Cerebral microbleeds (CMBs) are known to be associated with cognitive impairments in the elderly and in patients with various diseases; however, the nature of this association has not yet been evaluated in Parkinson's disease (PD). In the present study, we analyzed the incidence of CMBs in PD according to cognitive status, and the impact of CMBs on cognitive performance was also evaluated. The CMBs in PD with dementia (n = 36), mild cognitive impairment (MCI, n = 46), or cognitively normal (n = 41) were analyzed using conventional T2*-weighted gradient-recalled echo images. Additionally, the relationship between the presence of CMBs and cognitive performance on individual tests of cognitive subdomains was analyzed using a detailed neuropsychological test. CMBs occurred more frequently in PD patients with dementia (36.1 %) compared to those with MCI (15.2 %), those who are cognitively normal (14.6 %), and normal controls (12.2 %, p = 0.025). However, the significant association of CMBs with PD dementia disappeared after adjusting white matter hyperintensities (WMHs) as a covariate. The frequencies of deep, lobar, and infratentorial CMBs did not differ among the four groups. After adjusting for age, sex, years of education, and WMHs, PD patients with CMBs had poorer performance in attention domain compared with those without CMBs (34.9 vs 42.6, p = 0.018). The present data demonstrate that even though CMBs were inseparably associated with the presence of WMHs, CMBs occur more commonly in PD patients with dementia than in those without dementia. Additionally, the burden of CMBs may contribute to further cognitive impairment in PD.

BackgroundThe safety of repeated mechanical thrombectomy within the acute stroke period has not yet been clearly demonstrated. We describe herein a patient who was successfully treated with repeated mechanical thrombectomy within the acute index stroke period.Case ReportA 50-year-old woman with atrial fibrillation presented with left-sided weakness caused by occlusion of the right middle cerebral artery (MCA). Emergent mechanical thrombectomy with the Solitaire device achieved complete recanalization. The left MCA occlusion redeveloped at 6 days after the first treatment, at which time her international normalized ratio (INR) was 2.3. Endovascular thrombectomy was reattempted rapidly and complete recanalization was achieved again. Her neurologic symptoms resolved after the thrombectomy.ConclusionsThis case demonstrates that repeated mechanical thrombectomy can be safely and successfully performed even in a patient with a high INR and a recurrent stroke during the acute period after the index stroke.

In this paper, we report the enhancement of resolution of continuous wave (CW) stimulated emission depletion (STED) microscopy by a novel method of structured illumination of an excitation beam. Illumination by multiple excitation beams through the specific pupil apertures with high in-plane wave vectors leads to interference of diffracted light flux near the focal plane, resulting in the contraction of the point spread function (PSF) of the excitation. Light spot reduction by the suggested standing wave (SW) illumination method contributes to make up much lower depletion efficiency of the CW STED microscopy than that of the pulsed STED method. First, theoretical analysis showed that the full width at half maximum (FWHM) of the effective PSF on the detection plane is expected to be smaller than 25% of that of conventional CW STED. Second, through the simulation, it was elucidated that both the donut-shaped PSF of the depletion beam and the confocal optics suppress undesired contribution of sidelobes of the PSF by the SW illumination to the effective PSF of the STED system. Finally, through the imaging experiment on 40-nm fluorescent beads with the developed SW-CW STED microscopy system, we obtained the result which follows the overall tendency from the simulation in the aspects of resolution improvement and reduction of sidelobes. Based on the obtained result, we expect that the proposed method can become one of the strategies to enhance the resolution of the CW STED microscopy.

Lateral medullary infarction can lead to central respiratory failure. However, in Wallenberg's syndrome, obstructive respiratory failure rarely develops. Here, we report a case of obstructive respiratory failure with stridor caused by unilateral lateral medullary infarction. A 74-year-old woman was admitted for acute right lateral medullary infarction. On the 12th day after the stroke, the patient developed respiratory failure necessitating endotracheal intubation. She could maintain good oxygen saturation and ventilation in intubated status without the assistance of mechanical ventilator, even during sleep. The pharyngo-laryngoscopy demonstrated the hypomobility of bilateral vocal cords. This case suggests that unilateral medullary infarction might be a cause of bilateral vocal cord palsy. (Korean J Stroke 2012;14:89-91)

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