Treatment of dementia with Lewy bodies and Parkinson's disease dementia

Synaptic plasticity and levodopa-induced dyskinesia: electrophysiological and structural abnormalities

Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive degeneration of dopaminergic neurons located in the midbrain. The gold-standard therapy for PD is the restoration of dopamine (DA) levels through the chronic administration of the DA precursor levodopa (L-DOPA). Although levodopa therapy is the main therapeutic approach for PD, its use is limited by the development of very disabling dyskinetic movements, mainly due to the fluctuation of DA cerebral content. Experimental animal models of PD identified in DA D1/ERK-signaling pathway aberrant activation, occurring in striatal projection neurons, coupled with structural spines abnormalities, the molecular and neuronal basis of L-DOPA-induced dyskinesia (LIDs) occurrence. Different electrophysiological approaches allowed the identification of  the alteration of homeostatic structural and synaptic changes, the neuronal bases of LIDs either in vivo in parkinsonian patients or in vitro in experimental animals. Here, we report the most recent studies showing electrophysiological and morphological evidence of aberrant synaptic plasticity in parkinsonian patients during LIDs in different basal ganglia nuclei and also in cortical transmission, accounting for the complexity of the synaptic changes during dyskinesias. All together, these studies suggest that LIDs are associated with a loss of homeostatic synaptic mechanisms.

A preclinical screen to evaluate pharmacotherapies for the treatment of agitation in dementia

Agitation associated with dementia is frequently reported clinically but has received little attention in preclinical models of dementia. The current study used a 7PA2 CM intracerebroventricular injection model of Alzheimer's disease (AD) to assess acute memory impairment, and a bilateral intrahippocampal (IH) injection model of AD (aggregated Aβ1-42 injections) and a bilateral IH injection model of dementia with Lewy bodies (aggregated NAC61-95 injections) to assess chronic memory impairment in the rat. An alternating-lever cyclic-ratio schedule of operant responding was used for data collection, where incorrect lever perseverations measured executive function (memory) and running response rates (RRR) measured behavioral output (agitation). The results indicate that bilateral IH injections of Aβ1-42 and bilateral IH injections of NAC61-95 decreased memory function and increased RRRs, whereas intracerebroventricular injections of 7PA2 CM decreased memory function but did not increase RRRs. These findings show that using the aggregated peptide IH injection models of dementia to induce chronic neurotoxicity, memory decline was accompanied by elevated behavioral output. This demonstrates that IH peptide injection models of dementia provide a preclinical screen for pharmacological interventions used in the treatment of increased behavioral output (agitation), which also establish detrimental side effects on memory.

Antipsychotic Medication Use in the Elderly Patient

The use of antipsychotic medications in the elderly can be very complex and is ever changing. Consideration must be given to not only the physiologic and functional changes normally associated with age but also to the latest data on safety and adverse outcomes associated with using these agents. Because of new and changing information, this article will review the effects of aging, side effects of antipsychotic medications, and the current issues surrounding their use in elderly patients for those clinicians who are not specialists in this area of practice.

Association of sleep quality and dementia among long-lived Chinese older adults

In this study, we examined the existence of relationship between sleep quality and dementia in subjects aged 90 years and above. The sample included 216 men and 444 women. Dementia and sleep quality were measured with 30-item mini-mental state examination (MMSE) and the Pittsburgh sleep quality index, respectively. Subjects with dementia had higher sleep quality score (7.83 ± 2.15 vs. 5.22 ± 2.49; P < 0.0001), longer sleep latency (50.97 ± 21.33 vs. 37.61 ± 12.53; P < 0.0001), and a lower sleep efficiency percentage (73.95 ± 8.783 vs. 81.32 ± 10.21; P < 0.0001) and more likely to report poor sleep quality (25.42 vs.17.13 %; P = 0.035). Subjects with poor sleep quality had significantly lower MMSE scores (P = 0.007) and higher prevalence of dementia (P = 0.042). Multiple logistic regressions were performed by adjusting clinical factors that are thought to be associated with dementia or sleep quality. We found that poor sleep quality was a risk factor for dementia (unadjusted odds ratio (OR) 1.719, 95 % confidence interval (CI) 1.138-2.597; adjusted OR 1.759, 95 % CI 1.012-3.057). There was no significant difference in MMSE scores (11.25 ± 3.40, 16.26 ± 5.14, and 15.43 ± 5.51; P = 0.105) among participants with daily average sleep durations of <5, 5-9, and >9 h, respectively. Among Chinese nonagenarians and centenarians, dementia was correlated with poor sleep quality, longer sleep latency, and lower sleep efficiency percentage.

Levodopa response in dementia with lewy bodies: a 1-year follow-up study

PURPOSE

To evaluate levodopa responsiveness in patients with probable dementia with Lewy bodies (DLB) compared to early Parkinson's disease (PD) patients.

METHODS

Twenty four cases with DLB and 21 with PD underwent a baseline assessment with UPDRS (sub-item II and III) and an acute levodopa challenge test. Positive response to acute levodopa test was defined as an improvement of at least 15% in the tapping test, and at least 25% in the walking test and rigidity or tremor score. Subsequently, all patients were treated continuously with levodopa and evaluated after 6 and 12 months by means of UPDRS II/III.

RESULTS

Positive response to the acute levodopa test was observed in 55% of DLB patients (acute DLB responders), and in 90% of PD patients (acute PD responders). Acute DLB responders showed increased latency, and reduction of both duration and amplitude of response to acute levodopa in comparison with acute PD responders. At the 6-month follow-up visit, acute DLB responders showed a greater motor benefit compared with acute DLB non-responders. This improvement was similar to that observed in PD patients. However, at 1-year follow-up acute DLB responders showed a faster worsening of UPDRS III scores compared with acute PD responders, implying a reduction of levodopa efficacy.

CONCLUSIONS

Positive response to acute levodopa test can occur in DLB patients and may be predictive of long-term benefit of chronic levodopa therapy, although the motor improvement is less impressive than in PD patients.

Levodopa responsiveness in disorders with parkinsonism: a review of the literature

A literature review was conducted to investigate whether or not levodopa (LD) responsiveness (LR) is a useful criterion in the diagnosis of parkinsonian disorders. Although LR does appear to differ among the parkinsonian disorders, there is considerable confusion in the literature. While most patients with Parkinson's disease (PD) have a sustained benefit from LD, a small minority of patients with documented PD do not respond. The literature suggests that the LR rate is higher for multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD) than based on published diagnostic criteria. Magnitude and duration of response to LD and tolerability (time course, type and distribution of dyskinesias, mental effects and motor worsening) may be useful features in distinguishing PD, MSA, PSP, and CBD. Efforts should be directed toward better defining LR when used for diagnostic purposes and in scientific publications.

The patient with Parkinson's disease: part I-treating the motor symptoms; part II-treating the nonmotor symptoms

PURPOSE

This two-part article provides the nurse practitioner (NP) with information on the developments in the pathophysiology and expanded treatment options in the motor and nonmotor symptoms of Parkinson's disease (PD). The discussion provides treatment strategies that may offer improved ability to manage the disabling symptoms of this neurodegenerative disorder.

DATA SOURCES

Review of scientific literature from PubMed search for English language articles on PD from 1998 to 2005 and books or chapters in textbooks published on the disease in the same time frame provided the data source for this article. The content reflects our clinical judgments and experience from clinical practice in the Movement Disorder Clinic at Mayo Clinic Arizona.

CONCLUSIONS

The high prevalence of the disease and important advances in its management means that the NP needs to have knowledge of the disorder and the combination of multiple treatment options available for both the motor and the nonmotor symptoms.

IMPLICATIONS FOR PRACTICE

PD is a progressive neurodegenerative disease affecting 1% of persons over the age of 60 in the United States. As prevalence increases with age, so does the need for early accurate diagnosis and proper treatment of the PD by the clinician. Advances in the treatment for the motor and nonmotor symptoms of PD provide the clinician with increased options to improve the patient's quality of life.

Cognitive change in Parkinson disease

Parkinson disease (PD) is the most common neurodegenerative movement disorder, affecting 1 in 100 individuals over the age of 60. Dementia in the setting of PD (PDD) may be among the most debilitating symptoms associated with disease progression. Estimates of cognitive decline and dementia in PD suggest that up to 14% per year of patients over age 65 with PD will develop some cognitive impairment. Unfortunately, PDD is not well characterized and the relationship of PDD to Alzheimer disease remains unclear. PDD has been proposed as part of a spectrum with dementia with Lewy bodies, and PDD and dementia with Lewy bodies frequently coexist with Alzheimer disease. It is uncertain, however, whether there is a meaningful distinction between the different disorders. It has also been difficult to gain understanding of the interaction of motor and non-motor symptoms that affect quality of life in PD and confound cognitive and psychomotor performance. This review will examine the clinical, cognitive, neuropsychiatric features of cognitive deficits associated with PD, discuss their pathologic basis and propose avenues for future research.

Cortical Lewy body disease and Parkinson's disease dementia

PURPOSE OF REVIEW

The health and socioeconomic impacts of dementia with Lewy bodies and dementia associated with Parkinson's disease have become increasingly recognized. Whilst the nosological status of dementia with Lewy bodies has been better classified as 'Lewy body dementias', both conditions are now believed to represent a disease spectrum, characterized pathologically by synuclein protein and clinically by a variable admixture of cognitive, neuropsychiatric and extrapyramidal features.

RECENT FINDINGS

Recent epidemiological studies are described and clinical and pathological similarities emphasized between dementia with Lewy bodies and Parkinson's disease. A number of investigational techniques are highlighted which have helped to better characterize dementia with Lewy bodies and discriminate it from Alzheimer's disease, whilst also shedding light upon the pathophysiology of both conditions. Finally, the therapeutic aspects of the Lewy body dementias will be considered, concentrating upon studies of the cholinesterase inhibitors.

SUMMARY

The pathology underlying dementia with Lewy bodies and Parkinson's disease is heterogeneous, and is neither stereotyped in its topography nor its composition. Cholinesterase inhibitor drugs improve cognition and neuropsychiatric symptoms but the clinical response is unpredictable. Major future challenges are to better understand the pathophysiological basis underpinning the diseases, what determines clinical phenotypic expression and how disease-modifying therapies may best be developed and deployed.

Recognition and management of neuropsychiatric complications in Parkinson's disease

Parkinson's disease is primarily considered a motor disease characterized by rest tremor, rigidity, bradykinesia and postural disturbances. However, neuropsychiatric complications, including mood and anxiety disorders, fatigue, apathy, psychosis, cognitive impairment, dementia, sleep disorders and addictions, frequently complicate the course of the illness. The pathophysiologic features of these complications are multifaceted and include neuropathophysiologic changes of a degenerative disease, exposure to antiparkinsonian treatments and emotional reactions to having a disabling chronic illness. Changes in mental status have profound implications for the well-being of patients with Parkinson's disease and of their caregivers. Treatment is often efficacious but becomes a challenge in advanced stages of Parkinson's disease. In this article, we review the key clinical features of neuropsychiatric complications in Parkinson's disease as well as what is known about their epidemiologic characteristics, risk factors, pathophysiologic features and management.

Arrestins and two receptor kinases are upregulated in Parkinson's disease with dementia

Arrestins and G proteins-coupled receptor kinases (GRKs) regulate signaling and trafficking of G protein-coupled receptors. We investigated changes in the expression of arrestins and GRKs in the striatum of patients with Parkinson's disease without (PD) or with dementia (PDD) at postmortem using Western blotting and ribonuclease protection assay. Both PD and PDD groups had similar degree of dopamine depletion in all striatal regions. Arrestin proteins and mRNAs were increased in the PDD group throughout striatum. Protein and mRNA of GRK5, the major subtype in the human striatum, and GRK3 were also upregulated, whereas GRK2 and 6 were mostly unchanged. The PD group had lower concentration of arrestins and GRKs than the PDD group. There was no statistical link between the load of Alzheimer's pathology and the expression of these signaling proteins. Upregulation of arrestins and GRK in PDD may confer resistance to the therapeutic effects of levodopa often observed in these patients. In addition, increased arrestin and GRK concentrations may lead to dementia via perturbation of multiple signaling mechanisms.

Cognitive, Affective, and Psychiatric Features of Parkinson's Disease

Nonmotor symptoms, including cognitive deterioration and dementia, depression and apathy, and psychosis, are common in Parkinson's disease. Their presence is associated with a tremendous burden for the patient and family members. This article reviews the pathophysiololgy, risks, impact, major features, diagnosis, and treatment of these symptoms in Parkinson's disease.

Genetics of Parkinson disease: paradigm shifts and future prospects

Parkinson disease is a complex, multifactorial neurodegenerative disease. Although a heritable basis was originally thought unlikely, recent studies have implicated several genes in its pathogenesis, and molecular findings now allow accurate diagnosis and challenge past criteria for defining Parkinson disease. Most importantly, genetic insights provide the rationale for new strategies for prevention or therapy, and have led to animal models of disease in which these strategies can be tested. Neuroprotective therapies can now be designed to slow or halt disease progression in affected subjects and asymptomatic carriers.