Neuropsychological testing: bedside approaches

Neuropsychological Evaluations in Limbic Encephalitis

Limbic encephalitis (LE) can cause dynamic and permanent impairment of cognition and behavior. In clinical practice, the question arises as to which cognitive and behavioral domains are affected by LE and which assessment is suited to monitor the disease progress and the success of treatment. Current findings on cognition and behavior in LE are reviewed and discussed based on current guidelines and consensus papers. In addition, we outline approaches for the neuropsychological monitoring of LE and its treatment. Dependent on disease acuity and severity, LE leads to episodic long-term memory dysfunction in different variants (e.g., anterograde memory impairment, accelerated long-term forgetting, and affection of autobiographical memory) and executive deficits. In addition, affective disorders are very common. More severe psychiatric symptoms may occur as well. In the course of the disease, dynamic phases with functional recovery must be differentiated from residual defect states. Evidence-based neuropsychological diagnostics should be conducted ideally before treatment initiation and reassessments are indicated when any progress is suggested, and when decisive anti-seizure or immunomodulatory treatment changes are made. Cognition and behavior may but must not run in synchrony with seizures, MRI pathology, or immune parameters. Cognitive and behavioral problems are integral aspects of LE and represent important biomarkers of disease acuity, progress, and therapy response beyond and in addition to parameters of immunology, neurological symptoms, and brain imaging. Thus, evidence-based neuropsychological assessments are essential for the diagnostic workup of patients with suspected or diagnosed limbic encephalitis, for treatment decisions, and disease and treatment monitoring.

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.