Preoperative Electroencephalography-Based Machine Learning Predicts Cognitive Deterioration After Subthalamic Deep Brain Stimulation.

BACKGROUND: Subthalamic deep brain stimulation (STN DBS) may relieve refractory motor complications in Parkinson's disease (PD) patients. Despite careful screening, it remains difficult to determine severity of alpha-synucleinopathy involvement which influences the risk of postoperative complications including cognitive deterioration. Quantitative electroencephalography (qEEG) reflects cognitive dysfunction in PD and may provide biomarkers of postoperative cognitive decline. OBJECTIVE: To develop an automated machine learning model based on preoperative EEG data to predict cognitive deterioration 1 year after STN DBS. METHODS: Sixty DBS candidates were included; 42 patients had available preoperative EEGs to compute a fully automated machine learning model. Movement Disorder Society criteria classified patients as cognitively stable or deteriorated at 1-year follow-up. A total of 16,674 EEG-features were extracted per patient; a Boruta algorithm selected EEG-features to reflect representative neurophysiological signatures for each class. A random forest classifier with 10-fold cross-validation with Bayesian optimization provided class-differentiation. RESULTS: Tweny-five patients were classified as cognitively stable and 17 patients demonstrated cognitive decline. The model differentiated classes with a mean (SD) accuracy of 0.88 (0.05), with a positive predictive value of 91.4% (95% CI 82.9, 95.9) and negative predictive value of 85.0% (95% CI 81.9, 91.4). Predicted probabilities between classes were highly differential (hazard ratio 11.14 [95% CI 7.25, 17.12]); the risk of cognitive decline in patients with high probabilities of being prognosticated as cognitively stable (>0.5) was very limited. CONCLUSIONS: Preoperative EEGs can predict cognitive deterioration after STN DBS with high accuracy. Cortical neurophysiological alterations may indicate future cognitive decline and can be used as biomarkers during the DBS screening. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Monomia calla, a new species of swimming crab (Decapoda, Portunidae) from Madagascar and the Philippines.

A new species of portunid crab (Brachyura: Portunidae) from southern Madagascar and central Philippines is described. Monomia calla sp. nov. is most similar in morphology to M. lecromi (Moosa, 1996) from the Chesterfield Islands in the southwestern Pacific Ocean, and M. rubromarginata (Lanchester, 1900) from the South China Sea, Singapore, Malay Archipelago and the northern half of Australia. The new species can be easily distinguished from all congeners by the distinctive morphology of the male first gonopod. The number of species of the Indo-West Pacific genus Monomia now stands at 12.

Cycloachelous levigatus sp. nov., a new swimming crab (Crustacea: Decapoda: Portunidae) from the South China Sea.

A new species of portunid crab from the genus Cycloachelous Ward, 1942 is described from Vietnamese waters. Cycloachelous levigatus sp. nov. is morphologically most similar to C. orbitosinus (Rathbun, 1911), which was originally described from the syntype series collected from Western Pacific area (Cargados Carajos Islands, Amirante Islands, Seychelles) and C. octodentatus (Gordon, 1938) described from one single male from Singapore. There are differences in the sternal segments, third maxilliped, chela, abdomen and male gonopode shapes. The specific status of C. levigatus sp. nov. is also clearly supported by molecular data. Aside from a comparison of this new species with other known congeners, new photographs of syntypes of C. orbitosinus and the holotype of C. octodentatus are also provided.

Xiphonectes aculeatus sp. nov., a new swimming crab (Crustacea: Decapoda: Portunidae) from Madagascar.

Here we describe a new species of Xiphonectes A. Milne-Edwards, 1873 (Brachyura: Portunidae) from southern Madagascar. Xiphonectes aculeatus sp. nov. is morphologically most similar to X. latibrachium (Rathbun, 1906) from Hawaii, and X. paralatibrachium Crosnier, 2002, from the Marquesas Islands, French Polynesia. All three species have a carapace with six anterolateral teeth, a long spine on the inner dorsal margin of the cheliped carpus, and a produced, flattened, anterior region on the third maxilliped merus. Among these species, Xiphonectes aculeatus sp. nov. is easily distinguished by the acutely produced posterodistal angle on the meri of its swimming legs, dorsal and marginal structures on its carapace, and most notably, the shape of its frontal teeth.

Monomia lucida sp. nov., a new swimming crab (Crustacea: Decapoda: Portunidae) from the South China Sea.

A new species of the portunid genus, Monomia Gistel, 1848, is described from the South China Sea in Vietnam. Monomia lucida sp. nov. is morphologically most similar to M. argentata (A. Milne-Edwards, 1861), which was originally described from Sarawak, on the island of Borneo. In addition to the stout, forward-directed anterolateral teeth of the carapace, the subrectangular sixth segment of the male pleon, and the long and slender laterally bent first gonopods, adults of the new species reach a greater size, and can also be distinguished from M. argentata by the colour pattern on the natatory dactylus. The independent specific status of M. lucida sp. nov. is also supported by molecular evidence. Aside from a comparison of this new species with other known congeners, new photographs of the holotype of M. samoensis (Ward, 1939) are also provided.