Integrity of the hippocampus and surrounding white matter is correlated with language training success in aphasia.

Aphasia after middle cerebral artery (MCA) stroke shows highly variable degrees of recovery. One possible explanation may be offered by the variability of the occlusion location. Branches from the proximal portion of the MCA often supply the mesial temporal lobe including parts of the hippocampus, a structure known to be involved in language learning. Therefore, we assessed whether language recovery in chronic aphasia is dependent on the proximity of the MCA infarct and correlated with the integrity of the hippocampus and its surrounding white matter. Language reacquisition capability was determined after 2weeks of intensive language therapy and 8months after treatment in ten chronic aphasia patients. Proximity of MCA occlusion relative to the internal carotid artery was determined by magnetic resonance imaging (MRI) based on the most proximal anatomical region infarcted. Structural damage to the hippocampus was assessed by MRI-based volumetry, regional microstructural integrity of hippocampus adjacent white matter by fractional anisotropy. Language learning success for trained materials was correlated with the proximity of MCA occlusion, microstructural integrity of the left hippocampus and its surrounding white matter, but not with lesion size, overall microstructural brain integrity and a control region outside of the MCA territory. No correlations were found for untrained language materials, underlining the specificity of our results for training-induced recovery. Our results suggest that intensive language therapy success in chronic aphasia after MCA stroke is critically dependent on damage to the hippocampus and its surrounding structures.

Atrial fibrillation in stroke-free patients is associated with memory impairment and hippocampal atrophy.

AIMS: To determine whether atrial fibrillation (AF) in stroke-free patients is associated with impaired cognition and structural abnormalities of the brain. AF contributes to stroke and secondary cognitive decline. In the absence of manifest stroke, AF can activate coagulation and cause cerebral microembolism which could damage the brain. METHODS AND RESULTS: We cross-sectionally evaluated 122 stroke-free individuals with AF recruited locally within the German Competence Network on AF. As comparator, we recruited 563 individuals aged 37-84 years without AF from the same community. Subjects underwent 3 T magnetic resonance imaging to assess covert territorial brain infarction, white matter lesions, and brain volume measures. Subjects with evidence for stroke, dementia, or depression were excluded. Cognitive function was assessed by an extensive neuropsychological test battery covering the domains learning and memory, attention and executive functions, working memory, and visuospatial skills. Cognitive scores and radiographic measures were compared across individuals with and without AF by stepwise multiple regression models. Stroke-free individuals with AF performed significantly worse in tasks of learning and memory (ß = -0.115, P < 0.01) as well as attention and executive functions (ß = -0.105, P < 0.01) compared with subjects without AF. There was also a trend (P = 0.062) towards worse performance in learning and memory tasks in patients with chronic as compared with paroxysmal AF. Corresponding to the memory impairment, hippocampal volume was reduced in patients with AF. Other radiographic measures did not differ between groups. CONCLUSION: Even in the absence of manifest stroke, AF is a risk factor for cognitive impairment and hippocampal atrophy. Therefore, cognition and measures of structural brain integrity should be considered in the evaluation of novel treatments for AF.

Reperfusion does not improve impaired rapid-onset cortical plasticity in patients with severe stenosis of the internal carotid artery.

BACKGROUND: Severe stenosis of the internal carotid artery (ICA) has been associated with impaired cognition in patients, but its effect on rapid-onset cortical plasticity is not known. Carotid endarterectomy (CEA) in patients with severe ICA stenosis reduces stroke risk, but the impact on cognition or physiology of the respective hemisphere remains controversial. METHODS/RESULTS: 16 patients with severe stenosis of the ICA and 16 age and sex matched controls were included. Rapid-onset cortical plasticity was assessed using the paired-associative stimulation (PAS) protocol. PAS models long-term synaptic potentiation in human motor cortex, combining repetitive stimulation of the peripheral ulnar nerve with transcranial magnetic stimulation of the contralateral motor cortex. Cognitive status was assessed with a neuropsychological test battery. In patients, verbal learning and rapid-onset cortical plasticity were significantly reduced as compared to controls. Identical follow-up tests in 9 of the 16 patients six months after CEA revealed no improvement of cognitive parameters or cortical plasticity. CONCLUSIONS: Decreased rapid-onset cortical plasticity in patients with severe stenosis of the ICA was not improved by reperfusion. Thus, other strategies known to increase plasticity should be tested for their potential to improve cortical plasticity and subsequently cognition in these patients.

Intravenous lacosamide--an effective add-on treatment of refractory status epilepticus.

Status epilepticus (SE) is a frequent neurological emergency requiring immediate treatment. Therapy usually requires intravenous anticonvulsive medication. Lacosamide is a novel anticonvulsant drug that is available as infusion solution. We describe seven patients with focal SE who were treated with intravenous Lacosamide. All patients in our case series were unsuccessfully treated with other antiepileptic drugs before Lacosamide i.v. was added. In all cases, SE was terminated within 24 h after Lacosamide. There were no serious side effects or adverse events attributable to Lacosamide i.v. Our data suggest that Lacosamide might be an effective add-on treatment, if standard drugs fail or are unsuitable.

Structural correlates of functional language dominance: a voxel-based morphometry study.

BACKGROUND AND PURPOSE: The goal of this study was to explore the structural correlates of functional language dominance by directly comparing the brain morphology of healthy subjects with left- and right-hemisphere language dominance. METHODS: Twenty participants were selected based on their language dominance from a cohort of subjects with known language lateralization. Structural differences between both groups were assessed by voxel-based morphometry, a technique that automatically identifies differences in the local gray matter volume between groups using high-resolution T1-weighted magnetic resonance images. RESULTS: The main findings can be summarized as follows: (1) Subjects with right-hemisphere language dominance had significantly larger gray matter volume in the right hippocampus than subjects with left-hemisphere language dominance. (2) Leftward structural asymmetries in the posterior superior temporal cortex, including the planum temporale (PT), were observed in both groups. CONCLUSIONS: Our study does not support the still prevalent view that asymmetries of the PT are related in a direct way to functional language lateralization. The structural differences found in the hippocampus underline the importance of the medial temporal lobe in the neural language network. They are discussed in the context of recent findings attributing a critical role of the hippocampus in the development of language lateralization.