Inhibitory synapse loss and accumulation of amyloid beta in inhibitory presynaptic terminals in Alzheimer's disease.

BACKGROUND AND PURPOSE: Synapse degeneration in Alzheimer's disease (AD) correlates strongly with cognitive decline. There is well-established excitatory synapse loss in AD with known contributions of pathological amyloid beta (Aß) to excitatory synapse dysfunction and loss. Despite clear changes in circuit excitability in AD and model systems, relatively little is known about pathology in inhibitory synapses. METHODS: Here human postmortem brain samples (n = 5 control, 10 AD cases) from temporal and occipital cortices were examined to investigate whether inhibitory synapses and neurons are lost in AD and whether Aß may contribute to inhibitory synapse degeneration. Inhibitory neurons were counted in all six cortical layers using stereology software, and array tomography was used to examine synapse density and the accumulation of Aß in synaptic terminals. RESULTS: Differing inhibitory neuron densities were observed in the different cortical layers. The highest inhibitory neuron density was observed in layer 4 in both brain regions and the visual cortex had a higher inhibitory neuron density than the temporal cortex. There was significantly lower inhibitory neuron density in AD than in control cases in all six cortical layers. High-resolution array tomography imaging revealed plaque-associated loss of inhibitory synapses and accumulation of Aß in a small subset of inhibitory presynaptic terminals with the most accumulation near amyloid plaques. CONCLUSIONS: Inhibitory neuron and synapse loss in AD may contribute to disrupted excitatory/inhibitory balance and cognitive decline. Future work is warranted to determine whether targeting inhibitory synapse loss could be a useful therapeutic strategy.

Cerebral Venous Sinus Thrombosis as a Rare Complication of Systemic Lupus Erythematosus: Subgroup Analysis of the VENOST Study.

AIM: Systemic lupus erythematosus (SLE) is an unusual risk factor for cerebral venous sinus thrombosis (CVST). As few CVST patients with SLE have been reported, little is known regarding its frequency as an underlying etiology, clinical characteristics, or long-term outcome. We evaluated a large cohort of CVST patients with SLE in a multicenter study of cerebral venous thrombosis, the VENOST study, and their clinical characteristics. MATERIAL AND METHOD: Among the 1144 CVST patients in the VENOST cohort, patients diagnosed with SLE were studied. Their demographic and clinical characteristics, etiological risk factors, venous involvement status, and outcomes were recorded. RESULTS: In total, 15 (1.31%) of 1144 CVST patients had SLE. The mean age of these patients was 39.9 ± 12.1 years and 13 (86.7%) were female. Presenting symptoms included headache (73.3%), visual field defects (40.0%), and altered consciousness (26.7%). The main sinuses involved were the transverse (60.0%), sagittal (40.0%), and sigmoid (20.0%) sinuses. Parenchymal involvement was not seen in 73.3% of the patients. On the modified Rankin scale, 92.9% of the patients scored 0-1 at the 1-month follow-up and 90.9% scored 0-1 at the 1-year follow-up. CONCLUSIONS: SLE was found in 1.31% of the CVST patients, most frequently in young women. Headache was the most common symptom and the CVST onset was chronic in the majority of cases. The patient outcomes were favorable. CVST should be suspected in SLE patients, even in those with isolated chronic headache symptoms with or without other neurological findings.

Panayiotopoulos syndrome and symptomatic occipital lobe epilepsy of childhood: a clinical and EEG study.

AIM: Panayiotopoulos syndrome (PS) is an age-related seizure susceptibility syndrome that affects the central autonomic system. Although the majority of the few ictal recordings obtained so far suggest an occipital origin, semiological and interictal EEG data appear to favour more extensive involvement. In this study, the characteristics (including those based on semiology and EEG) of children with Panayiotopoulos syndrome (n=24) and those with lesion-related, symptomatic occipital lobe epilepsy (SOLE) (n=23) were compared. METHODS: Detailed semiological information and EEG parameters including the localisation, distribution, density (n/sec), reactivity, and morphological characteristics of spike-wave foci and their relationship with different states of vigilance were compared between the two groups. RESULTS: The age at seizure onset was significantly younger in patients with symptomatic occipital lobe epilepsy than in those with PS (mean age at onset: 3.4 versus 5.6 years, respectively; p=0.044). Autonomic seizures (p=0.001) and ictal syncope (p=0.055) were more frequent in PS than in symptomatic occipital lobe epilepsy (87.5% and 37.5% versus 43.5% and 13%, respectively). The interictal spike-wave activity increased significantly during non-rapid eye movement (non-REM) sleep in both groups. The spike waves in non-REM seen in PS tended to spread mainly to central and centro-temporal regions. CONCLUSIONS: The results indicate that although common features do exist, Panayiotopoulos syndrome differs from symptomatic occipital lobe epilepsy and has a unique low epileptogenic threshold related to particular brain circuits.

Characterisation of RT-QuIC negative cases from the UK National CJD Research and Surveillance programme.

INTRODUCTION: Incorporation of the real-time quaking-induced conversion (RT-QuIC) assays for diagnosis of sporadic Creutzfeldt-Jakob disease (CJD) has transformed diagnosis largely related to its extremely high specificity. However, the test has a c.10% false-negative result and we aim to characterize the clinical features, investigation profile, and molecular subtype in this cohort of patients. METHODS: 250 individuals diagnosed with definite sporadic CJD were identified from the UK National CJD Research and Surveillance Unit from 2012 to 2023. We compared the clinical features and investigation profile in those with a negative CSF RT-QuIC to those with a positive RT-QuIC. RESULTS: 27 individuals (10.8%) were CSF RT-QuIC negative. Median age of onset was younger (62 years vs 68 years, p = 0.002), median disease duration was longer (4.4 months vs 10.5 months, p < 0.001), and these individuals were less likely to present with gait difficulties (73% vs 93%, p = 0.003) or motor symptoms (62% vs 80%, p = 0.04). The sensitivity of electroencephalography and diffusion-weighted MRI were similar in both groups. In those who were RT-QuIC negative, there was an overrepresentation of the VV1 (32% vs 1%) and MM2 molecular subtypes (21% vs 3%). Co-occurring neurodegenerative disease was found in 33% (9/27) of those who were RT-QuIC negative. CONCLUSIONS: Individuals with sporadic CJD and a negative CSF RT-QuIC present with younger age of onset, different clinical features and are over-represented with the VV1 and MM2 subtypes of sporadic CJD. Further work is required to better understand the biochemical properties contributing to RT-QuIC negative results in these cases.

Headache as the sole presenting symptom of cerebral venous sinuses thrombosis: Subgroup analysis of data from the VENOST study.

OBJECTIVES: Headache is the most common complaint in cerebral venous sinus thrombosis (CVST) and it may sometimes be the only symptom in these patients. This retrospective and prospective study was an investigation of any differences in terms of clinical risk factors, radiological findings, or prognosis in patients with CVST who presented with isolated headache (IH) and cases with other concomitant findings (non-isolated headache [NIH]). METHODS: A total of 1144 patients from a multicenter study of cerebral venous sinus thrombosis (VENOST study) were enrolled in this research. The demographic, biochemical, clinical, and radiological aspects of 287 IH cases and 857 NIH cases were compared. RESULTS: There were twice as many women as men in the study group. In the IH group, when gender distribution was evaluated by age group, no statistically significant difference was found. The onset of headache was frequently subacute and chronic in the IH group, but an acute onset was more common in the NIH group. Other neurological findings were observed in 29% of the IH group during follow-up. A previous history of deep, cerebral, or other venous thromboembolism was less common in the IH group than in the NIH group. Transverse sinus involvement was greater in the IH group, whereas sagittal sinus involvement was greater in the NIH group. The presence of a plasminogen activator inhibitor (PAI) mutation was significantly greater in the IH group. CONCLUSION: IH and CVST should be kept in mind if a patient has subacute or chronic headache. PAI, which has an important role in thrombolytic events, may be a risk factor in CVST. Detailed hematological investigations should be considered. Additional studies are needed.

Co-existence of multiple sclerosis and anti-NMDA receptor encephalitis: A case report and review of literature.

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a serious autoimmune disorder characterized by psychiatric symptoms, seizures and movement disorder. Predisposing factors have been reported since the time it was described, and its pathophysiology has been tried to be clarified over the years. Although overlap with other demyelinating diseases had been reported, such an association between Multiple Sclerosis (MS) anti ANTI-NMDAR encephalitis is limited to only a few case reports. In this article, a patient diagnosed with relapsing remitting multiple sclerosis (RRMS) for ten years who then developed NMDA-R encephalitis while on disease modifying treatment will be presented and possible common pathophysiology with previously reported literature will be discussed.

Epileptic seizures in cerebral venous sinus thrombosis: Subgroup analysis of VENOST study.

PURPOSE: The aim of this study is to evaluate the presence and prognostic impact of early seizures in cerebral venous sinus thrombosis patients (CVST). METHOD: VENOST is a retrospective and prospective national multicenter observational study. CVST patients with or without epileptic seizures (ES) were analyzed and compared in terms of demographic and imaging data, causative factors, clinical variables, and prognosis in a total of 1126 patients. RESULTS: The mean age of the patients in the ES group was 39.73 ± 12.64 and 40.17 ± 14.02 years in the non-ES group (p > 0.05). Epileptic seizures were more common (76.6 %) in females (p < 0.001). Early ES occurred in 269 of 1126 patients (23.9 %). Epileptic seizures mainly presented in the acute phase (71.4 %) of the disease (p < 0.001). Majority of these (60.5 %) were in the first 24 h of the CVST. The most common neurological signs were focal neurologic deficits (29.9 %) and altered consciousness (31.4 %) in the ES group. Superior sagittal sinus (SSS) and cortical veins (CV) involvement were the most common sites of thrombosis and the mostly related etiology were found puerperium in seizure group (30.3 % vs 13.9 %). Patients with seizures had worse outcome in the first month of the disease (p < 0.001) but these did not have any influence thereafter. CONCLUSIONS: In this largest CVST cohort (VENOST) reported female sex, presence of focal neurological deficits and altered consciousness, thrombosis of the SSS and CVs, hemorrhagic infarction were risk factors for ES occurrence in patients with CVST.

A case of perioral myoclonia with absences and its evolution in adulthood?

The rare syndrome of perioral myoclonia with absences (POMA) is described as a specific type of idiopathic generalized epilepsy in which absence seizures are accompanied by prominent perioral myoclonus as a consistent symptom. We present a 52-year-old man who was referred to our department due to treatment-resistant epilepsy. Typical seizures were described as rhythmic twitching of the lips which started at six years old, and his first convulsive seizure occurred at around 20 years old. Based on video-EEG recordings, we present two distinct EEG patterns accompanied by slight differences in clinical manifestations, which appear to be atypical of POMA. Firstly, consciousness was preserved during seizures, with no manifestation of absences. Secondly, regarding the EEG features, in some of the seizures, the perioral motor symptoms were tonic rather than myoclonic. The defining features of POMA are discussed in relation to this case.

Increased photosensitivity following short sleep in sleep deprived patients.

INTRODUCTION: We aimed to determine the effect of short day-time sleep on photoparoxysmal epileptic activity in sleep-deprived patients. METHODS: We retrospectively reviewed video-EEG recordings performed between 2003 and 2015. All recordings following at least four hours of sleep deprivation, including intermittent photic stimulation (IPS) both before and after sleep with any form of epileptiform activity were included. The study group was divided into four subgroups: (1) no photoparoxysmal response (PPR) group, with epileptiform activities other than PPRs; (2) increment group, with PPR duration increased by ≥200% after vs. before sleep; (3) no significant change group, with PPR duration increased between 50% and 200% after vs. before sleep; (4) decrement group, with PPR duration increased ≤50% after vs. before sleep. RESULTS: A total number of 5805 EEG recordings from 459 patients was analyzed. Photosensitivity was present in 98 patients (21.4%). The PPRs after sleep were increased in 70% of the photosensitive patients, did not change in 23%, and were decreased in 7%. The increase in duration of PPRs was statistically significant (P<0.001). In our cohort, photosensitivity would have been detected in 67 patients if IPS was applied only before sleep and in 91 patients if IPS was applied only after awakening (P<0.05). CONCLUSIONS: This study demonstrates that photosensitivity is enhanced after awakening from a short sleep following sleep deprivation. Thus, we recommend performing IPS after awakening to increase sensitivity to detect photoparoxysmal epileptiform discharges.