A Novel KCNQ2 Variant in a Patient with a Combined Tremor Syndrome.

Background: Tremor disorders have various genetic causes. Case report: A 60-year-old female with a family history of tremor presented a combined tremor syndrome, transient episodes of loss of contact and speech disturbances, as well as distal painful symptoms. Genetic screening revealed a novel heterozygous missense variant in the KCNQ2 gene. Discussion: The KCNQ2 protein regulates action potential firing, and mutations in its gene are associated with epilepsy and neuropathic pain. The identified variant, although of uncertain significance, may disrupt KCNQ2 function and also play a role in tremor pathogenesis. This case highlights the importance of genetic screening in combined tremor disorders.

May Bradykinesia Features Aid in Distinguishing Parkinson's Disease, Essential Tremor, And Healthy Elderly Individuals?

BACKGROUND: Bradykinesia is the hallmark feature of Parkinson's disease (PD); however, it can manifest in other conditions, including essential tremor (ET), and in healthy elderly individuals. OBJECTIVE: Here we assessed whether bradykinesia features aid in distinguishing PD, ET, and healthy elderly individuals. METHODS: We conducted simultaneous video and kinematic recordings of finger tapping in 44 PD patients, 69 ET patients, and 77 healthy elderly individuals. Videos were evaluated blindly by expert neurologists. Kinematic recordings were blindly analyzed. We calculated the inter-raters agreement and compared data among groups. Density plots assessed the overlapping in the distribution of kinematic data. Regression analyses and receiver operating characteristic curves determined how the kinematics influenced the likelihood of belonging to a clinical score category and diagnostic group. RESULTS: The inter-rater agreement was fair (Fleiss K = 0.32). Rater found the highest clinical scores in PD, and higher scores in ET than healthy elderly individuals (p < 0.001). In regard to kinematic analysis, the groups showed variations in movement velocity, with PD presenting the slowest values and ET displaying less velocity than healthy elderly individuals (all ps < 0.001). Additionally, PD patients showed irregular rhythm and sequence effect. However, kinematic data significantly overlapped. Regression analyses showed that kinematic analysis had high specificity in differentiating between PD and healthy elderly individuals. Nonetheless, accuracy decreased when evaluating subjects with intermediate kinematic values, i.e., ET patients. CONCLUSION: Despite a considerable degree of overlap, bradykinesia features vary to some extent in PD, ET, and healthy elderly individuals. Our findings have implications for defining bradykinesia and categorizing patients.

Relationship between risk and protective factors and clinical features of Parkinson's disease.

BACKGROUND: Non-genetic risk factors play a relevant role in Parkinson's disease (PD) development but the relationship between these factors and PD clinical features is unknown. OBJECTIVE: The aim of the present multicenter study was to investigate possible relationship between risk factors and clinical motor and non-motor features in a large sample of PD patients. METHODS: Six hundred ninety-four patients with PD participated. Patients underwent a clinical evaluation assessing motor symptoms and motor complications as well as non-motor symptoms severity. Information regarding pharmacological treatment was also collected. Risk and protective factors were previously identified in the present population and included coffee consumption, cigarette smoking, and physical activity as protective factors and a family history of PD, dyspepsia, exposure to toxic agents and general anesthesia as risk factors. Multiple regression models were used to investigate the relationship between risk factors and clinical variables. RESULTS: Coffee consumption predicted older age at onset (B: 0.527; CI: 0.195; 0.858) and milder motor symptom severity (B: 1.383; CI: 2.646; -0.121). Non-motor symptom severity was more severe in patients with dyspepsia before PD (B: 13.601; CI 5.019; 22.182) and milder in patients who performed physical activity before PD (B: 11.355; CI: 16.443; -6.266). We found no relationship between risk factors and motor complications, motor subtype and pharmacological treatment. CONCLUSIONS: Risk and protective factors of PD development may influence PD clinical features. This finding may represent the first step in the development of new preventive approaches able to delay disease onset and mitigate the extent of clinical manifestations.

No evidence of iron deposition in essential tremor: a susceptibility-weighted imaging study.

OBJECTIVE: To evaluate the role of iron deposition in subcortical nuclei of patients with essential tremor (ET). METHODS: Twenty-three patients with ET underwent a standardized 3T-MRI protocol. We specifically assessed iron deposition using susceptibility-weighted angiography (SWAN) images in seven specific regions of interest (ROIs): the thalamus, putamen, globus pallidus, caudate nucleus, substantia nigra, red nucleus, and dentate nucleus. Tremor in ET patients was clinically assessed using the Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS). ET patient data were compared with data obtained from 23 Parkinson's disease (PD) patients and 14 healthy subjects (HS). RESULTS: No differences in iron deposition in the seven ROIs were found between ET patients and HS. Conversely, PD patients showed increased iron deposition in the substantia nigra in comparison with both ET patients and HS. CONCLUSIONS: Our results indicate the absence of iron deposition in subcortical nuclei of ET patients, which is generally considered a marker of neurodegeneration.