Role of dopamine D3 and serotonin 5-HT1A receptors in l-DOPA-induced dyskinesias and effects of sarizotan in the 6-hydroxydopamine-lesioned rat model of Parkinson's disease

Sarizotan, a 5-HT1A agonist with additional affinity for D3 and D4 receptors, has been demonstrated to have anti-dyskinetic effects. The mechanism by which these effects occur is not clear. Using unilateral 6-hydroxydopamine-lesioned rats that received chronic intraperitoneal (ip) administration of L-3,4-dihydroxyphenylalanine (L-DOPA) we investigated the involvement of D3 and 5-HT1A receptors in the effects of sarizotan on contraversive circling and abnormal involuntary movements (AIMs). Before sensitization by chronic L-DOPA treatment (12.5 with 3.25 mg/kg benserazide ip, twice daily for 21 days), no effect of the selective D3 agonist, PD128907 (1 or 3 mg/kg ip), or the selectiveD3 antagonist,GR103691 (0.5 or 1.5 mg/kg ip), was observed. Treatment with sarizotan (1 or 5 mg/kg ip) dosedependently inhibited the L-DOPA-induced contraversive turning and AIMs. In co-treatment with the 5-HT1A antagonist, WAY100635 (1 mg/kg ip), sarizotan failed to affect this behaviour, confirming the prominent 5-HT1A receptor-mediated mechanism of action. In the presence of PD128907 (3 mg/kg ip), the effects of sarizotan on contraversive turning, locomotive dyskinesia and axial dystonia, but not on orolingual and forelimb dyskinesia, were blocked. On its own, PD128907 had no effect on the behavioural effects of L-DOPA except that it tended to reduce orolingual and forelimb dyskinesia. GR103691 had no effect on its own or in combination with sarizotan. These data identify an involvement of D3 receptors in the action of sarizotan on some, but not all L-DOPA-induced motor side effects. This selective involvement is in contrast to the more general involvement of 5-HT1A receptors in the anti-dyskinetic effects of sarizotan.

Protocol for a home-based integrated physical therapy program to reduce falls and improve mobility in people with Parkinson’s disease

Background The high incidence of falls associated with Parkinson’s disease (PD) increases the risk of injuries and immobility and compromises quality of life. Although falls education and strengthening programs have shown some benefit in healthy older people, the ability of physical therapy interventions in home settings to reduce falls and improve mobility in people with Parkinson’s has not been convincingly demonstrated.
Methods/design 180 community living people with PD will be randomly allocated to receive either a home-based integrated rehabilitation program (progressive resistance strength training, movement strategy training and falls education) or a home-based life skills program (control intervention). Both programs comprise one hour of treatment and one hour of structured homework per week over six weeks of home therapy. Blinded assessments occurring before therapy commences, the week after completion of therapy and 12 months following intervention will establish both the immediate and long-term benefits of home-based rehabilitation. The number of falls, number of repeat falls, falls rate and time to first fall will be the primary measures used to quantify outcome. The economic costs associated with injurious falls, and the costs of running the integrated rehabilitation program from a health system perspective will be established. The effects of intervention on motor and global disability and on quality of life will also be examined.
Discussion This study will provide new evidence on the outcomes and cost effectiveness of home-based movement rehabilitation programs for people living with PD.

Cost effectiveness of preventing falls and improving mobility in people with Parkinson disease : protocol for an economic evaluation alongside a clinical trial

Background Cost of illness studies show that Parkinson disease (PD) is costly for individuals, the healthcare system and society. The costs of PD include both direct and indirect costs associated with falls and related injuries.
Methods This protocol describes a prospective economic analysis conducted alongside a randomised controlled trial (RCT). It evaluates whether physical therapy is more cost effective than usual care from the perspective of the health care system. Cost effectiveness will be evaluated using a three-way comparison of the cost per fall averted and the cost per quality adjusted life year saved across two physical therapy interventions and a control group.
Conclusion This study has the potential to determine whether targetted physical therapy as an adjunct to standard care can be cost effective in reducing falls in people with PD.

A randomized controlled trial to reduce falls in people with Parkinson's Disease

Background. Falls are common and disabling in people with Parkinson's disease (PD). There is a need to quantify the effects of movement rehabilitation on falls in PD. Objective. To evaluate 2 physical therapy interventions in reducing falls in PD. Methods. We randomized 210 people with PD to 3 groups: progressive resistance strength training coupled with falls prevention education, movement strategy training combined with falls prevention education, and life-skills information (control). All received 8 weeks of out-patient therapy once per week and a structured home program. The primary end point was the falls rate, recorded prospectively over a 12 month period, starting from the completion of the intervention. Secondary outcomes were walking speed, disability, and quality of life. Results. A total of 1547 falls were reported for the trial. The falls rate was higher in the control group compared with the groups that received strength training or strategy training. There were 193 falls for the progressive resistance strength training group, 441 for the movement strategy group and 913 for the control group. The strength training group had 84.9% fewer falls than controls (incidence rate ratio [IRR] = 0.151, 95% CI 0.071-0.322, P < .001). The movement strategy training group had 61.5% fewer falls than controls (IRR = 0.385, 95% CI 0.184-0.808, P = .012). Disability scores improved in the intervention groups following therapy while deteriorating in the control group. Conclusions. Rehabilitation combining falls prevention education with strength training or movement strategy training reduces the rate of falls in people with mild to moderately severe PD and is feasible.