Baseline white matter hyperintensities affect the course of cognitive function after small vessel disease-related stroke: a prospective observational study

Background and purpose

Cognitive impairment is a common sequel of recent small subcortical infarction (RSSI) and might be negatively affected by preexisting cerebral small vessel disease (SVD). We investigated whether the course of cognitive function in patients with RSSI is influenced by the severity of white matter hyperintensities (WMH), an important imaging feature of SVD.

Methods

Patients with magnetic resonance imaging (MRI)‐proven single RSSI were tested neuropsychologically concerning global cognition, processing speed, attention, and set‐shifting. Deep and periventricular WMH severity was assessed using the Fazekas scale, and total WMH lesion volume was calculated from T1‐weighted MRI images. We compared baseline function and course of cognition 15 months after the acute event in patients with absent, mild, and moderate‐to‐severe WMH.

Results

The study cohort comprised 82 RSSI patients (mean age: 61 ± 10 years, 23% female). At baseline, 40% had cognitive impairment (1.5 standard deviations below standardized mean), and deficits persisted in one‐third of the sample after 15 months. After age correction, there were no significant differences in set‐shifting between WMH groups at baseline. However, although patients without WMH (deep: p < 0.001, periventricular: p = 0.067) or only mild WMH (deep: p = 0.098, periventricular: p = 0.001) improved in set‐shifting after 15 months, there was no improvement in patients with moderate‐to‐severe WMH (deep: p = 0.980, periventricular: p = 0.816). Baseline total WMH volume (p = 0.002) was the only significant predictor for attention 15 months poststroke.

Conclusions

This longitudinal study demonstrates that preexisting moderate‐to‐severe WMH negatively affect the restoration of cognitive function after RSSI, suggesting limited functional reserve in patients with preexisting SVD.

Prevalence and short-term changes of cognitive dysfunction in young ischaemic stroke patients

BACKGROUND AND PURPOSE

Information on the prevalence and course of post-stroke cognitive impairment in young stroke patients is limited. The aim was to assess a consecutive sample of acute young ischaemic stroke patients (18-55 years) for the presence and development of neuropsychological deficits.

METHODS

Patients prospectively underwent a comprehensive clinical and cognitive assessment, examining general cognitive function, processing speed, attention, flexibility/executive function and word fluency within the first 3 weeks after hospital admission (median assessment at day 6) and at a 3 months' follow-up (FU). Cognitive dysfunction was defined in comparison to age-standardized published norms.

RESULTS

At baseline (N = 114), deficits were highly prevalent in processing speed (56.0%), flexibility/executive function (49.5%), attention (46.4%) and general cognitive function (42.1%). These frequencies were comparable for those with FU assessment (N = 87). In most domains, cognitive performance improved within 3 months, except for word fluency. However, in about one-third of patients, cognitive deficits (as defined by 1.5 standard deviations below the standardized mean) were still present 3 months after stroke. At FU, 44.0% were impaired in the domain flexibility/executive function, 35.0% in processing speed and 30.0% in attention.

CONCLUSIONS

The high prevalence of cognitive deficits in acute young patients with ischaemic stroke highlights the importance of early post-stroke cognitive assessment to capture a patient's dysfunction in a comprehensive manner and to offer adequate rehabilitation. The role of factors which promote neuropsychological deficits needs further exploration.

Lower Magnetization Transfer Ratio in the Forceps Minor Is Associated with Poorer Gait Velocity in Older Adults

BACKGROUND AND PURPOSE

Gait disturbances in the elderly are disabling and a major public health issue but are poorly understood. In this multimodal MR imaging study, we used 2 voxel-based analysis methods to assess the voxelwise relationship of magnetization transfer ratio and white matter hyperintensity location with gait velocity in older adults.

MATERIALS AND METHODS

We assessed 230 community-dwelling participants of the Austrian Stroke Prevention Family Study. Every participant underwent 3T MR imaging, including magnetization transfer imaging. Voxel-based magnetization transfer ratio-symptom mapping correlated the white matter magnetization transfer ratio of each voxel with gait velocity. To assess a possible relationship between white matter hyperintensity location and gait velocity, we applied voxel-based lesion-symptom mapping.

RESULTS

We found a significant association between the magnetization transfer ratio within the forceps minor and gait velocity (β = 0.134; 95% CI, 0.011-0.258; P = .033), independent of demographics, general physical performance, vascular risk factors, and brain volume. White matter hyperintensities did not significantly change this association.

CONCLUSIONS

Our study provides new evidence for the importance of magnetization transfer ratio changes in gait disturbances at an older age, particularly in the forceps minor. The histopathologic basis of these findings is yet to be determined.

Combined analysis of global and compartmental brain volume changes in early multiple sclerosis in clinical practice

Background:

The extent and clinical significance of brain volume changes in different phases of multiple sclerosis (MS) is still under discussion.

Objective:

To determine the rate of global and compartmental brain volume changes in patients with a clinically-isolated syndrome (CIS) compared to patients with definite MS, by long-term follow-up and as a predictor of conversion to MS in a routine clinical setting.

Methods:

We investigated 120 patients (63 CIS and 57 MS) at baseline and after a mean follow-up period of 43 months, including detailed clinical examination and 3-Tesla magnetic resonance imaging (MRI). Our imaging analyses comprised the normalized brain volume (NBV), cortical grey matter (cGMV) and white matter (WMV) volumes using SIENA/X, the percentage of brain volume change (PBVC) using SIENA and the change in the volume of the thalami (TV) and basal ganglia (BGV). We also determined the amount and change of T2-lesion load (T2-LL).

Results:

At baseline, all the brain volume metrics, except cGMV, were significantly lower; and the T2-LL was significantly higher, in patients with MS rather than CIS. During the follow-up, only the PBVC was higher in MS ( p = 0.008) and this difference was driven by converters from CIS to MS. Quartiles of PBVC did not allow us to predict conversion to MS, but were associated with the degree of disability.

Conclusions:

PBVC is the most sensitive marker of progressing atrophy and a higher PBVC was generally associated with more active disease; however, it did not serve to predict the course of MS on an individual basis, in this study.