Brain reserve contributes to distinguishing preclinical Alzheimer's stages 1 and 2.

BACKGROUND: In preclinical Alzheimer's disease, it is unclear why some individuals with amyloid pathologic change are asymptomatic (stage 1), whereas others experience subjective cognitive decline (SCD, stage 2). Here, we examined the association of stage 1 vs. stage 2 with structural brain reserve in memory-related brain regions. METHODS: We tested whether the volumes of hippocampal subfields and parahippocampal regions were larger in individuals at stage 1 compared to asymptomatic amyloid-negative older adults (healthy controls, HCs). We also tested whether individuals with stage 2 would show the opposite pattern, namely smaller brain volumes than in amyloid-negative individuals with SCD. Participants with cerebrospinal fluid (CSF) biomarker data and bilateral volumetric MRI data from the observational, multi-centric DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE) study were included. The sample comprised 95 amyloid-negative and 26 amyloid-positive asymptomatic participants as well as 104 amyloid-negative and 47 amyloid-positive individuals with SCD. Volumes were based on high-resolution T2-weighted images and automatic segmentation with manual correction according to a recently established high-resolution segmentation protocol. RESULTS: In asymptomatic individuals, brain volumes of hippocampal subfields and of the parahippocampal cortex were numerically larger in stage 1 compared to HCs, whereas the opposite was the case in individuals with SCD. MANOVAs with volumes as dependent data and age, sex, years of education, and DELCODE site as covariates showed a significant interaction between diagnosis (asymptomatic versus SCD) and amyloid status (Aß42/40 negative versus positive) for hippocampal subfields. Post hoc paired comparisons taking into account the same covariates showed that dentate gyrus and CA1 volumes in SCD were significantly smaller in amyloid-positive than negative individuals. In contrast, CA1 volumes were significantly (p = 0.014) larger in stage 1 compared with HCs. CONCLUSIONS: These data indicate that HCs and stages 1 and 2 do not correspond to linear brain volume reduction. Instead, stage 1 is associated with larger than expected volumes of hippocampal subfields in the face of amyloid pathology. This indicates a brain reserve mechanism in stage 1 that enables individuals with amyloid pathologic change to be cognitively normal and asymptomatic without subjective cognitive decline.

A study of the relationship between serum uric acid levels and pain in patients with migraine.

Serum uric acid (SUA), the end product of purine metabolism acts as an antioxidant and is related to oxidative stress. It has been reported that SUA may be involved in the pathogenesis of neurodegenerative diseases including Alzheimer disease, Huntington disease, Parkinson disease, and multiple sclerosis. However, studies evaluating SUA levels in migraine are scarce. This study aimed to explore the relationship between pain characteristics and SUA levels in patients with migraine and compare SUA levels in migraine patients during a headache attack and headache-free period with those control groups. This prospective, cross-sectional study included 78 patients with migraine and 78 healthy subjects who were randomly selected from hospital personnel as the control group. Headache characteristics (duration of attack, pain intensity, and headache frequency) and sociodemographic features were recorded. The SUA level was measured once in the control group and twice in the migraine patients, during the migraine attack and headache-free periods. Although the SUA levels of the migraine group in the headache-free period were higher than those of the control group, the difference was not statistically significant. Gender was not significantly related to the change in SUA levels between the attack and headache-free period. When the correlation between age, duration of migraine, frequency, duration, and intensity of pain was evaluated; the difference between SUA levels in female migraine patients was weakly correlated with headache intensity, whereas male patients had a moderate correlation. ( P < .05; R > 0.250, and R > 0.516, respectively). The difference in SUA level in the migraine attack period compared to the headache-free period showing a positive correlation with pain intensity suggested that SUA may have a role in migraine due to its antioxidant role.

Autoimmune encephalitis and paraneoplastic syndromes in Turkey: a multi-centre study.

BACKGROUND: Autoimmune encephalitis (AIE) and paraneoplastic syndromes (PNS) are both rare groups of neurological diseases that are difficult to diagnose. AIM: We aimed to determine the common and distinct aspects of these two aetiologies of encephalitis as well as the characteristics of our patient group. METHODS: We respectively analysed the records of the patients including symptoms, demographic features, neurological examination, cranial-magnetic-resonance-imaging (MRI), electroencephalography (EEG) findings, cerebrospinal fluid results (CSF) findings. Autoimmune/paraneoplastic autoantibodies in blood and/or CSF were all documented. RESULTS: Forty-six patients fulfilled the diagnostic criteria. Thirty-eight of them were diagnosed with AIE, and 8 of them were diagnosed with PNS. The PNS group had higher nonconvulsive status epilepticus than the AIE (2/8 vs 0/38; p=0.027). PNS patients were diagnosed with a malignancy in their follow-ups more than those in the AIE group [4/38 vs 8/8] (p<0.001). When the symptoms of antibody-positive and negative patients were compared in the AIE group, the rates of consciousness/memory problems (13/15 vs 11/23; p=0.020) and speech impairment (8/15 vs 2/23; p=0.004) were significantly higher in patients without antibodies (n: 15) than in antibody-positive patients (n: 23). In antibody-negative groups, the rates of memory problems in neurological examination (13/15 vs 12/23 p=0.028) and temporal findings on electroencephalography were more prominent than antibody-positive groups (1/23 vs 5/15; p=0.027). The number of patients with cerebellar signs was higher in antibody-positive patients (6/23 vs 0/15; p=0.038). CONCLUSION: Although the positivity of autoantibodies is critical in the diagnosis of AIE and PNS, even minor differences in clinical and laboratory findings of patients are helpful in the diagnosis, especially in the autoantibody-negative patients. Comparing the data with other population studies has shown that several inherited and environmental factors may contribute to the pathophysiology of AIE and PNS, as well as clinical and laboratory differences.

The Significance and Reliability of Imaging Findings in Pseudotumor Cerebri.

The objective of our study was to provide a comparative assessment of previously reported magnetic resonance imaging (MRI) parameters in primary and secondary pseudotumor cerebri (PTC) patients, to examine their diagnostic contribution, and to evaluate their association with symptoms, neuro-ophthalmological findings, laboratory results, and cerebrospinal fluid characteristics. Twenty-eight consecutive patients with PTC were included in the study. Age- and sex-matched 20 individuals with normal neurologic examination served as the control group. Modified Dandy Criteria were used for the diagnosis of PTC. Orbital and cranial MRI and MR venography of all patients and controls were assessed by three radiologists. According to our study, posterior flattening of the globe (64% sensitive, 100% specific), optic nerve sheath distention (46% sensitive, 100% specific), vertical tortuosity of the optic nerve (30% sensitive, 95% specific), and partial empty sella (43% sensitive, 100% specific) emerged as particularly valuable markers for a diagnosis of PTC.