Migraine attacks, especially ones with aura, have symptoms similar to epileptic seizures, and the two may sometimes be difficult to differentiate clinically. However, the characteristic minute-by-minute symptom development and progress within 60 ‍min is useful for diagnosis. Although the details of its pathophysiology remain unsolved, cortical spreading depolarization (CSD) is one of the main pathogenetic factors. In epilepsy, clinical data have shown that ictal DC shifts could reflect impaired homeostasis of extracellular potassium by astrocyte dysfunction. Ictal DC shifts were found to be difficult to detect by scalp EEG, but can be clinically recorded from the seizure focus using wide-band EEG method. The similarity between DC shifts and CSD has been gaining attention from the neurophysiology point of view. The clinical implementation of infraslow activity/DC shifts analysis of scalp EEG is expected to elucidate further the pathophysiology of migraine, which may lie in the borderland of epilepsy.

Malfunction of the basal ganglia leads to movement disorders such as Parkinson’s disease, dystonia, Huntington’s disease, dyskinesia, and hemiballism, but their underlying pathophysiology is still subject to debate. To understand their pathophysiology in a unified manner, we propose the “dynamic activity model”, on the basis of alterations of cortically induced responses in individual nuclei of the basal ganglia. In the normal state, electric stimulation in the motor cortex, mimicking cortical activity during initiation of voluntary movements, evokes a triphasic response consisting of early excitation, inhibition, and late excitation in the output stations of the basal ganglia of monkeys, rodents, and humans. Among three components, cortically induced inhibition, which is mediated by the direct pathway, releases an appropriate movement at an appropriate time by disinhibiting thalamic and cortical activity, whereas early and late excitation, which is mediated by the hyperdirect and indirect pathways, resets on-going cortical activity and stops movements, respectively. Cortically induced triphasic response patterns are systematically altered in various movement disorder models and could well explain the pathophysiology of their motor symptoms. In monkey and mouse models of Parkinson’s disease, cortically induced inhibition is reduced and prevents the release of movements, resulting in akinesia/bradykinesia. On the other hand, in a mouse model of dystonia, cortically induced inhibition is enhanced and releases unintended movements, inducing involuntary muscle contractions. Moreover, after blocking the subthalamic nucleus activity in a monkey model of Parkinson’s disease, cortically induced inhibition is recovered and enables voluntary movements, explaining the underlying mechanism of stereotactic surgery to ameliorate parkinsonian motor signs. The “dynamic activity model” gives us a more comprehensive view of the pathophysiology underlying motor symptoms of movement disorders and clues for their novel therapies.

A 78-year-old man complained of subacute general fatigue and anorexia, following diplopia and gait disturbance. He demonstrated wide-based and small-stepped gait without objectively abnormal ocular movements. Brain ‍MRI showed enlargement of the pituitary stalk and gland with uniform contrast enhancement. PET-CT showed FDG ‍uptake in the pituitary gland, mediastinal lymph nodes, and left hilar lymph nodes. Blood investigations revealed panhypopituitarism and high serum IgG4 levels up to 265 ‍mg/dl. Histopathological examination revealed no IgG4-positive cell infiltration in the biopsied mediastinal lymph nodes. However, we suspected IgG4-associated hypophysitis based on the clinical symptoms and MRI findings, which were markedly resolved with steroid. Central masked diabetes insipidus was manifested, but was improved with oral desmopressin. We should pay close attention to the fact that IgG4-related hypophysitis may present with various symptoms regarded as indefinite complaints related to aging or underlying diseases, especially in elderly patients with multimorbidity.

A 44-year-old man was admitted due to a fever. He developed unconsciousness and respiratory failure, necessitating mechanical ventilation. After the administration of methylprednisolone and intravenous immunoglobulin for suspected autoimmune encephalitis, his consciousness and respiratory state improved. However, he exhibited pronounced tetraparalysis and impaired sensation below the neck. A spinal MRI revealed swelling of the entire spinal cord, indicating myelitis. Deep tendon reflexes were diminished in all extremities, and a nerve conduction study confirmed motor-dominant axonal polyneuropathy. Subsequently, he developed a fever and headache. Brain MRI demonstrated FLAIR hyperintensities in the basal ganglia and brain stem. CSF analysis for anti-glial fibrillary acidic protein (GFAP) antibody turned out positive, leading to the diagnosis of GFAP astrocytopathy. Although the steroid re-administration improved muscle strength in his upper limbs and reduced the range of diminished sensation, severe hemiparalysis remained. Severe GFAP astrocytopathy can be involved with polyneuropathy. Early detection and therapeutic intervention for this condition may lead to a better prognosis.

A 59-year-old man had developed visual abnormality, nausea, headache, and weight loss since three months before. The ophthalmologist found severe optic disc edema in both eyes, and referred him to our hospital. The patient had mild cerebellar ataxia. Increased cerebrospinal fluid pressure, increased protein and cell counts, positive oligoclonal band, and contrast-enhanced head MRI showed multiple linear perivascular radial gadolinium enhancement around bilateral lateral ventricles. His subjective and objective findings significantly improved with steroid treatment. The cerebrospinal fluid was found to be positive for glial fibrillary acidic protein (GFAP) antibodies, and a diagnosis of GFAP astrocytopathy was obtained. When optic edema or radial contrast effects was observed on contrast-enhanced MRI, GFAP astrocytopathy should be considerd. Prompt immunotherapy is required to circumvent the development of permanent visual impairment.

A 54-year-old man with a university degree was admitted to our hospital because of a two-year history of progressive dementia. He had familial sensorineural hearing loss and had been treated for epilepsy since his 30s. On admission, he showed severe dementia and parkinsonism without fever or skin rash. Systemic inflammation was evident, and the CSF cell count and IL-6 level were elevated to 53/μl and 307 ‍pg/ml, respectively. Brain MRI demonstrated diffuse brain atrophy. More detailed anamnesis revealed a history of rheumatoid arthritis in childhood and aseptic meningitis in his 20s. Genetic examination for autoinflammatory diseases demonstrated compound heterozygotic mutations in the NLRP3 gene, causing cryopyrin-associated periodic fever syndrome (CAPS). This case was atypical CAPS presenting as early-onset progressive dementia, without recurrent fever or urticaria-like eruption which are usually seen in this disease.

A 23-year-old man was admitted to our hospital with a one-year history of muscle weakness and atrophy. He had noticed contractures of the fingers of both hands from the age of 18. Examination revealed a skin rash including heliotrope rash and Gottron’s sign, joint contractures in the extremities, dysphagia, extensive muscle weakness and marked muscle atrophy. The serum creatine kinase level was 272 ‍IU/l and muscle biopsy showed typical perifascicular atrophy but little lymphocyte invasion. There was no interstitial pneumonia or malignancy, but muscle tendons showed elevated CT values suggesting calcification or fibrosis. Anti-nuclear matrix protein 2 (NXP-2) antibody-positive dermatomyositis was diagnosed on the basis of the serum antibody level. Methylprednisolone pulse therapy ameliorated the skin rash and bulbar palsy, but muscle weakness, atrophy and joint contractures were resistant to the treatment. There have been no previous reports of young adults with anti-NXP-2 antibody-positive dermatomyositis in whom joint contracture became evident as early as 4 years beforehand, which is a important feature for differential diagnosis of dermatomyositis.

A 62-year-old, right-handed man was diagnosed with asymptomatic bilateral chronic subdural hematomas and underwent hematoma removal on the left side only. At 1 month after surgery, he was admitted to our hospital because he began to have one or two attacks/day of apraxia of speech and dysesthesia of the right hand with a duration of approximately 5 ‍min. The left hematoma had not re-expanded, but fluid-attenuated inversion resonance imaging showed hyperintense lesions in the sulci adjacent to the hematoma. Moreover, single-photon emission computed tomography revealed low-uptake lesions in the left cerebrum adjacent to the hematoma. Electroencephalogram showed no abnormalities, and CT angiography showed a slight deviation of the left middle cerebral arteries due to the hematoma. The attacks disappeared within 10 days, although the volume of the hematoma was unchanged. It was suggested that his transient neurological deficits were caused by cerebral ischemia related to chronic subdural hematoma.