Cognitive phenotypes in Parkinson's disease: A latent profile analysis.

OBJECTIVES: Neurocognitive disorders in Parkinson's disease (PD) are common and heterogeneous. The aim of this study was to use a data-driven method to describe different cognitive phenotypes in PD and to explore anxiety, depression, and motor disturbances across the different cognitive profiles. METHOD: Latent profile analysis was applied to the neuropsychological performances of 65 patients with idiopathic PD assessed by means of a battery of tests that encompass measures of attention, memory, executive functions, social cognition, language, and visuospatial abilities. RESULTS: A three-cluster model produced the best solution: Cluster A (21.54%) included patients with intact cognition or with a relatively slight cognitive impairment in memory and executive functioning; Cluster B (53.85%) included patients with an intermediate level of cognitive impairment; and Cluster C (24.61%) included patients with the most severe cognitive impairment, with greater deficit compared to Cluster B in executive functioning, and, notably, in tasks with a predominantly posterior cortical basis (naming and visuospatial abilities). The three subgroups did not differ in terms of age, gender, disease duration, motor symptom severity or side of onset, levodopa equivalent daily dose, level of anxiety, or depression; however, patients from Cluster C showed greater impairment than patients from Cluster A in measures of everyday functioning. CONCLUSIONS: We presented a qualitative description of three distinct cognitive phenotypes emerging from a sample of 65 PD patients. The three clusters seem to be related to daily functioning but are independent from the stage of disease, motor functioning, anxiety, and depression. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Late-onset oro-facial dyskinesia in Spinocerebellar Ataxia type 2: a case report.

BACKGROUND: Genetic familiar causes of oro-facial dyskinesia are usually restricted to Huntington's disease, whereas other causes are often missed or underestimated. Here, we report the case of late-onset oro-facial dyskinesia in an elderly patient with a genetic diagnosis of Spinocerebellar Ataxia type 2 (SCA2). CASE PRESENTATION: A 75-year-old man complained of progressive balance difficulty since the age of 60 years, associated with involuntary movements of the mouth and tongue over the last 3 months. No exposure to anti-dopaminergic agents, other neuroleptics, antidepressants, or other drugs was reported. Family history was positive for SCA2 (brother and the son of the brother). At rest, involuntary movements of the mouth and tongue were noted; they appeared partially suppressible and became more evident during stress and voluntary movements. Cognitive examination revealed frontal-executive dysfunction, memory impairment, and attention deficit. Brain magnetic resonance imaging (MRI) disclosed signs of posterior periventricular chronic cerebrovascular disease and a marked ponto-cerebellar atrophy, as confirmed by volumetric MRI analysis. A dopamine transporter imaging scan demonstrated a bilaterally reduced putamen and caudate nucleus uptake. Ataxin-2 (ATXN2) gene analysis revealed a 36 cytosine-adenine-guanine (CAG) repeat expansion, confirming the diagnosis of SCA2. CONCLUSIONS: SCA2 should be considered among the possible causes of adult-onset oro-facial dyskinesia, especially when the family history suggests an inherited cerebellar disorder. Additional clinical features, including parkinsonism and motor neuron disease, may represent relevant cues for an early diagnosis and adequate management.

Facilitatory/inhibitory intracortical imbalance in REM sleep behavior disorder: early electrophysiological marker of neurodegeneration?

STUDY OBJECTIVES: Previous studies found an early impairment of the short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) to transcranial magnetic stimulation (TMS) in Parkinson's disease. However, very little is known on the TMS correlates of rapid eye movement (REM) sleep behavior disorder (RBD), which can precede the onset of a α-synucleinopathy. METHODS: The following TMS measures were obtained from 14 de novo patients with isolated RBD and 14 age-matched healthy controls: resting motor threshold, cortical silent period, latency and amplitude of the motor evoked potentials, SICI, and ICF. A cognitive screening and a quantification of subjective sleepiness (Epworth Sleepiness Scale [ESS]) and depressive symptoms were also performed. RESULTS: Neurological examination, global cognitive functioning, and mood status were normal in all participants. ESS score was higher in patients, although not suggestive of diurnal sleepiness. Compared to controls, patients exhibited a significant decrease of ICF (median 0.8, range 0.5-1.4 vs. 1.9, range 1.4-2.3; p < 0.01) and a clear trend, though not significant, towards a reduction of SICI (median 0.55, range 0.1-1.4 vs. 0.25, range 0.1-0.3), with a large effect size (Cohen's d: -0.848). REM Sleep Atonia Index significantly correlated with SICI. CONCLUSIONS: In still asymptomatic patients for a parkinsonian syndrome or neurodegenerative disorder, changes of ICF and, to a lesser extent, SICI (which are largely mediated by glutamatergic and GABAergic transmission, respectively) might precede the onset of a future neurodegeneration. SICI was correlated with the muscle tone alteration, possibly supporting the proposed RBD model of retrograde influence on the cortex from the brainstem.