Data related to psychiatric manifestations in subacute sclerosing panencephalitis (SSPE) is currently available only in the form of isolated case reports. In this systematic review, we evaluated the spectrum of psychiatric manifestations and their impact on the course and outcome of SSPE. Data were obtained from 4 databases (PubMed, Embase, Scopus, and Google Scholar), with the most recent search conducted on March 27, 2023. The PRISMA guidelines were followed, and the PROSPERO registration number for the protocol is CRD42023408227. SSPE was diagnosed using Dyken’s criteria. Extracted data were recorded in an Excel spreadsheet. To evaluate the quality of the data, the Joanna Briggs Institute Critical Appraisal tool was employed. Our search resulted in 30 published reports of 32 patients. The mean age was 17.9 years. Schizophrenia, catatonia, and poorly characterized psychotic illnesses were the 3 most common psychiatric presentations that were seen in 63% (20/32) of cases. Catatonia was seen in 4 patients. Affective disorders, mania, and depression were reported among 22% (7/32) cases. In approximately 81% (26/32) cases, the course of SSPE was acute fulminant. Treatment with antipsychotic drugs had poor or no response. Out of 17 patients, who received antipsychotic drugs, 6 patients noted severe extrapyramidal adverse effects. SSPE often masquerades as a psychiatric disorder. Unresponsive psychiatric symptoms, early extrapyramidal signs, and progressive encephalopathy indicate SSPE.

Mercury (Hg) exists in the environment as inorganic (metallic Hg vapor, mercurous and mercuric salts) or organic (bonded to a structure containing carbon atoms) forms. Neurotoxic effect of Hg is known for years. While the organic form (methylmercury (meHg)) led to the Minamata incidence in Japan and “wonder-wheat” disaster in Iraq, the “mad hatters” and “Danbury shakes” were related to the inorganic elemental form (Hg vapor). Human exposure to toxic Hg continues in the modern world to a large extent by artisanal gold mining, biomass combustion, chloralkali production, and indigenous medicine use to name a few. Heavy industrial use of Hg contaminates air and landfills, affecting the aquatic ecosystem and marine food chain. A detailed social and occupational history with a high index of clinical suspicion is required to not miss this toxic etiology for movement disorders like ataxia, tremor, or myoclonus. In this review, we have discussed the past and present global health impact of Hg from a movement disorder perspective. The connection of Hg with neurodegeneration and autoimmunity has been highlighted. We have also discussed the role of chelating agents and the preventive strategies to combat the neurotoxic effects of Hg in the modern world.

Background: Psychogenic movement disorders (PMD) is a group of disorders that cannot be attributed to any structural or biochemical abnormality, but has an underlying psychiatric illness. The profile of PMD varies according to country and socioeconomic factors. Methods: The present study reports the clinical profile of patients with PMD from India. Seventy-three patients with documented or clinically established PMD were seen over a period of 14 years with detailed neurological and psychiatric examinations. Results: The mean age at presentation was 29.1±15.1 years (women, 51%). Approximately 30% were ≤18 years of age (boys, 63.6%). The onset of symptoms was abrupt in 61.6% and the initial body part most often affected was right upper limb (adults, 29.4%; children, 31.8%). Tremor was observed in 31.4% of adults and 9% of children, whereas myoclonus was more common in children (36.4%). Tremors were more often seen in women (42.3%) than in men (20%), whereas myoclonus was almost equally prevalent in girls (37.5%) and boys (35.7%). Depression was the most common psychiatric comorbidity (men, 16%; women, 15.4%). About 42.5% required hospital admission and 57.5% had significant reduction or complete cessation of PMD after counseling, antidepressants, and/ or placebo. Conclusions: PMD was equally prevalent among women and men. Tremor was most often observed in adults, whereas myoclonus was most often observed in children. Electrophysiology and placebo were useful supplementary tools for diagnosing PMD.

Subjective tinnitus (heard only by the patient) is a common otological complaint. Objective tinnitus (heard by the examiner as well as the patient) is extremely rare. There are only a few cases of objective tinnitus, secondary to middle-ear myoclonus, described in the literature.

We present the case of a child with bilateral, congenital, objective tinnitus, secondary to middle-ear myoclonus, with otherwise normal hearing thresholds (250Hz-8kHz), and with no evidence of intra-cerebral or systemic disorders. No similar case has been reported in the world literature.

Tinnitus produced by middle-ear myoclonus is a rare condition. In this article, a rare case of unilateral continuous high-frequency objective tinnitus caused by middle-ear myoclonus is described. This condition appears to be the second case reported in the literature. Otoscopic examination revealed visible rhythmic movements of the tympanic membrane. Weak clicking sounds were heard around the right ear by auscultation. Direct stimulation of the soft palate showed no evidence of palated myoclonus. Tympanometry confirmed rhythmic changes in the middle-ear compliance. The condition was effectively treated with a muscle relaxant (orphenadrine citrate).