Influence Of White Matter Lesions Research Articles

The influence of white matter lesions on the electric field in transcranial electric stimulation

BackgroundTranscranial direct current stimulation (tDCS) is a promising tool to enhance therapeutic efforts, for instance, after a stroke. The achieved stimulation effects exhibit high inter-subject variability, primarily driven by perturbations of the induced electric field (EF). Differences are further elevated in the aging brain due to anatomical changes such as atrophy or lesions. Informing tDCS protocols by computer-based, individualized EF simulations is a suggested measure to mitigate this variability. ObjectiveWhile brain anatomy in general and specifically atrophy as well as stroke lesions are deemed influential on the EF in simulation studies, the influence of the uncertainty in the change of the electrical properties of the white matter due to white matter lesions (WMLs) has not been quantified yet. MethodsA group simulation study with 88 subjects assigned into four groups of increasing lesion load was conducted. Due to the lack of information about the electrical conductivity of WMLs, an uncertainty analysis was employed to quantify the variability in the simulation when choosing an arbitrary conductivity value for the lesioned tissue. ResultsThe contribution of WMLs to the EF variance was on average only one tenth to one thousandth of the contribution of the other modeled tissues. While the contribution of the WMLs significantly increased (p≪.01) in subjects exhibiting a high lesion load compared to low lesion load subjects, typically by a factor of 10 and above, the total variance of the EF didnot change with the lesion load. ConclusionOur results suggest that WMLs do not perturb the EF globally and can thus be omitted when modeling subjects with low to medium lesion load. However, for high lesion load subjects, the omission of WMLs may yield less robust local EF estimations in the vicinity of the lesioned tissue. Our results contribute to the efforts of accurate modeling of tDCS for treatment planning.

The Influence of White Matter Lesions on the Electric Field in Transcranial Electric Stimulation

The Influence of White Matter Lesions on the Electric Field in Transcranial Electric Stimulation

Influence of white matter lesions on the prognosis of acute cardioembolic stroke without reperfusion therapy

BackgroundFew studies have investigated the influence of white matter lesions (WMLs) on the prognosis of acute cardioembolic stroke (CES). We aimed to explore the role of WMLs in predicting 3-month prognosis of CES without reperfusion therapy.MethodsA number of 251 acute CES patients without reperfusion therapy at a single center were retrospectively recruited. The severity of WMLs was evaluated by Fazekas scale and patients were divided into mild WMLs group (188 cases, Fazekas ≤ 2 points) and moderate to severe WMLs group (63 cases, Fazekas ≥ 3 points) accordingly. General data and clinical features of the two groups were compared. Functional outcomes of patients were followed up for 3 months using the modified Rankin scale (mRS) and patients were divided into poor outcome group (mRS ≥ 3) and favorable outcome group (mRS ≤ 2). The effect of WMLs on the prognosis was identified by binary logistic regression.ResultsPatients in moderate to severe WMLs group were older (P < 0.001). Also, they had higher baseline National Institutes of Health Stroke Scale (NIHSS) score (P < 0.001) and elevated incidence of asymptomatic cerebral hemorrhage (P = 0.040) and stroke associated pneumonia (P = 0.001) than those in mild WMLs group. At 3 months, there were 100 cases in the poor outcome group. Patients in poor outcome group had higher baseline NIHSS score, increased proportion of moderate to severe WMLs, and elevated incidence of stroke associated pneumonia than those in favorable outcome group (P < 0.001). Binary logistic regression analysis showed that moderate to severe WMLs (odds ratio [OR] = 4.105, 95 % confidence interval [CI] = 1.447–11.646), baseline NIHSS score (OR = 1.368, 95 % CI = 1.240–1.511), and stroke-associated pneumonia (OR = 4.840, 95 %CI = 1.889–12.400) were independent risk factors for poor outcome.ConclusionsModerate to severe WMLs is an independent risk factor for prognosis of CES patients without reperfusion therapy.

P193 A group-level sensitivity analysis to assess the influence of white matter lesions on the electrical field in simulations of transcranial electric stimulation

P193 A group-level sensitivity analysis to assess the influence of white matter lesions on the electrical field in simulations of transcranial electric stimulation

Influence of cerebral white matter lesions on the activities of daily living of older patients with mild stroke.

Neurological symptom severity is a prognostic factor for post-stroke activities of daily living (ADL). Recently, it has been reported that white matter lesions indicate poor functional prognosis in patients with stroke. The present study investigated the influence of white matter lesions on the ADL of older patients with stroke who have mild neurological symptoms. We investigated ADL at discharge in 44 patients with stroke (men, n = 27; women, n = 17; mean age 78 years [range 71-85 years]) aged ≥65 years with National Institutes of Health Stroke Scale scores of ≤5 (cerebral infarction, n = 37; cerebral hemorrhage, n = 7). We used single correlation analysis and multiple regression analysis to investigate factors that correlated with ADL at discharge. ADL at discharge was also evaluated on the basis of white matter lesion severity (Fazekas classification, grades 0-3). Single correlation analysis showed that age (r = -0.36, P = 0.016), male sex (r = 0.362, P = 0.016), neurological symptom severity (r = -0.361, P = 0.016), ADL on starting rehabilitation (r = 0.685, P < 0.001) and white matter lesion severity (r = -0.361, P = 0.016) significantly correlated with ADL at discharge. Multiple regression analysis showed that ADL on starting rehabilitation (β = 0.519, t = 4.723, P < 0.001) and white matter lesion severity (β = -0.309, t = -3.057, P < 0.01) were statistically significant prognostic factors for ADL at discharge. ADL at discharge score was significantly lower in the group with high white matter lesion severity (Fazekas, grade 2) than in the other two groups (Fazekas, grade 0, P < 0.01; Fazekas, grade 1, P < 0.05). Severe white matter lesions are a prognostic factor for poor ADL at discharge in older patients with stroke who have mild neurological symptoms. Geriatr Gerontol Int 2016; 16: 942-947.

DEPRESSIVE SYMPTOMS IN LATE LIFE AND CEREBROVASCULAR DISEASE: THE IMPORTANCE OF INTELLIGENCE AND LESION LOCATION

The influence of white matter lesions on depressive symptoms in healthy ageing populations remains unclear. In this study, we examined the relationship between depressive symptoms and magnetic resonance imaging (MRI) detected cerebrovascular disease in a normal population living independently in the community, and measured the influence of location of brain abnormalities, fluid intelligence, living alone, and sex. Prospective cohort: 497 community dwelling individuals all born in 1936, who took part in the Scottish Mental Survey of 1947, were followed up in 2000 and at biannual intervals in a longitudinal study of health and cognitive aging. Two hundred forty-four volunteered for brain MRI in 2004-2006. Suitable data were available in 219/244, of whom 115 were men. Brain hyperintensities in lobar white matter, basal ganglia , periventricular, and infratentorial regions were measured using Scheltens' scale. Depressed mood was assessed using the Hospital Anxiety and Depression Scale (HADS) on three biannual intervals. Relationships between Scheltens' scores, HADS-D scores, fluid intelligence, living alone, and sex were assessed using general linear modeling. The main predictor of depressive symptom scores was poorer fluid intelligence (partial η(2) =0.023-0.028, P < .05). Ischemic change in the brainstem (partial η(2) = 0.026, P ≤.05) and basal ganglia (partial η(2) =0.018, P ≤ .05) also predicted HADS-D scores. There was no relationship with sex or living alone. Hyperintensities in the brainstem and basal ganglia are associated with depressive symptoms. Higher fluid intelligence is associated with lower depressive symptoms in this normal, ageing population.

White matter lesions and intra-arterial thrombolysis

The aim of the study was to assess the influence of white matter lesions in patients with acute ischemic stroke treated with intra-arterial thrombolysis (IAT). From September 2003 to January 2010, we treated 400 patients with IAT at our institution. Of these patients, 292 were evaluated with MRI scans and included in this observational study. Clinical data were collected prospectively. Outcome after 3 months was measured with the modified Rankin Scale (mRS); mRS 0-1 was considered as favorable outcome. White matter lesions were scored visually by two observers using the semiquantitative Scheltens and Fazekas scores. Logistic regression analysis was used to identify the association of white matter lesions and clinical outcome, recanalization, and cerebral hemorrhage. The severity of white matter lesions was inversely correlated with favorable outcome, survival and successful recanalization. White matter lesions were an independent predictor of outcome (OR 0.569, p = 0.007) and survival (OR 0.550, p = 0.018) and a weak but independent predictor for recanalization (OR 0.949, p = 0.038). Asymptomatic intracerebral bleeding after IAT was associated with white matter lesions in the basal ganglia in the univariate analysis (p = 0.036), but not after multivariable analysis. The severity of white matter lesions independently predicts clinical outcome and survival in patients treated with IAT. White matter lesions are also a weak but independent predictor for recanalization. Symptomatic intracranial bleeding after IAT are not associated with white matter lesions. Therefore, white matter lesions should not be considered as a contraindication against IAT.

White matter hyperintensities and cognitive dysfunction in Alzheimer's disease

Background: The effect of white matter lesions or vascular atherosclerosis on cognitive function is not fully understood. In this investigation the authors examined the influence of white matter lesions or cerebrovascular stenosis on cognitive decline in Alzheimer's disease. Methods: 137 patients (42 men, mean age 64.6±8.8 years; mean education period 8.0±4.9 years) were included; all were diagnosed as having Alzheimer disease at Seoul National University Hospital. Patients were divided into four groups based on the severities of white matter hyperintensities, the presence of vascular stenosis, or lacunar infarction in brain magnetic resonance (MR) images, and Mini-Mental Status Examination (MMSE) scores and Clinical Dementia Ratings (CDR) were compared.

White Matter Hyperintensities and Cognitive Dysfunction in Alzheimer Disease

The effect of white matter lesions in magnetic resonance imaging or vascular atherosclerosis on cognitive function is not fully understood in Alzheimer disease (AD). In this investigation, we examined the influence of white matter lesions on cognitive decline in AD. A total of 142 patients with AD (44 men, mean age 65.7 + 7.6 years; mean education period 7.8 + 5.0 years) were included. Patients were divided into 4 groups based on the severities of white matter hyperintensities (WMH) in brain magnetic resonance images (MRI) using Fazekas scale. Cognitive functions were determined using the Korean version of the Mini-Mental State Examination (K-MMSE) and the Clinical Dementia Rating (CDR) scale before acetylcholinesterase inhibitors were administered. Of the 142 patients, 30% (43/142) had no white matter signal abnormality (grade 0). Fourteen percentage (20/142) were grade 1, 42% (59/142) grade 2, and 14% (20/142) were grade 3. Mean K-MMSE scores declined as MRI grades increased to grade 2 and 3 compared to grade 0 (P < .01). Clinical Dementia Ratings were also aggravated by MRI grade. These results remained significant after adjusting for compounding factors affecting cognitive functions; sex, age, number of years in full-time education, hypertension, diabetes, hypercholesterolemia, smoking, and atrial fibrillation. The presence of WMHs were associated with score of MMSE and CDR impairment in patients with AD. These features could be a correctable factor hastening cognitive decline in AD.

The influence of white matter lesions on neuropsychological functioning in demented and non-demented 85-year-olds.

White matter lesions on computed tomography of the head were studied in relation to neuropsychological functioning in subjects from a representative sample of non-demented (n = 134) and demented (n = 98) 85-year-olds. Non-demented subjects with white matter lesions (n = 46) scored significantly lower in tests of verbal ability (Synonyms), spatial ability (Block Design, Clock Test), perceptual speed (Identical forms), secondary memory (Thurstone Picture Memory), basic arithmetic (Coin Test) and the global cognitive screening test Mini-Mental State Examination than non-demented subjects without white matter lesions (n = 88). Demented subjects with white matter lesions (n = 67) scored significantly lower in tests of spatial ability (Block Design and Clock Test) and secondary memory (free recall in the MIR memory test, Ten-word memory test I and II) and in the Mini-Mental State Examination than demented subjects without white matter lesions (n = 31). It is concluded that white matter lesions contribute to cognitive decline in both non-demented and demented elderly subjects.