Alexander Y.L. Lau

Risk factors for incident dementia after stroke and transient ischemic attack

We hypothesized that chronic brain changes are important substrates for incident dementia after stroke and transient ischemic attack (TIA).

Significance of good collateral compensation in symptomatic intracranial atherosclerosis.

Background: Collateral circulation stabilizes cerebral blood flow in patients with acute occlusion, but its prognostic role is less studied in intracranial atherosclerosis and appears different in moderate to severe stenosis. We aimed to study the associations between antegrade flow across stenosis, collateral flow via leptomeningeal anastomosis, and the neurological outcome and recurrence risk in patients with symptomatic intracranial stenosis. Methods: We examined a cohort of consecutive patients admitted for stroke or transient ischemic attack (TIA) with symptomatic intracranial stenosis confirmed by digital subtraction angiography in a single-center retrospective study. Angiograms were graded systematically in a blinded fashion for antegrade and collateral flow, using Thrombolysis in Cerebral Infarction (TICI) and American Society of Intervention and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) grading, respectively, and integrated to a simple composite circulation score. Demographic and clinical variables, modified Rankin Scale (mRS) scores at 3 months, recurrent stroke or TIA in 12 months were collected. Uni- and multivariate analyses were performed to identify independent predictors of good outcome (mRS 0–2) and recurrence in a logistic regression model. Results: Among 69 patients with pure intracranial atherosclerosis ≥50%, compromised antegrade flow (TICI 0–2a) was observed in 26 (36%) patients and was associated with more severe arterial stenosis (mean 86 vs. 74%, p = 0.001). Poor collateral compensation resulting in a poor composite circulation score was observed in 8 (12%) patients. Patients with a good circulation score (n = 61, 88%) had preserved flow, which was associated with more favorable outcome (OR 7.50, 95% CI 1.11–50.7, p = 0.04) and less recurrent TIA or stroke (OR 0.18, 95% CI 0.04–0.96, p = 0.04). Prognosis was not significantly associated with antegrade or collateral grade per se. Conclusion: Good collateral compensations are more important in patients with symptomatic intracranial stenosis and compromised antegrade flow, and are associated with favorable outcome and less recurrence risk. The feasibility of composite flow assessment should be explored in future studies to identify high-risk intracranial stenosis with compromised hemodynamics.

Rituximab reduces attacks in Chinese patients with neuromyelitis optica spectrum disorders.

We evaluated the safety and efficacy of rituximab in seven Chinese patients with neuromyelitis optica (NMO) or neuromyelitis optica syndrome disorders (NMOSD) in a tertiary medical center in Hong Kong. After rituximab induction, five patients became relapse-free and two had 50% reduction of relapses over a median follow-up of 24 months. No further deterioration of functional status, measured by the Expanded Disability Status Scale, was observed in all patients. Infusions were well tolerated except in two patients who developed transient hypotension. Rituximab reduced clinical relapse and prevented neurological deterioration in a small cohort of Chinese patients with NMO or NMOSD.

Montreal Cognitive Assessment: One Cutoff Never Fits All.

Background and Purpose— The objective of this study is to examine the discrepancy between single versus age and education corrected cutoff scores in classifying performance on the Montreal Cognitive Assessment (MoCA) in patients with stroke or transient ischemic attack. Methods— MoCA norms were collected from 794 functionally independent and stroke- and dementia-free persons aged ≥65 years. magnetic resonance imaging was used to exclude healthy controls with significant brain pathology and medial temporal lobe atrophy. Cutoff scores at 16th, 7th, and 2nd percentiles by age and education were derived for the MoCA and MoCA 5-minute Protocol. MoCA performance in 919 patients with stroke or transient ischemic attack was classified using the single and norm-derived cutoff scores. Results— The norms for the Hong Kong version of the MoCA total and domain scores and the total score of the MoCA 5-minute protocol are described. Only 65.1% and 25.7% healthy controls and 45.2% and 19.0% patients scored above the conventional cutoff scores of 21/22 and 25/26 on the MoCA. Using classification with norm-derived cutoff scores as reference, locally derived cutoff score of 21/22 yielded a classification discrepancy of ⩽42.4%. Discrepancy increased with higher age and lower education level, with the majority being false positives by single cutoffs. With the 25/26 cutoff of the original MoCA, discrepancy further increased to ⩽74.3%. Conclusions— Conventional single cutoff scores are associated with substantially high rates of misclassification especially in older and less-educated patients with stroke. These results caution against the use of one-size-fits-all cutoffs on the MoCA.

Acupuncture and Related Therapies for Symptom Management in Palliative Cancer Care: Systematic Review and Meta-Analysis.

AbstractAvailable systematic reviews showed uncertainty on the effectiveness of using acupuncture and related therapies for palliative cancer care.The aim of this systematic review and meta-analysis was to summarize current best evidence on acupuncture and related therapies for palliative cancer care.Five international and 3 Chinese databases were searched. Randomized controlled trials (RCTs) comparing acupuncture and related therapies with conventional or sham treatments were considered. Primary outcomes included fatigue, paresthesia and dysesthesias, chronic pain, anorexia, insomnia, limb edema, constipation, and health-related quality of life, of which effective conventional interventions are limited.Thirteen RCTs were included. Compared with conventional interventions, meta-analysis demonstrated that acupuncture and related therapies significantly reduced pain (2 studies, n = 175, pooled weighted mean difference: −0.76, 95% confidence interval: −0.14 to −0.39) among patients with liver or gastric cancer. Combined use of acupuncture and related therapies and Chinese herbal medicine improved quality of life in patients with gastrointestinal cancer (2 studies, n = 111, pooled standard mean difference: 0.75, 95% confidence interval: 0.36–1.13). Acupressure showed significant efficacy in reducing fatigue in lung cancer patients when compared with sham acupressure. Adverse events for acupuncture and related therapies were infrequent and mild.Acupuncture and related therapies are effective in reducing pain, fatigue, and in improving quality of life when compared with conventional intervention alone among cancer patients. Limitations on current evidence body imply that they should be used as a complement, rather than an alternative, to conventional care. Effectiveness of acupuncture and related therapies for managing anorexia, reducing constipation, paresthesia and dysesthesia, insomnia, and limb edema in cancer patients is uncertain, warranting future RCTs in these areas.

Would Self-Expanding Stent Occlude Middle Cerebral Artery Perforators?

BACKGROUND AND PURPOSE A major concern of intracranial stenting is perforator infarction. It is unclear whether the sustained radial force of a self-expanding stent or subsequent stent restenosis would cause late occlusion of perforators. METHODS We compared the baseline and poststent (>or=4 months) MRI scans of patients who underwent self-expanding stenting for recurrent ischemic symptoms attributed to a MCA stenosis >or=60%. New infarcts in the ipsilateral striatocapsular region were recorded. RESULTS MCA stenting was technically successful in 23 of 24 recruited patients. No new perforator territory infarct was found in follow-up MRI scans of all recruited patients. Postoperatively, all patients reported no further TIA or stroke over a median follow-up of 15 months. CONCLUSIONS The use of a self-expanding stent in patients with high-grade MCA stenosis may not pose a major risk to the perforators.

Long‐term prognosis of Chinese patients with a lacunar infarct associated with small vessel disease: a five‐year longitudinal study

Rationale Lacunar infarct associated with small vessel disease is a common stroke subtype in China and has a favorable short-term prognosis. Data on its long-term prognosis among Chinese patients are lacking. Aims We aimed to study its long-term prognosis and predictors for poor outcomes. Design We followed up to 75 consecutive Chinese stroke patients who had a lacunar infarct for a period of 5 years. Clinical outcomes with respect to mortality and recurrent stroke were noted. We evaluated baseline clinical and imaging predictors for such outcomes using the Cox regression analysis. Study Outcomes Sixteen (21·3%) patients died and 12 (16%) patients had recurrent stroke during follow-up. Twenty-one (28%) patients had combined events of either death and/or recurrent stroke. Univariate Cox regression analysis showed that age, literacy, National Institute of Health Stroke Scale, incident stroke/transient ischemic attack, and white matter lesion volume predicted survival, while, age, National Institute of Health Stroke Scale, systolic blood pressure, hyperhomocysteinemia, silent lacunes, microbleeds, and white matter lesion volume predicted recurrent stroke. Multivariate Cox regression analysis showed that National Institute of Health Stroke Scale (HR 1·25, 95% CI 1·05–1·48) and white matter lesion volume (HR 1·46, 95% CI 1·11–1·92) predicted combined events of mortality and/or recurrent stroke after age adjustment. Conclusion Approximately one in four patients either died and/or had recurrent stroke within 5 years after a lacunar infarct. Age, stroke severity, and volume of white matter lesion predict a poor long-term prognosis.

Wavelet-denoising of electroencephalogram and the absolute slope method: A new tool to improve electroencephalographic localization and lateralization

OBJECTIVE In ictal scalp electroencephalogram (EEG) the presence of artefacts and the wide ranging patterns of discharges are hurdles to good diagnostic accuracy. Quantitative EEG aids the lateralization and/or localization process of epileptiform activity. METHODS Twelve patients achieving Engel Class I/IIa outcome following temporal lobe surgery (1 year) were selected with approximately 1-3 ictal EEGs analyzed/patient. The EEG signals were denoised with discrete wavelet transform (DWT), followed by computing the normalized absolute slopes and spatial interpolation of scalp topography associated to detection of local maxima. For localization, the region with the highest normalized absolute slopes at the time when epileptiform activities were registered (>2.5 times standard deviation) was designated as the region of onset. For lateralization, the cerebral hemisphere registering the first appearance of normalized absolute slopes >2.5 times the standard deviation was designated as the side of onset. As comparison, all the EEG episodes were reviewed by two neurologists blinded to clinical information to determine the localization and lateralization of seizure onset by visual analysis. RESULTS 16/25 seizures (64%) were correctly localized by the visual method and 21/25 seizures (84%) by the quantitative EEG method. 12/25 seizures (48%) were correctly lateralized by the visual method and 23/25 seizures (92%) by the quantitative EEG method. The McNemar test showed p=0.15 for localization and p=0.0026 for lateralization when comparing the two methods. CONCLUSIONS The quantitative EEG method yielded significantly more seizure episodes that were correctly lateralized and there was a trend towards more correctly localized seizures. SIGNIFICANCE Coupling DWT with the absolute slope method helps clinicians achieve a better EEG diagnostic accuracy.

Risk Factors and Cognitive Relevance of Cortical Cerebral Microinfarcts in Patients With Ischemic Stroke or Transient Ischemic Attack

Background and Purpose— It was recently demonstrated that cerebral microinfarcts (CMIs) can be detected in vivo using 3.0 tesla (T) magnetic resonance imaging. We investigated the prevalence, risk factors, and the longitudinal cognitive consequence of cortical CMIs on 3.0T magnetic resonance imaging, in patients with ischemic stroke or transient ischemic attack. Methods— A total of 231 patients undergoing 3.0T magnetic resonance imaging were included. Montreal Cognitive Assessment was used to evaluate global cognitive functions and cognitive domains (memory, language, and attention visuospatial and executive functions). Cognitive changes were represented by the difference in Montreal Cognitive Assessment score between baseline and 28-month after stroke/transient ischemic attack. The cross-sectional and longitudinal associations between cortical CMIs and cognitive functions were explored using ANCOVA and regression models. Results— Cortical CMIs were observed in 34 patients (14.7%), including 13 patients with acute (hyperintense on diffusion-weighted imaging) and 21 with chronic CMIs (isointense on diffusion-weighted imaging). Atrial fibrillation was a risk factor for all cortical CMIs (odds ratio, 4.8; 95% confidence interval, 1.5–14.9; P=0.007). Confluent white matter hyperintensities was associated with chronic CMIs (odds ratio, 2.8; 95% confidence interval, 1.0–7.8; P=0.047). The presence of cortical CMIs at baseline was associated with worse visuospatial functions at baseline and decline over 28-month follow-up (&bgr;=0.5; 95% confidence interval, 0.1–1.0; P=0.008, adjusting for brain atrophy, white matter hyperintensities, lacunes, and microbleeds). Conclusions— Cortical CMIs are a common finding in patients with stroke/transient ischemic attack. Associations between CMI with atrial fibrillation and white matter hyperintensities suggest that these lesions have a heterogeneous cause, involving microembolism and cerebral small vessel disease. CMI seemed to preferentially impact visuospatial functions as assessed by a cognitive screening test.

Comprehensive assessment for autonomic dysfunction in different phases after ischemic stroke

Background and purpose Studies mostly use the analysis of heart rate variability to measure cardiovascular autonomic regulation in ischemic stroke. Besides power spectral analysis of heart rate variability, this study sought to determine whether autonomic function was impaired during different phases in ischemic stroke by Ewings battery of autonomic function tests. Methods Ninety-four patients with ischemic stroke (34 patients in acute phase and 60 patients in chronic phase, average six-months after stroke onset) and thirty-seven elderly controls were recruited. Ewings battery autonomic function tests and power spectral analysis of heart rate variability were performed in all the subjects. Results From power spectral analysis of heart rate variability, stroke patients of both acute and chronic phases had significantly lower low frequency power spectral density than controls. From Ewings battery of autonomic function tests, patients in acute phase showed impairment in two parasympathetic tests (Valsalva ratio: P = 0·002; heart rate response to deep breathing: P < 0·001) and those in chronic phase showed impairment in all parasympathetic tests (all P < 0·05) in comparison with controls. Conclusions The comprehensive assessment indicates that autonomic dysfunction occurs in acute phase of ischemic stroke and may persist up to six-months after stroke. Parasympathetic dysfunction rather than sympathetic dysfunction is predominant after ischemic stroke.