Motor Progression and Nigrostriatal Neurodegeneration in Parkinson Disease.

OBJECTIVE: The motor severity in Parkinson disease (PD) is believed to parallel dopaminergic terminal degeneration in the striatum, although the terminal was reported to be virtually absent by 4 years postdiagnosis. Meanwhile, neuromelanin-laden dopamine neuron loss in the substantia nigra (SN) elucidated a variability at early stages and gradual loss with less variability 10 years postdiagnosis. Here, we aimed to clarify the correlation between motor impairments and striatal dopaminergic terminal degeneration and nigral neuromelanin-laden dopamine neuron loss at early to advanced stages of PD. METHODS: Ninety-three PD patients were divided into early and advanced subgroups based on motor symptom duration and whether motor fluctuation was present. Striatal dopaminergic terminal degeneration was evaluated using a presynaptic dopamine transporter tracer, 123 I-ioflupane single photon emission computed tomography (SPECT). Nigral neuromelanin-laden dopamine neuron density was assessed by neuromelanin-sensitive magnetic resonance imaging (NM-MRI). RESULTS: In patients with early stage PD (motor symptoms for ≤8 or 10 years), motor dysfunction during the drug-off state was paralleled by a decline in 123 I-ioflupane uptake in the striatum despite the absence of a correlation with reductions in NM-MRI signals in SN. Meanwhile, in patients with advanced stage PD (motor symptoms for >8 or 10 years and with fluctuation), the degree of motor deficits during the drug-off state was not correlated with 123 I-ioflupane uptake in the striatum, despite its significant negative correlation with NM-MRI signals in SN. INTERPRETATION: We propose striatal dopaminergic terminal loss measured using 123 I-ioflupane SPECT and nigral dopamine neuron loss assessed with NM-MRI as early stage and advanced stage motor impairment biomarkers, respectively. ANN NEUROL 2022;92:110-121.

[Posterior Subthalamic Area, Pallidothalamic Tract, and Pedunculopontine Nucleus:Deep Brain Stimulation Targets for Parkinson's Disease and Essential Tremor].

This article reviews the stereotactic targets in the posterior subthalamic area(PSA), fields H1/H2 of Forel(pallidothalamic tract), and the pedunculopontine nucleus(PPN)to complement the preceding articles on stereotactic and functional neurosurgery for movement disorders in the present issue of No Shinkei Geka. Two regions within the subthalamus, the PSA and fields H1/H2 of Forel, are the revisited stereotactic targets to treat movement disorders. Currently, the PSA is often utilized to treat essential tremor and various types of tremor. Fields H1/H2 of Forel are investigated as a target for magnetic resonance-guided focused ultrasound to treat motor symptoms and motor complications in patients with Parkinson's disease. For the past twenty years, the PPN has been investigated to treat refractory gait freezing and fall in patients with Parkinson's disease. These revisited and novel targets may be utilized as substitutes and complements for the present standard stereotactic targets.

Thalamic Deep Brain Stimulation for Refractory Atypical Tremor after Encephalitis of Unknown Etiology: A Case Report.

Tremor associated with encephalitis is usually transient and rarely becomes chronic and refractory. Treatment for such tremor using deep brain stimulation (DBS) has not yet been reported. We report an uncommon case of chronic tremor after encephalitis of unknown etiology and its outcome treated with thalamic DBS. A 47-year-old man presented with a 6-month history of medically refractory tremor after non-infectious and probable autoimmune encephalitis. The patient showed an atypical mixture of resting, postural, kinetic, and intention tremor. The tremor significantly disabled the patient's activities of daily life (ADL). The patient underwent bilateral thalamic DBS surgery. DBS leads were placed to cross the border between the ventralis oralis posterior (Vop) nucleus and ventralis intermedius (Vim) nucleus of the thalamus. Stimulation of both the Vop and Vim using the bipolar contacts controlled the mixed occurrence of tremor. The ADL and performance scores on The Essential Tremor Rating Assessment Scale (TETRAS) improved from 47 to 0 and from 44 to 9, respectively. The therapeutic effects have lasted for 24 months. Administration of combined Vop and Vim DBS may control uncommon tremor of atypical etiology and phenomenology.

Treatment-resistant neuromyelitis optica spectrum disorders associated with Toxocara canis infection: A case report.

A 53-year-old woman was admitted to the department of neurology in Tenri Hospital because of progressive thoracic myelitis a month after she had eaten uncooked bovine liver. A previous episode of right optic neuritis and a positive test for serum anti-aquaporin-4 antibodies indicated a diagnosis of neuromyelitis optica spectrum disorders. Although the patient initially recovered with the reduction of anti-aquaporin-4 antibodies during treatment with intravenous methylprednisolone infusion and plasma exchange, her neurological symptoms deteriorated soon after the completion of plasma exchange. Western blotting analysis detected anti-Toxocara canis antibodies in the serum; thus, the patient underwent oral albendazole treatment. This resulted in the alleviation of her symptoms. We therefore consider that rigorous investigation should be encouraged to detect rare pathogens including parasites in cases of treatment-resistant neuromyelitis optica spectrum disorders.

[Lymphocytic primary angiitis of the central nervous system with fan-shaped linear enhancement converging to the lateral ventricles: a case report].

We report a case of lymphocytic primary angiitis of the central nervous system (PACNS) with a characteristic gadolinium-enhancement pattern on magnetic resonance imaging (MRI). A 48-year-old, right-handed man presented with a 3-month history of tremor and progressing dementia. Neurologic examination revealed cognitive decline with anterograde amnesia and postural tremor of the fingers. Except for the positive result of serum antinuclear antibody, intense investigations for infectious, rheumatic and neoplastic diseases were negative. Analysis of cerebrospinal fluid showed mild pleocytosis (14 cells/µl). Brain MRI revealed diffuse hyperintense areas in the deep cerebral white matter on T2-weighted images. Gadolinium-enhanced T1-weighted images demonstrated fan-shaped multiple linear enhancements converging to the body of the lateral ventricles. Brain biopsy showed intense infiltration of small lymphocytes without atypia or granuloma mainly within the vessel walls and perivascular spaces. The diagnosis of lymphocytic PACNS was made. Administration of corticosteroid markedly improved the tremor and cognitive dysfunction. MRI after the treatment showed resolution of the abnormal fan-shaped linear enhancement. He returned to his previous occupation. PACNS should be included in the differential diagnosis for fan-shaped linear enhancement converging to the lateral ventricles on MRI in patients with unexplained progressing dementia.

Dropped head syndrome preceding the onset of dementia with Lewy bodies.

A 67-year-old woman developed dropped head. Her neck was severely flexed, with prominent cervical paraspinal muscles, although no parkinsonism was observed. Brain MRI showed no significant findings. We considered dystonia as the cause of the dropped head and administered trihexyphenidyl, an anticholinergic. After 10 years of follow-up, remarkable psychotic symptoms, including hallucinations regarding insects, appeared. Following the discontinuation of trihexyphenidyl, the psychotic symptoms decreased but still remained. (123)I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography ((123)I-IMP SPECT) revealed hypoperfusion in the bilateral occipital lobes. We diagnosed the patient with dementia with Lewy bodies (DLB). This case suggests that dropped head syndrome may precede the onset of DLB.