The patient was an 85-year-old man with a one-year history of difficulty reading kana. Neuropsychological evaluation revealed kana (phonogram)-selective reading impairment and kanji (ideogram)-dominant writing impairment. MRI revealed significant cerebral atrophy in the left occipital cortex, leading to the clinical diagnosis of posterior cortical atrophy (PCA). Cerebrospinal fluid amyloid β_1-42 levels were reduced, and amyloid PET showed accumulation in the posterior cingulate cortex, precuneus, and frontal lobe. In contrast, tau PET showed no accumulation in the atrophied brain areas. Episodes of REM sleep behavior disorder and decreased uptake on meta-iodobenzylguanidine (MIBG) myocardial scintigraphy suggested the involvement of Lewy body pathology. PCA with distinct laterality has been rarely reported, and ‍this is the first case to present Kana-selective reading impairment and Kanji-dominant writing impairment with neurodegenerative background.

The insula is often referred to as “the fifth lobe” of the brain, and its accessibility used to be very limited due to the deep location under the opercula as well as the sylvian vasculature. It was not until the availability of modern stereo-electroencephalography (SEEG) technique that the intracranial electrodes could be safely and chronically implanted within the insula, thereby enabling anatomo-electro-clinical correlations in seizures of this deep origin. Since the first report of SEEG-recorded insular seizures in late 1990s, the knowledge of insular lobe epilepsy (ILE) has rapidly expanded. Being on the frontline for the diagnosis and management of epilepsy, neurologists should have a precise understanding of ILE to differentiate it from epilepsies of other lobes or non-epileptic conditions. Owing to the multimodal nature and rich anatomo-functional connections of the insula, ILE has a wide range of clinical presentations. The following symptoms should heighten the suspicion of ILE: somatosensory symptoms involving a large/bilateral cutaneous territory or taking on thermal/painful character, and cervico-laryngeal discomfort. The latter ranges from slight dyspnea to a strong sensation of strangulation (laryngeal constriction). Other symptoms include epigastric discomfort/nausea, hypersalivation, auditory, vestibular, gustatory, and aphasic symptoms. However, most of these insulo-opercular symptoms can easily be masked by those of extra-insular seizure propagation. Indeed, sleep-related hyperkinetic (hypermotor) epilepsy (SHE) is a common clinical presentation of ILE, which shows predominant hyperkinetic and/or tonic-dystonic features that are often indistinguishable from those of fronto-mesial seizures. Subtle objective signs, such as constrictive throat noise (i.e., laryngeal constriction) or aversive behavior (e.g., facial grimacing suggesting pain), are often the sole clue in diagnosing insular SHE. Insular-origin seizures should also be considered in temporal-like seizures without frank anatomo-electro-clinical correlations. All in all, ILE is not the epilepsy of an isolated island but rather of a crucial hub involved in the multifaceted roles of the brain.

Identification of insular lobe epilepsy (ILE) presents a major clinical challenge in the diagnosis and treatment of drug-resistant focal epilepsies. ILE has diverse clinical presentations due to the multifaceted functions of the insula. Surface EEG findings do not provide straightforward information to predict this deeply-situated origin of seizures; they are even misleading, masquerading as those of other focal epilepsies, such as temporal and frontal ones. Non-invasive imagings may disclose insular abnormalities, but extra-insular abnormalities can coexist or even stand out. Careful reading and a second-look guided by other clinical information are crucial in order not to miss subtle insulo-opercular abnormalities. Furthermore, a possible insular origin of seizures should be considered in MRI-negative frontal/temporal/parietal epilepsies. Therefore, exploration/exclusion of insular-origin seizures is necessary for a great majority of surgical candidates. As for the stereo-electroencephalography, considered as the gold standard method for intra-cranial EEG investigations with suspicion of ILE, planning of electrode positions/trajectories require sufficient knowledge of the functional localization and anatomo-functional connectivity of the insula. Dense sampling within the insula is required in patients with probable ILE, because the seizure-onset zone can be restricted to a single insular gyrus or even a part of it. It is also crucial to explore extra-insular regions on the basis of non-invasive investigation results while considering their anatomo-functional relationships with the insula. From a surgical perspective, differentiating seizures strictly confined to the insula from those extending to the opercula is of particular importance. Pure insular seizures can be treated with less invasive measures, such as radiofrequency thermocoagulation. To conclude, close attention must be paid to the possibility of ILE throughout the diagnostic workup. The precise identification/exclusion of ILE is a prerequisite to provide appropriate and effective surgical treatment in pharmaco-resistant focal epilepsies.

Neuromyelitis optica spectrum disorders (NMOSD) is one of autoimmune inflammatory diseases and is characterized by area postrema syndrome, brainstem syndrome, optic neuritis, and/or myelitis. Typical myelitis is longitudinally extended transverse myelitis (LETM) which extends over three vertebral bodies. Several previous case reports have suggested association between cancer and NMOSD. A 50-year-old woman had breast cancer and underwent mastectomy and, 10 months later, she had developed acutely progressive dysbasia. Spine MRI showed LETM in 13 vertebrae length and blood test revealed positive anti-aquaporin 4 (anti-AQP4) antibody based on enzyme-linked immunosorbent assay with index of over 40. She was treated by intravenous methylprednisolone, plasma exchange, and intravenous immunoglobulin, followed by oral prednisolone. The condition had mostly recovered after the treatment. A small population of NMOSD has the aspect of paraneoplastic neurological syndrome. The age of onset in patients with cancer-associated NMOSD tends to be higher than that in individuals with NMOSD due to any causes of NMOSD.

A 78-year-old man was admitted to the hospital with a 4-day history of fever and confusion. Physical examination revealed oral dryness and decreased skin turgor. Blood tests showed hyponatremia (121.5 ‍mEq/l), and cerebrospinal fluid examination revealed positivity for herpes simplex virus 1 (HSV-1) via polymerase chain reaction. He was diagnosed with herpes simplex encephalitis and initiated acyclovir treatment. The hyponatremia was diagnosed as cerebral salt wasting syndrome (CSWS) and treated with hypertonic saline infusion and fludrocortisone. The cerebrospinal fluid HSV-1 DNA became negative, and the serum sodium levels normalized. Hyponatremia complicated with encephalitis is often caused by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), whereas CSWS is rare, mostly observed in tuberculous meningitis. Differentiating between the SIADH and CSWS is important as they require distinct therapeutic strategies.

We describe a 44-year-old man with a complaint of atonic seizures of the left upper limb, followed by generalized seizures. Brain MRI showed isolated juxtacortical white matter T₂ hyperintensity with gadolinium (Gd) enhancement of the adjacent cortical gray matter and subcortical white matter in the right frontal convexity. Treatment with levetiracetam was effective for seizure suppression, and he had no other neurological abnormalities. Human leukocyte antigen typing revealed B54 and Cw1, which indicated the possibility of neuro-Sweet disease. However, a general examination, which included vital signs and eye and skin findings, was normal. A cerebrospinal fluid test showed a mild elevation in protein levels without pleocytosis and a normal range of interleukin-6. Electroencephalography showed intermittent slow waves without epileptic discharge in the bilateral temporal lobes. We detected subtle flow voids in the pia mater of the left frontal lobe, which suggested cerebrovascular disease, and specifically, the possibility of dural arteriovenous fistulas. Computed tomography angiography showed abnormally dilated perimedullary veins in the left frontal lobe. Cerebral angiography confirmed the existence of four dural arteriovenous fistulas, which included two retrograde leptomeningeal venous drainages in the right frontal cortical veins supplied by the anterior branch of the right middle meningeal artery. The other dural arteriovenous fistulas were retrograde leptomeningeal venous drainages in the left frontal cortical veins supplied by the anterior and posterior convexity branches of the left middle meningeal artery. The patient underwent successful endovascular embolization of all dural arteriovenous fistulas with Onyx injection. A follow-up MRI showed gradual improvement of the T₂ hyperintensity and Gd enhancement. He remained seizure-free for 2 years following endovascular embolization.

The patient, a 36-year-old female, had no previous history of shingles. She was admitted to the hospital due to nausea and lightheadedness. Upon admission, she was diagnosed with bilateral medial medullary infarcts. She received treatment with intravenous edaravone and argatroban, as well as antiplatelet therapy with aspirin and clopidogrel. However, her dysphagia, dysarthria, and paraplegia worsened. Due to changes in the lesion of the basilar artery on brain ‍MRA, we suspected the possibility of basilar artery dissection, and discontinued antiplatelet therapy. Subsequent imaging studies suggested vasculitis. After examining the cerebrospinal fluid, we diagnosed varicella-zoster virus (VZV) vasculopathy. Based on this diagnosis, we administered steroid pulse therapy for three days, started intravenous acyclovir, and resumed antithrombotic therapy with clopidogrel. Prednisone was administered for five days. Biochemical tests revealed an elevated D-dimer level. Due to the presence of lower extremity venous thrombus, clopidogrel was replaced with apixaban. The acyclovir infusion was discontinued due to observed acyclovir-induced neutropenia. These treatments improved neurological symptoms, circumflex thickening of the basilar artery, and contrast effects in the same area. On the 70th day, the patient was transferred to the hospital for rehabilitation. It is important to consider VZV angiopathy as a potential cause of juvenile cerebral infarction accompanying progressive basilar artery stenosis, regardless of the presence or absence of a skin rash.

Age-specific characteristics and annual changes of social maturity in adults with Down syndrome (DS) were retrospectively investigated. Forty-six individuals aged 15–58 years were enrolled. Social age (SA) in all domains and subdomains was assessed using the revised S-M social maturity test. Thirty-four cases were evaluated for SA changes over time at 1 year. The SA of adult DS tended to be lower in those under 20 and over 42 years of age. The SA of adults with DS was lowest in the Socialization domain, and this trend was generally common across all age groups. The annual decline of SA was more prominent in the DS-AD group than in the non-DS-AD group. Annual decline of SA in the communication domain had the same discriminative power as that in the whole domains in the discrimination of DS-AD from non-DS-AD. These results are expected to contribute to the development of clinical diagnostic methods for DS-AD in the future.

We report two patients with autoimmune cerebellar ataxia who fulfilled the diagnostic criteria of multiple system atrophy (MSA) and responded to immunotherapies. Patient 1 was a 72-year-old man who was diagnosed with clinically probable MSA according to Movement Disorder Society criteria. Patient 2 was a 68-year-old man who was diagnosed with clinically established MSA according to Movement Disorder Society criteria. Both patients showed cerebellar ataxia, autonomic dysfunction, and pyramidal tract signs; however, they also had atypical clinical features. Patient 1 exhibited self-‍limiting mild improvement of clinical symptoms and had inflammatory findings in his cerebrospinal fluid. Patient 2 showed a rapidly progressive clinical course. We therefore examined anti-neuronal antibodies using tissue-based immunohistochemical assays with frozen rat cerebellum sections. We detected autoantibodies that mainly reacted with the cytoplasm of Purkinje cells. The two patients then underwent immunotherapies, which led to substantial improvements in their clinical symptoms. Our findings indicate that some patients with autoimmune cerebella ataxia have clinical features that resemble MSA, and respond well to immunotherapies.