical vertebra was related to the horizontal excursion of the hyoid bone (p = 0.003). Conclusion: This paper describes a method for assessing temporal and spatial relationships of hyolaryngeal movement, and the passage of a bolus during swallowing. The two-dimensional kinematic swallowing motion analyses that were developed provided useful data that changed with age.

CENTRAL EFFECT OF BOTULINUM TOXIN TYPE A IN HUMANS

This study investigated the changes in the cortical excitability with a paired-pulse transcranial magnetic stimulation (TMS) model after a botulinum toxin type A (BTA) injection in normal humans. Ten healthy subjects were enrolled in the study, which involved applying paired TMS to the motor cortex and recording the motor evoked potentials (MEP) before and after the BTA injection. BTA (2.5 mouse units) was injected into the right extensor digitorium brevis muscle. The amplitudes of MEP during rest and the cortical silent period (CSP) for the period of the tonic muscle contraction were measured at an interstimulus interval (ISI) of 3 ms and 20 ms. One month and three months after BTA injection, the level of intracortical inhibition increased significantly at an ISI of 3 ms and the intracortical facilitation decreased at an ISI of 20 ms. The duration of CSP shortened significantly at an ISI of 3 ms 1 month after BTA injection, which was also shortened significantly at an ISI of 20 ms. These findings were maintained until 3 months after the injection. It was concluded that cortical excitability could be modified by BTA injection in normal humans.

Factors associated with compliance with viscosity-modified diet among dysphagic patients.

Objective To investigate compliance with a viscosity-modified diet among Korean dysphagic patients and to determine which factors are associated with compliance. Methods We retrospectively reviewed medical records of patients who had been recommended to use thickeners in the previous videofluoroscopic swallowing study (VFSS). Among 68 patients, 6 were excluded because tube feeding was required due to deterioration in their medical condition. Finally, 62 patients were included in the study. Patient compliance was assessed using their medical records by checking whether he or she had maintained thickener use until the next VFSS. To determine which factors affect compliance, the relationship between thickener use and patient characteristics, such as sex, age, inpatient/outpatient status, severity of dysphagia, aspiration symptoms, follow-up interval of VFSS, and current swallowing therapy status were assessed. For noncompliers, reasons for not using thickeners were investigated by telephone interview. Results Among 62 patients, 35 (56.5%) were compliers, and 27 (43.5%) were noncompliers. Eighteen (90%) of 20 inpatients had followed previous recommendations; however, only 17 (40.5%) of 42 outpatients had been using thickeners. Of patient characteristics, only admission status was significantly correlated with compliance. When asked about the reason why they had not used thickeners, noncompliers complained about dissatisfaction with texture and taste, greater difficulty in swallowing, and inconvenience of preparing meals. Conclusion Among Korean dysphagic patients, compliance with a viscosity-modified liquid diet was only about 50%. Betterments of texture and taste along with patient education might be necessary to improve compliance with thickener use.

Spatiotemporal characteristics of swallowing in Parkinson's disease.

The aim of this study was to quantitatively investigate spatiotemporal movement abnormalities during the pharyngeal phase of swallowing in individuals with Parkinsons disease (PD) and to investigate relationships between disease and dysphagia severities.

Validity and Reliability of the Korean Version of the MD Anderson Dysphagia Inventory for Head and Neck Cancer Patients

Objective To translate the MD Anderson Dysphagia Inventory (MDADI) which is a self-administered questionnaire that assesses effect of dysphagia on the quality of life for patients with head and neck cancer, into Korean and to verify the validity and reliability of the Korean version of MDADI. Methods We performed 6 steps for the cross-cultural adaptation which consisted of translation, synthesis, back translation, review by an expert committee, cognitive debriefing, and final proof reading. A total of 34 dysphagia patients with head and neck cancers from Seoul National University Hospital answered the translated version of the questionnaire for the pre-testing. The patients answered the same questionnaire 2 weeks later to verify the test-retest reliability. Results One patient was excluded at second survey because he changed his feeding strategy. Overall, 33 patients completed the study. Linguistic validations were achieved by each step of cross-cultural adaptation. We gathered statistically strong construct validity (Spearman rho for subdomain scores to total score correlation range from 0.852 to 0.927), internal consistency for subdomains (Cronbachs alpha coefficients range from 0.785 to 0.889) and test-retest reliability (intra-class correlation coefficient range from 0.820 to 0.955) Conclusion The Korean version of the MDADI achieved linguistic validations and demonstrated good construct validity and reliability. It can be a useful tool for screening and treatment planning for the dysphagia of patients with head and neck cancers.

The Accuracy of the Swallowing Kinematic Analysis at Various Movement Velocities of the Hyoid and Epiglottis

Objective To evaluate the accuracy of the swallowing kinematic analysis. Methods To evaluate the accuracy at various velocities of movement, we developed an instrumental model of linear and rotational movement, representing the physiologic movement of the hyoid and epiglottis, respectively. A still image of 8 objects was also used for measuring the length of the objects as a basic screening, and 18 movie files of the instrumental model, taken from videofluoroscopy with different velocities. The images and movie files were digitized and analyzed by an experienced examiner, who was blinded to the study. Results The Pearson correlation coefficients between the measured and instrumental reference values were over 0.99 (p<0.001) for all of the analyses. Bland-Altman plots showed narrow ranges of the 95% confidence interval of agreement between the measured and reference values as follows: 0.14 to 0.94 mm for distances in a still image, -0.14 to 1.09 mm/s for linear velocities, and -1.02 to 3.81 degree/s for angular velocities. Conclusion Our findings demonstrate that the distance and velocity measurements obtained by swallowing kinematic analysis are highly valid in a wide range of movement velocity.

Cauda equina syndrome misdiagnosed as aggravated hydrocephalus: neurological complication of intrathecal colistin in post-surgical meningitis

Dear Editor, We report a man who experienced a cauda equina syndrome secondary to intrathecal (IT) injection of colistimethate sodium (colistin) for the treatment of postneurosurgical meningitis with multi-drug-resistant (MDR) Acinetobacter baumannii. The patient missed opportune diagnosis due partly to the complexity of clinical circumstances and partly to the lack of previous reports of a cauda equina syndrome as a direct neurological complication of IT colistin.