Basal ganglia and kinematics modulation: Insights from Parkinson’s and Huntington’s diseases

Movement kinematic variables related to force production can be modulated to respond appropriately to different contexts. We previously showed that in a choice-reaction time and a predictable timed-response task, normal subjects perform reaching movements to the same targets with two different kinematic patterns, a marker of flexibility. Here, we used the two tasks to determine whether basal ganglia are involved in the selection and modulation of movement kinematics and therefore in flexible force production.We tested seventeen patients in the early stages of Parkinson’s disease, eleven pre-symptomatic Huntington’s disease carriers and sixteen age-matched normal controls with the above-mentioned motor tasks.In both patient groups, the difference in kinematics (movement duration, peak velocity and acceleration) between the two tasks was significantly reduced compared to controls, indicating a limited range of choices or flexibility. However, this reduction was skewed in opposite directions in the two disorders, with force production being generally higher in Huntington’s carriers and lower in Parkinson’s patients compared to controls.We conclude that basal ganglia are involved in adapting movement to different contexts and selecting the appropriate movement force. The opposite trends in Parkinson’s and Huntington’s disease suggest that such regulation might depend on the balance between the outputs of direct and indirect pathways.     

Acetylcholinesterase inhibitors in cognitive impairment in Huntington’s disease: A brief review

Huntington’s disease (HD) is a neurodegenerative disease associated with cognitive deficits. Cognitive dysfunction may be present in the early stages of the disease, even before the onset of motor symptoms. The cognitive dysfunction includes executive dysfunction, psychomotor symptoms, visuospatial deficits, perceptual deficits, memory loss and difficulty learning new skills. Acetylcholinesterase inhibitors have shown good effect in the treatment of other types of dementia and it is postulated that it might delay cognitive decline in HD. We reviewed the evidence for Acetylcholinesterase inhibitors in the treatment of cognitive decline and dementia associated with Huntington’s disease. We identified 6 articles that investigated the role of Acetylcholinesterase inhibitors for treatment of cognitive deficits in Huntington’s disease. Following the review, the authors concluded that there is limited evidence for the use of Acetylcholinesterase inhibitors for cognitive impairment in HD.     

Autonomic Dysfunction in Parkinson’s Disease

Recognition of the importance of nonmotor dysfunction as a component of Parkinson’s disease has exploded over the past three decades. Autonomic dysfunction is a frequent and particularly important nonmotor feature because of the broad clinical spectrum it covers. Cardiovascular, gastrointestinal, urinary, sexual, and thermoregulatory abnormalities all can appear in the setting of Parkinson’s disease. Cardiovascular dysfunction is characterized most prominently by orthostatic hypotension. Gastrointestinal dysfunction can involve virtually all levels of the gastrointestinal tract. Urinary dysfunction can entail either too frequent voiding or difficulty voiding. Sexual dysfunction is frequent and frustrating for both patient and partner. Alterations in sweating and body temperature are not widely recognized but often are present. Autonomic dysfunction can significantly and deleteriously impact quality of life for individuals with Parkinson’s disease. Because effective treatment for many aspects of autonomic dysfunction is available, it is vitally important that assessment of autonomic dysfunction be a regular component of the neurologic history and exam and that appropriate treatment be initiated and maintained.Electronic supplementary materialThe online version of this article (10.1007/s13311-020-00897-4) contains supplementary material, which is available to authorized users.Key Words: Autonomic, gastrointestinal, orthostatic hypotension, urinary, erectile dysfunction, thermoregulatory     

Variant patterns in von Willebrand's Disease

Investigation of a group of patients with classical von Willebrand's disease by the additional techniques of ristocetin induced platelet aggregation and quantitative immunoelectrophoresis for factor VIII related antigen, indicate that there is considerable heterogeneity in this condition. On the basis of the results presented, it appears that there could be at least five separate subpatterns in von Willebrand's disease. At present this condition should not be considered a single disease entity, but a syndrome with features which may be the common expression of a number of separate genetic disturbances.     

Illuminating Neural Circuits in Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common neurodegenerative disorder and there is currently no cure. Neural circuit dysfunction is the fundamental mechanism underlying the learning and memory deficits in patients with AD. Therefore, it is important to understand the structural features and mechanisms underlying the deregulated circuits during AD progression, by which new tools for intervention can be developed. Here, we briefly summarize the most recently established cutting-edge experimental approaches and key techniques that enable neural circuit tracing and manipulation of their activity. We also discuss the advantages and limitations of these approaches. Finally, we review the applications of these techniques in the discovery of circuit mechanisms underlying β-amyloid and tau pathologies during AD progression, and as well as the strategies for targeted AD treatments.     

Approach to Cognitive Impairment in Parkinson’s Disease

Cognitive dysfunction is common in Parkinson’s disease (PD) and predicts poor clinical outcomes. It is associated primarily with pathologic involvement of basal forebrain cholinergic and prefrontal dopaminergic systems. Impairments in executive functions, attention, and visuospatial abilities are its hallmark features with eventual involvement of memory and other domains. Subtle symptoms in the premotor and early phases of PD progress to mild cognitive impairment (MCI) which may be present at the time of diagnosis. Eventually, a large majority of PD patients develop dementia with advancing age and longer disease duration, which is usually accompanied by immobility, hallucinations/psychosis, and dysautonomia. Dopaminergic medications and deep brain stimulation help motor dysfunction, but may have potential cognitive side effects. Central acetylcholinesterase inhibitors, and possibly memantine, provide modest and temporary symptomatic relief for dementia, although there is no evidence-based treatment for MCI. There is no proven disease-modifying treatment for cognitive impairment in PD. The symptomatic and disease-modifying role of physical exercise, cognitive training, and neuromodulation on cognitive impairment in PD is under investigation. Multidisciplinary approaches to cognitive impairment with effective treatment of comorbidities, proper rehabilitation, and maintenance of good support systems in addition to pharmaceutical treatment may improve the quality of life of the patients and caregivers.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13311-020-00963-x.Key Words: Parkinson’s disease, dementia, mild cognitive impairment, neuropsychology, cholinesterase inhibitors, deep brain stimulation, neuromodulation, neurorehabilitation.