Hippocampal infarction: redefining transient global amnesia.

BACKGROUND AND AIMS: Transient global amnesia (TGA) is a clinical syndrome characterized by sudden anterograde amnesia not accompanied by other neurological symptoms. There is no consensus on the underlying pathophysiological mechanism. However, diffusion-weighted imaging (DWI) of the magnetic resonance imaging (MRI) has demonstrated hippocampal lesions in as many as 50% of cases. This paper describes a series of patients with TGA and hippocampal lesions. METHODS: This study assessed vascular risk factors in patients older than age 18 admitted to the Hospital Universitario San Ignacio, Bogota, Colombia, from May 2017 to June 2020 with a diagnosis of TGA and evidence of hippocampal ischemic lesion on 3 Tesla brain MRI. RESULTS: The authors identified 36 patients, 72.2% female, with mean age 62 years. Cardiovascular risk factors, most frequently high blood pressure, carotid disease, and dyslipidemia, were present in 75% of these patients. Hippocampal lesions were unilateral in 80% of cases, with median size 2.5 mm, most frequently located at the hippocampal body. Approximately 14% of patients also presented acute ischemic lesions in locations other than the hippocampus. CONCLUSIONS: TGA is a clinical entity previously considered to have undetermined etiology. The present study used brain MRI to identify a group of patients with hippocampal ischemic lesions, finding associated vascular risk factors in a high proportion of them.

Combining Select Blood-Based Biomarkers with Neuropsychological Assessment to Detect Mild Cognitive Impairment among Mexican Americans.

BACKGROUND: Recent work has supported use of blood-based biomarkers in detection of amnestic mild cognitive impairment (MCI). Inclusion of neuropsychological measures has shown promise in enhancing utility of biomarkers to detect disease. OBJECTIVE: The present study sought to develop cognitive-biomarker profiles for detection of MCI. METHODS: Data were analyzed on 463 participants (normal control n = 378; MCI n = 85) from HABLE. Random forest analyses determined proteomic profile of MCI. Separate linear regression analyses determined variance accounted for by select biomarkers per neuropsychological measure. When neuropsychological measure with the least shared variance was identified, it was then combined with select biomarkers to create a biomarker-cognitive profile. RESULTS: The biomarker-cognitive profile was 90% accurate in detecting MCI. Among amnestic MCI cases, the detection accuracy of the biomarker-cognitive profile was 92% and increased to 94% with demographic variables. CONCLUSION: The biomarker-cognitive profile for MCI was highly accurate in its detection with use of only five biomarkers.

Chromosomal microarrays testing in children with developmental disabilities and congenital anomalies / Análise cromossômica por microarray em crianças com deficiências de desenvolvimento e anomalias congênitas

OBJECTIVES: Clinical use of microarray-based techniques for the analysis of many developmental disorders has emerged during the last decade. Thus, chromosomal microarray has been positioned as a first-tier test. This study reports the first experience in a Chilean cohort. METHODS: Chilean patients with developmental disabilities and congenital anomalies were studied with a high-density microarray (CytoScan(tm) HD Array, Affymetrix, Inc., Santa Clara, CA, USA). Patients had previous cytogenetic studies with either a normal result or a poorly characterized anomaly. RESULTS: This study tested 40 patients selected by two or more criteria, including: major congenital anomalies, facial dysmorphism, developmental delay, and intellectual disability. Copy number variants (CNVs) were found in 72.5% of patients, while a pathogenic CNV was found in 25% of patients and a CNV of uncertain clinical significance was found in 2.5% of patients. CONCLUSION: Chromosomal microarray analysis is a useful and powerful tool for diagnosis of developmental diseases, by allowing accurate diagnosis, improving the diagnosis rate, and discovering new etiologies. The higher cost is a limitation for widespread use in this setting. .

OBJETIVO: O uso clínico de técnicas baseadas em microarrays para a análise de transtornos de desenvolvimento tem surgido durante a última década. Assim, o microarray cromossômico tem sido posicionado como um teste de primeiro nível clínico. Relatamos a primeira experiência em uma coorte chilena. MÉTODOS: Pacientes chilenos com atraso de desenvolvimento e anomalias congênitas foram estudados com um microarray de alta densidade (CytoScan(tm) HD Array, Affymetrix, Inc., Santa Clara, CA, EUA). Pacientes tiveram estudos citogenéticos anteriores, ou um resultado normal ou de uma anomalia não bem caracterizada. RESULTADOS: Foram analisados 40 pacientes selecionados por dois ou mais critérios, incluindo: anomalias congênitas maiores, dismorfismo facial, atraso de desenvolvimento e deficiência intelectual. Uma variante do número de cópia (CNV) foi encontrada em 72,5% dos pacientes, enquanto que uma CNV patogênica foi encontrada em 25% dos pacientes e uma CNV de significado clínico incerto foi encontrada em 2,5% dos pacientes. CONCLUSÕES: A análise cromossômica microarray é uma ferramenta útil e poderosa em transtornos de desenvolvimento, permite um diagnóstico preciso, melhora a taxa de diagnóstico e descobre novas etiologias. O custo mais elevado é uma limitação para um uso difundido em nossa realidade. .

Estrogen levels modify scopolamine-induced amnesia in gonadally intact rats.

Previous studies suggested that estrogen plays a role in cognitive function by modulating the cholinergic transmission. However, most of the studies dealing with this subject have been conducted using ovariectomized rats. In the present study we evaluated the effects of physiological and supra-physiological variation of estrogen levels on scopolamine-induced amnesia in gonadally intact female rats. We used the plus-maze discriminative avoidance task (PMDAT) in order to evaluate anxiety levels and motor activity concomitantly to the memory performance. In experiment 1, female Wistar rats in each estrous cycle phase received scopolamine (1 mg/kg) or saline i.p. 20 min before the training session in the PMDAT. In experiment 2, rats in diestrus received estradiol valerate (1 mg/kg) or sesame oil i.m., and scopolamine (1 mg/kg) or saline i.p., 45 min and 20 min before the training, respectively. In experiment 3, rats in diestrus received scopolamine (1 mg/kg) or saline i.p. 20 min before the training, and estradiol valerate (1 mg/kg) or sesame oil i.m. immediately after the training session. In all experiments, a test session was performed 24 h later. The main results showed that: (1) scopolamine impaired retrieval and induced anxiolytic and hyperlocomotor effects in all experiments; (2) this cholinergic antagonist impaired acquisition only in animals in diestrus; (3) acute administration of estradiol valerate prevented the learning impairment induced by scopolamine and (4) interfered with memory consolidation process. The results suggest that endogenous variations in estrogen levels across the estrous cycle modulate some aspects of memory mediated by the cholinergic system. Indeed, specifically in diestrus, a stage with low estrogen levels, the impairment produced by scopolamine on the acquisition was counteracted by exogenous administration of the hormone, whereas the posttraining treatment potentiated the negative effects of scopolamine during the consolidation phase of memory.

MR imaging texture analysis of the corpus callosum and thalamus in amnestic mild cognitive impairment and mild Alzheimer disease.

BACKGROUND AND PURPOSE: TA is a branch of image processing that seeks to reduce image information by extracting texture descriptors from the image. TA of MR images of anatomic structures in mild AD and aMCI is not well-studied. Our objective was to attempt to find differences among patients with aMCI and mild AD and normal-aging subjects, by using TA applied to the MR images of the CC and the thalami of these groups of subjects. MATERIALS AND METHODS: TA was applied to the MR images of 17 patients with aMCI, 16 patients with mild AD, and 16 normal-aging subjects. The TA approach was based on the GLCM. MR images were T1-weighted and were obtained in the sagittal and axial planes. The CC and thalami were manually segmented for each subject, and 44 texture parameters were computed for each of these structures. RESULTS: TA parameters showed differences among the 3 groups for the CC and thalamus. A pair-wise comparison among groups showed differences for AD-control and aMCI-AD for the CC; and for AD-control, aMCI-AD, and aMCI-control for the thalamus. CONCLUSIONS: TA is a useful technique to aid in the detection of tissue alterations in MR images of mild AD and aMCI and has the potential to become a helpful tool in the diagnosis and understanding of these pathologies.

Chronic stress is associated with high cortisol levels and emotional coping mechanisms in amnestic mild cognitive impairment.

BACKGROUND/AIMS: To investigate the association between cortisol levels, chronic stress and coping in subjects with amnestic-type mild cognitive impairment (aMCI). METHODS: Cortisol levels were measured using morning saliva samples from 33 individuals with aMCI and from 41 healthy elderly. Chronic stress was evaluated with the Stress Symptoms List (SSL), whereas coping strategies were assessed using the Jalowiec Coping Scale. RESULTS: aMCI subjects with high SSL scores presented higher cortisol levels (p = 0.045). Furthermore, aMCI subjects who employed emotion-focused coping had higher SSL scores (p = 0.023). CONCLUSION: The association between increased cortisol secretion, chronic stress and coping strategies may be modulated by the presence or absence of cognitive impairment, where memory defi- cit awareness constitutes an additional potential factor involved in high stress severity.

Differences in grey and white matter atrophy in amnestic mild cognitive impairment and mild Alzheimer's disease.

BACKGROUND: Grey matter (GM) atrophy has been demonstrated in amnestic mild cognitive impairment (aMCI) and mild Alzheimer's disease (AD), but the role of white matter (WM) atrophy has not been well characterized. Despite these findings, the validity of aMCI concept as prodromal AD has been questioned. METHODS: We performed brain MRI with voxel-based morphometry analysis in 48 subjects, aiming to evaluate the patterns of GM and WM atrophy amongst mild AD, aMCI and age-matched normal controls. RESULTS: Amnestic mild cognitive impairment GM atrophy was similarly distributed but less intense than that of mild AD group, mainly in thalami and parahippocampal gyri. There were no difference between aMCI and controls concerning WM atrophy. In the mild AD group, we found WM atrophy in periventricular areas, corpus callosum and WM adjacent to associative cortices. DISCUSSION: We demonstrated that aMCI might be considered a valid concept to detect very early AD pathology, since we found a close proximity in the pattern of atrophy. Also, we showed the involvement of WM in mild AD, but not in aMCI, suggesting a combination of Wallerian degeneration and microvascular ischaemic disease as a plausible additional pathological mechanism for the discrimination between MCI and AD.

Autobiographical amnesia and accelerated forgetting in transient epileptic amnesia.

BACKGROUND: Recurrent brief isolated episodes of amnesia associated with epileptiform discharges on EEG recordings have been interpreted as a distinct entity termed transient epileptic amnesia (TEA). Patients with TEA often complain of autobiographical amnesia for recent and remote events, but show normal anterograde memory. OBJECTIVE: To investigate (a) accelerated long term forgetting and (b) autobiographical memory in a group of patients with TEA. METHODS: Seven patients with TEA and seven age matched controls were evaluated on a range of anterograde memory tasks in two sessions separated by 6 weeks and by the Galton-Crovitz test of cued autobiographical memory. RESULTS: Patients with TEA showed abnormal long term forgetting of verbal material, with virtually no recall after 6 weeks. In addition, there was impaired recall of autobiographical memories from the time periods 1985-89 and 1990-94 but not from 1995-1999. CONCLUSIONS: TEA is associated with accelerated loss of new information and impaired remote autobiographical memory. There are a number of possible explanations including ongoing subclinical ictal activity, medial temporal lobe damage as a result of seizure, or subtle ischaemic pathology. Future analyses should seek to clarify the relationship between aetiology, seizure frequency, and degree of memory impairment.

Frontal verbal amnesia. Phonological amnesia.

Although aphasic patients with frontal lobe damage may demonstrate impaired retention of verbal material, significant anterograde memory disturbances have not, to our knowledge, been reported with a minor Broca's aphasia. We describe a patient with minor Broca's aphasia who exhibited an unusual and profound anterograde memory disturbance, especially for phonologically specified stimuli. We suggest that this disturbance is attributable to an impairment in the volitional, controlled search of stored phonological information.

A síndrome de Wernicke e Korsakoff: uma compreensäo fisiodinâmica

A síndrome de Wernick e Korsakoff constitui um distúrbio cuja etiologia é uma nutricional, a nível da tiamina. Ela atinge principalmente indivíduos alcoólatras de longa data preferencialmente entre os 40 e 60 anos de idade. O quadro clínico da síndrome de Wernick é caracterizado por alteraçöes oculares, marcha atáxica e estado confusional. Na síndrome de Korsakoff registra-se a ocorryencia de alteraçöes da memória retrógrada e anterógrada e as vezes confabulaçöes. Na maior parte dos casos a síndrome de Wernicke parece constituir uma modalidade evolutivaprecedente a síndrome de Korsakoff. Os achado anátomo-patológicos demonstraram lesöes no núcleo hipotalâmico, tálamo, corpos mamilares, vérnix cerebelar superior e outras estruturas diencefálicas. As lesöes no núcleo vestibular expliicariam o nistagmo e a ataxia. Como seu prognóstico depende da precocidade do diagnóstico, é fundamental a sua determinaçäo em indivíduos considerados de risco para rápida introduçäo da terapêutica adequada