Nicola Giannini

Genetics of ischaemic stroke in young adults

Background Stroke may be a clinical expression of several inherited disorders in humans. Recognition of the underlined genetic disorders causing stroke is important for a correct diagnosis, for genetic counselling and, even if rarely, for a correct therapeutic management. Moreover, the genetics of complex diseases such the stroke, in which multiple genes interact with environmental risk factors to increase risk, has been revolutionized by the Genome-Wide Association Study (GWAS) approach. Scope of review Here we review the single-gene causes of ischemic stroke, bringing the reader from the candidate gene method toward the exciting new horizons of genetic technology. Major conclusions The aetiological diagnosis of ischemic stroke in young adults is more complex than in the elderly. The identification of a genetic cause is important to provide appropriate counseling and to start a correct therapy, when available. The advent of GWAS technology, such as for other complex pathological conditions, has contributed enormously to the understanding of many of these genetic bases. For success large, well phenotyped case cohorts are required, and international collaborations are essential. General significance This review focuses on the main causes of genetically-based ischemic stroke in young adults, often classified as indeterminate, investigating also the recent findings of the GWAS, in order to improve diagnostic and therapeutic management.

Cerebral lateralization for language in deaf children with cochlear implantation.

Functional Transcranial Doppler ultrasonography (fTCD) was used to investigate the effects of early acoustic deprivation and subsequent reafferentation on cerebral dominance for language in deaf children provided with Cochlear Implantation (CI). Twenty children with CI (13 in right ear and 7 in left ear) and 20 controls matched for age, sex and handedness were administered a fTCD animation description task. Left hemisphere dominance for language with comparable mean Laterality Indexes (LIs) was found in children with CI and controls; right-ear implanted subjects showed cerebral activation controlateral to implanted ear more frequently than left-ear implanted ones. Linguistic proficiency of CI recipients was below age expectation in comparison to controls; language scores did not significantly differ between children with left and right LI, whereas both age and side of implantation were significantly related to language outcome. Theoretical implication and potential clinical application of fTCD in CI management are discussed.

Cerebral sinus venous thrombosis: clinical and pathogenetic perspectives from Tuscany

Cerebral sinus venous thrombosis (CSVT) is a rare condition representing the 0.5–1% of all stroke cases which can have serious consequences. Early diagnosis and complete screening for acquired or inherited risk factors is crucial for decreasing morbidity and mortality. We have investigated clinical and aetiological factors in an Italian cohort of 43 patients with cerebral sinus venous thrombosis. Common presentation complaints were headache (81.4%), focal signs (20.9%), vomiting (11.6%) and seizures (6.9%). Acquired or inherited conditions were observed in more than 80% of cases. The commonest aetiological factors were contraceptives (74.1% of women), congenital thrombophilia (34.9%), infections and dysthyroidism (16.3%), hyperhomocysteinemia (9.3%), migraine (11.6%), cranial trauma (9.3%) and chronic myeloproliferative diseases (11.6%). Outcome was favourable in more than 80% of patients. Early diagnosis and anticoagulant treatment may decrease mortality and/or morbidity rates related with CVST in these patients. Thrombophilic abnormalities, either inherited or acquired, are worthy to be widely investigated.

Hemispheric language organization after congenital left brain lesions: A comparison between functional transcranial Doppler and functional MRI

This study investigated whether functional transcranial Doppler ultrasound (fTCD) is a suitable tool for studying hemispheric lateralization of language in patients with pre-perinatal left hemisphere (LH) lesions and right hemiparesis. Eighteen left-hemisphere-damaged children and young adults and 18 healthy controls were assessed by fTCD and fMRI to evaluate hemispheric activation during two language tasks: a fTCD animation description task and a fMRI covert rhyme generation task. Lateralization indices (LIs), measured by the two methods, differed significantly between the two groups, for a clear LH dominance in healthy participants and a prevalent activation of right hemisphere in more than 80% of brain-damaged patients. Distribution of participants in terms of left, right, and bilateral lateralization was highly concordant between fTCD and fMRI values. Moreover, right hemisphere language dominance in patients with left hemispheric lesions was significantly associated with severity of cortical and subcortical damage in LH. This study suggests that fTCD is an easily applicable tool that might be a valid alternative to fMRI for large-scale studies of patients with congenital brain lesions.

Functional magnetic resonance imaging with encoding task in patients with mild cognitive impairment and different severity of leukoaraiosis

Leukoaraiosis is one of the main contributors to mild cognitive impairment due to vascular damage (vascular MCI, VMCI), whose pathophysiology has not been fully elucidated yet. We aimed to shed light on such issue using functional MRI (fMRI). Sixteen patients with VMCI were enrolled and compared with twenty-five patients with MCI but without significant vascular damage (non-vascular MCI, NVMCI) and with fifteen healthy controls (HC). They all underwent fMRI with incidental verbal learning paradigm, using a 3T scanner. Differently from cases with NVMCI (versus HC), VMCI patients presented a higher BOLD activation in the right parieto-occipital cortex and a lower activation in the left superior and middle frontal gyri, anterior cingulum and in left fronto-opercular area when compared to HC. Cortical activation evaluated by fMRI may reflect specific patterns of damage and attempt of compensation in patients with MCI and different severity of leukoaraiosis.

Oxidative stress in cerebral small vessel disease dizziness patients, basally and after polyphenol compound supplementation.

Background: Leukoaraiosis (LA) is a common radiological finding in elderly, frequently associated with several clinical disorders, including unexplained dizziness. The pathogenesis of LA is multifactorial, with a dysfunction of cerebral microcirculation resulting in chronic hypoperfusion and tissue loss, with oxidative stress involved in this cascade. Objective: The aim of this study was to analyse some oxidative stress biomarkers in a cohort of LA patients. Method: Fifty-five consecutive patients (33 males, median age 75 years) with LA were recruited. In a subgroup of 33 patients with LA and unexplained dizziness, we have then performed an open study to evaluate if 60-day supplementation with a polyphenol compound may modify these biomarkers and influence quality of life, analysed with the Dizziness Handicap Inventory (DHI) scale. Results: At baseline, blood oxidative stress parameters values were outside normal ranges and compared to matched healthy controls. After the two months supplementation, we observed a significant decrement of advanced oxidation protein products values and a significant improvement of DHI. Conclusion: Oxidative stress biomarkers may be useful to detect redox imbalance in LA and to provide non-invasive tools to monitor disease status and response to therapy.

Aging with Cerebral Small Vessel Disease and Dizziness: The Importance of Undiagnosed Peripheral Vestibular Disorders

Recent studies showed a link between cerebral small vessel white matter disease (SVD) and dizziness: patients whose dizziness cannot be explained by vestibular disease show severe SVD and gait abnormalities; however, little is still known about how SVD can cause this symptom. The primary aim of this study is to examine the possible underlying causes of dizziness in neurovascular patients; this is in order to assess whether treatable causes could be routinely disregarded. A secondary aim is to possibly define a central oculomotor pattern induced per se by SVD. This could help the diagnosis of SVD-related dizziness. In this single-blind prospective study, 60 patients referred to a neurovascular clinic because of dizziness and SVD on imaging were divided into an L-SVD and a H-SVD group (low and high SVD burden, respectively), and then blindly examined with vestibulometric tests. In H-SVD group, the percentage of unexplained dizziness reached 82.8%. There was a higher prevalence of peripheral vestibular abnormalities in the L-SVD patient group (51.6%) than in the H-SVD (17.2%; p = 0.012). We found no differences in central oculomotor findings between the two groups. Although oculomotricity does not show any consistent pattern, a severe SVD can directly represent a cause of dizziness. However, a patient with mild SVD is more likely to suffer by a peripheral vestibular disorder. Therefore, given the high incidence of vestibular disease in neurovascular or geriatric clinics, clinicians should be cautious when ascribing dizziness solely to the presence of SVD as easily treatable peripheral vestibular causes may be missed.

Common Genetic Conditions of Ischemic Stroke to Keep in Mind

Stroke is a complex disease resulting from the interplay of genetics and environment. In some instances (mainly in young adults) stroke is the direct result of a monogenic disease. Among the monogenic causes of stroke, the diseases which are most frequently encountered in the adult general neurological practice are CADASIL, Fabry and mitochondrial diseases. Brain MRI and clinical features may frequently lead to a correct molecular diagnosis. Here we review the single-gene causes of ischemic stroke, with special regard to the associated features which may help in the diagnostic approach.

Transient ischemic attack in hereditary hemorrhagic telangiectasia.

Transient ischemic attack or ischemic stroke in hereditary hemorrhagic telangiectasia (HHT), a rare genetic disease, is frequent in clinical practice and often associated to pulmonary arteriovenous malformations (PAVMs), potentially determining paradoxical cerebral embolism. We describe the case of a 53-year-old woman with a previous history of recurrent epistaxis, admitted to our unit for a transient episode of diplopia and unbalance. Cerebrovascular screening showed the presence of a right to left shunt at saline contrast transcranial Doppler, related to 3 PAVMs detected by subsequent chest computed tomographic scan. Genetic screening evidenced deletion in endoglin gene (ENG), suggesting diagnosis of HHT type 1. Secondary cerebrovascular prevention with antithrombotic therapy was early stopped for the worsening of epistaxis. Neurologic symptoms are common in HHT, and saline contrast transcranial Doppler can be a reliable alternative to echocardiography for detection of right to left shunt commonly related to underlying PAVMs.

Intravenous thrombolysis for ischaemic stroke in Down syndrome.

Intravenous thrombolysis with rtPA is the most effective treatment for acute ischaemic stroke with low rates of symptomatic intracerebral haemorrhage (sICH) [1]. Ischaemic stroke is not rare in patients with Down syndrome (DS), especially in association with congenital embolic cardiac disease [2]. DS, by itself, is not a contraindication for intravenous thrombolysis but it might present a raised risk of sICH in relation to concomitant haemorragic-prone conditions: sporadic cerebral amyloid angiopathy (CAA) or Moya–Moya disease [3]. We describe the case of a middle-aged woman with Down syndrome treated with intravenous thrombolysis in the 3-h therapeutic window.