K.S. Wong

Cognitive impairment and functional outcome after stroke associated with small vessel disease

Objectives: Although stroke associated with small vessel disease (SSVD) can induce both motor and cognitive impairment, the latter has received less attention. We aimed to evaluate the frequency of the varying severity levels of cognitive impairment, the determinants of severe cognitive impairment, and the association of cognitive impairment with functional outcome after SSVD. Methods: Consecutive patients admitted to hospital because of SSVD were assessed at 3 months after stroke. We performed a semi-structured clinical interview to screen for cognitive symptoms. Severity of cognitive symptoms was graded according to the Clinical Dementia Rating Scale (CDR). Performance on psychometric tests (Mini-Mental State Examination, Alzheimer’s Disease Assessment Scale (cognition subscale), Mattis Dementia Rating Scale (initiation/perseverence subscale; MDRS I/P)) of patients of different CDR gradings was compared with that of 42 healthy controls. Basic demographic data, vascular risk factors, stroke severity (National Institute of Health Stroke Scale; NIHSS), pre-stroke cognitive decline (Informant Questionnaire on Cognitive Decline in the Elderly; IQCODE), functional outcome (Barthel index; BI), Instrumental Activities Of Daily Living; IADL), and neuroimaging features (site of recent small infarcts, number of silent small infarcts, white matter changes) were also compared among the groups. Regression analyses were performed to find predictors of severe cognitive impairment and poor functional outcome. Results: Among the 75 included patients, 39 (52%) complained of cognitive symptoms. The number of patients in each CDR grading was as follows: 39 (52%) had a CDR of 0, 26 (34.7%) had a CDR of 0.5, 10 (13.3%) had a CDR of ⩾1. Pre-stroke IQCODE and previous stroke predicted CDR⩾1. The NIHSS was associated with more impaired BI. The NIHSS and MDRS I/P contributed most to impaired IADL. Conclusions: Half of the patients with SSVD complained of varying severity of cognitive problems 3 months after stroke. Pre-stroke cognitive decline and previous stroke predict severe cognitive impairment post stroke. Stroke severity and executive dysfunction contribute most to a poor functional outcome.

Middle cerebral artery occlusion after recent mycoplasma pneumoniae infection

Stroke is a rare complication of Mycoplasma pneumoniae infection although recent studies suggest that infection may be a risk factor of acute ischemic stroke. We report a 5-year-old girl who had a stroke 10 days after M. pneumoniae infection. This is the first case of documented middle cerebral artery occlusion after Mycoplasma infection in children. In this article, we review other published reports on this topic and discuss the possible underlying mechanisms of the middle cerebral artery occlusion.

Variability of Magnetic Resonance Angiography and Computed Tomography Angiography in Grading Middle Cerebral Artery Stenosis

BACKGROUND AND PURPOSEnMagnetic resonance angiography and computed tomography angiography are new, noninvasive methods to provide images of the cerebral vasculature. The reliability of magnetic resonance angiography and computed tomography angiography when used to grade middle cerebral artery stenosis remains to be established. We sought to study the interobserver and intraobserver variabilities of magnetic resonance angiography and computed tomography angiography in grading middle cerebral artery stenosis.nnnMETHODSnA total of 50 middle cerebral arteries in 25 patients were studied with magnetic resonance angiography and computed tomography angiography. All patients had a history of ischemic stroke. The films were read independently by two observers on separate occasions. Films were shown again to the same observer 4 weeks after the first reading. The degree of middle cerebral artery stenosis was categorized into four grades: normal/mild, moderate, severe, and occluded. The interobserver and intraobserver variabilities were calculated by the kappa statistic method.nnnRESULTSnInterobserver variability for grading middle cerebral artery stenosis was good (kappa = 0.78) for magnetic resonance angiography and moderate (kappa = 0.51) for computed tomography angiography. There was perfect agreement between two observers in 86% of the vessels shown in magnetic resonance angiography and in 76% of the vessels shown in computed tomography angiography. Intraobserver variability for both imaging methods was good, with the kappa value in the range of 0.70 to 0.76.nnnCONCLUSIONSnOur results suggest that according to our protocol, magnetic resonance angiography is more reliable than computed tomography angiography in grading middle cerebral artery stenosis.

Recurrence after a first untreated seizure in the Hong Kong Chinese population.

Summary: u2002Purpose: There is wide variation in the reported prognosis after a first unprovoked generalized tonic‐clonic convulsion and in the risk factors that are associated with recurrence. Estimates for the risk of recurrence range from 26 to 71%. We investigated the likelihood of a second attack in Hong Kong Chinese patients.

Poststroke fatigue is associated with caudate infarcts

OBJECTIVEnThe caudate nucleus may be involved in the pathogenesis of the fatigue observed in neurological disorders. However, the significance of caudate lesions in poststroke fatigue (PSF) is unknown. This study examined the association between caudate infarcts and PSF.nnnMETHODSnFive hundred Chinese patients with acute ischemic stroke admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong participated in the study. All participants were assessed for PSF with the Fatigue Severity Scale (FSS) three months after their index stroke. PSF was defined as a mean FSS score of 4.0 or more. Physical functioning and depressive symptoms were measured by the Barthel Index (BI) and the Geriatric Depression Scale (GDS).nnnRESULTSnOne hundred and twenty-five (25.0%) of the patients had PSF. Compared to the non-fatigue group, the PSF patients were more likely to be women and had hyperlipidemia, lower BI and higher GDS scores. Caudate (8.0% versus 1.3%, p=0.001) and putamen (19.2% versus 12.0%, p=0.043) acute infarcts were more common in the PSF group, whereas pons infarcts (13.6% versus 22.2%, p=0.038) were less common. Acute caudate infarcts remained an independent predictor of PSF in the multivariate analysis, with an odds ratio of 6.4.nnnCONCLUSIONSnThe results suggest that patients with PSF are more likely to have caudate infarcts.

Cerebral microbleeds and symptom severity of post-stroke depression: A magnetic resonance imaging study

BACKGROUNDnCerebral microbleeds (CMBs) are common in stroke survivors, although their clinical significance in the development of psychiatric conditions following stroke remains unknown. This study examines the association between post-stroke depression (PSD) symptom severity and CMBs.nnnMETHODSnAmongst the 4088 patients with acute ischemic stroke who had been admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong, between December 2004 and May 2009, 994 patients were recruited. A psychiatrist administered the Structural Clinical Interview for DSM-IV to all 994 patients and made a diagnosis of PSD three months after the index stroke. PSD symptom severity was assessed with the 15-item Geriatric Depression Scale (GDS). Seventy-eight patients were found to have PSD. The presence and location of CMBs were evaluated with magnetic resonance imaging (MRI).nnnRESULTSnSeventy-eight patients (7.8%) had PSD. CMBs were identified in 20 PSD patients. Relative to the no-CMB group, the mean GDS score of patients with lobar CMBs was significantly higher (12.6±2.6 versus 10.4±2.5, p=0.01 after adjusting for age, sex, global cognitive functions, neurological deficits and white matter hyperintensities).nnnLIMITATIONSnPatients with more severe stroke, those who died before the three-month follow-up and those who became depressed later were excluded, as were those unable to give their consent due to dementia or aphasia. These selection biases may limit the generalizability of the findings.nnnCONCLUSIONSnThe results suggest that lobar CMBs may contribute to PSD symptom severity. The importance of CMBs in the pathogenesis of other psychiatric disorders in stroke survivors and other patient populations warrants further investigation.

Use of Magnetic Resonance Angiography to Predict Long-Term Outcomes of Ischemic Stroke Patients with Concurrent Stenoses in Hong Kong

Purpose: To determine the long-term outcome of ischemic stroke patients with concurrent intracranial and extracranial atherosclerosis using magnetic resonance angiography. Methods: A prospective cohort of patients in Hong Kong with acute ischemic stroke was studied with magnetic resonance angiography of the brain and carotid duplex. All patients were followed up regularly for the development of recurrent stroke, cardiac events, or death. Results: Totally 343 patients with acute ischemic stroke were included, of whom 104 (30%) had concurrent intracranial and extracranial lesions. The follow-up period was up to 76 months (mean 44.5 months). Overall, 55 patients (15.5%) died of any cause and 91 patients (26.5%) suffered a further nonfatal vascular event. The overall 5-year cumulative rates of mortality, restroke and poor outcomes (combined death and further vascular events) were 18, 27 and 37%, respectively. In patients with concurrent lesions, these rates were 31, 41 and 51%, respectively. The corresponding rates were 13, 22 and 31% in patients without concurrent lesions. The risks were highest in the first year after stroke. More deaths (log rank, 16.3; p = 0.0001), restrokes (log rank, 9.71; p = 0.002) and poor outcomes (log rank, 13.87; p = 0.0001) were found among patients with concurrent lesions. The presence of concurrent vascular lesions, advanced age, smoking, hyperlipidemia and previous history of stroke were independent predictors of poor outcomes. Conclusions: The long-term prognosis of ischemic stroke patients with concurrent atherosclerosis of intracranial and extracranial vessels is poor. They are at high risk of further vascular events or death.

Plaque volume measurement by magnetic resonance imaging as an index of remodeling of middle cerebral artery: correlation with transcranial color Doppler and magnetic resonance angiography.

Background: The feasibility of a noninvasive evaluation of remodeling of the middle cerebral artery (MCA) by magnetic resonance imaging (MRI) was assessed. The results were correlated with magnetic resonance angiography (MRA) and transcranial color Doppler (TCD) findings. Methods: 26 patients (13 male and 13 female, age ranged from 46 to 82 years) who presented with symptoms of cerebrovascular accidents had TCD, MRA and MRI assessment of the MCA. The TCD and MRA findings of 40 MCAs accessible by TCD were correlated with the ratio of cross-sectional area of the vessel (VA), luminal area of the vessel (LA) and plaque load (PL). Results: The VA ratio and LA showed no correlation with TCD or MRA results. PL however was shown to be associated with both TCD and MRA. Conclusions: MRI could be used to assess remodeling in MCAs. PL was found to be associated with TCD and MRA findings.

Spiral computed tomography angiography in the assessment of middle cerebral artery occlusive disease.

There has been no report on the use of spiral computed tomography angiography (CTA) in the investigation of intracranial cerebral artery stenosis. A prospective pilot study was conducted to investigate the feasibility of CTA in the diagnosis of intracranial occlusive disease and its correlation with transcranial Doppler. With transcranial Doppler, 10 patients with acute ischaemic stroke with middle cerebral artery stenosis or occlusion were identified. There were seven middle cerebral artery stenoses and five middle cerebral artery occlusions. The CTA confirmed all diagnoses by transcranial Doppler except in one patient with middle cerebral artery occlusion in whom the embolus had probably propagated. The results showed that CTA is feasible and potentially useful in the diagnosis of middle cerebral artery occlusive disease. Further studies are required to assess its validity, sensitivity, and specificity in the diagnosis of middle cerebral artery occlusive disease.

White matter hyperintensities in post-stroke depression: a case control study

Objective Despite extensive research on post-stroke depression (PSD), the role of white matter hyperintensities (WMHs) in its pathogenesis remains uncertain. The aim of this study was to evaluate the relationship between WMHs and PSD in Chinese patients with first or recurrent stroke. Methods A cohort of 994 patients with acute ischaemic stroke admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong was recruited. A psychiatrist administered the Structural Clinical Interview for DSM-IV to all patients and made a diagnosis of PSD 3u2005months after the index stroke. 78 (7.8%) patients had PSD; 78 stroke patients matched according to age and sex but without PSD served as a control group. The severity and location of WMHs were evaluated with MRI. Results In comparison with the non-PSD group, patients in the PSD group were more likely to have severe deep WMHs (12.8% vs 1.3%; p=0.009). Severe deep WMHs remained an independent predictor of PSD in the multivariate analysis with an OR of 13.8 (p=0.016). Conclusion The results suggest that WMHs may play a role in the development of PSD. The importance of WMHs in the treatment and outcome of PSD warrants further investigation.