Many investigators have reported that the substantia nigra in Parkinson’s disease (PD) shows signs of chronic inflammation. However, the potential role of inflammation in causing death of dopamine neurons remains controversial. The authors of the present study hypothesized that inflammatory mediators that are increased in subjects with autoimmune disease would predispose them to develop PD. They performed a population-based study of 13,695 patients in the Danish National Hospital Register who had a primary diagnosis of PD. Subjects were compared to 68,445 control subjects in the registry who did not have a diagnosis of PD. They then measured which subjects also had a hospital diagnosis of one of 32 selected autoimmune diseases as recorded 5 or more years prior to their index date in the Danish Register files. Data analysis showed no overall association of autoimmune disease with increased risk of PD. However, further analysis showed a 30% decrease in risk of PD in a subgroup that was composed mostly of patients with a diagnosis of rheumatoid arthritis. The authors suggest that chronic treatment with non-steroidal anti-inflammatory drugs (NSAIDs), which is a mainstay of rheumatoid arthritis therapy, might be responsible for reducing the risk of PD. Further studies will be needed to establish whether or not NSAIDs reduce the risk of PD.


Neurology 2009; 73-1462-1468
http://www.neurology.org

Diminished driving safety among Parkinson’s disease patients is a significant concern for patients, families and clinicians. Uc et al compared road safety and its predictors in a group of actively driving PD patients with an age-matched control group. Cognitive, visual, and motor tests comprised the off-road testing battery, conducted with PD patients in the “on” state. All subjects performed a 45-minute experimental drive on a standardized route in an instrumented vehicle. Familiarity with the driving environment was assessed with a yes/no question. Safety errors were judged by a driving expert based on video data review. PD drivers committed more total safety errors than controls (41.6 ± 14.6 vs 32.9 ± 12.3, p < 0.0001). 77.4% of PD drivers had more errors than the median error count among controls. After adjustment for demographic factors and familiarity with the environment, group differences persisted for errors in lane observance and stop signs, but differences in other categories become insignificant. Predictors of driving errors among PD subjects included older age and worse performances on measures of visual acuity, contrast sensitivity, attention, visuospatial abilities, visual memory and general cognition. In a multivariate model, visual processing speed and attention and far visual acuity were jointly predictive of error counts. This study demonstrates that while there is variability in driving performance among PD patients, those with impairments in visual perception and cognition are likely to have poor road safety, particularly in unfamiliar environments. Maximizing visual acuity by correcting refractive errors and avoiding driving in unfamiliar surroundings are two simple measures that can improve driving performance in PD patients.

Neurology 2009; 73:2112-2119 http://www.neurology.org

Given that postural instability in Parkinson Disease (PD) is poorly responsive to dopaminergic augmentation, Bohnen et al evaluated the relationship between frequent falling and acetylcholinesterase activity in 44 PD subjects and 15 non-PD controls using clinical measurements as well as PET outcomes. Imaging for both cholinergic ([11C]methyl-4-piperidinylpropionate acetylcholinesterase) and dopaminergic activity ([11C]dihydrotetrabenazine vesicular monoamine transporter type 2) was performed in this nondemented cross section of subjects with varying degrees of postural instability (H&Y Stages I-III). PD subjects were divided into those with a history of falling (17) or not falling (27). Compared to non-PD controls, acetylcholinesterase in the cortex was reduced in those who fall by an average of 12.3% versus 6.6% in those without falls. In the thalamus, which receives cholinergic input from the pedunculopontine nucleus (PPN), acetylcholinesterase activity was lower by 11.8% only in the falling subjects. On the other hand, no differences in nigrostriatal dopaminergic activity was detected between the 2 PD groups. These investigators concluded that reduced acetylcholine and not dopamine activity is associated with falling in Parkinson Disease. They also suggest that thalamic acetylcholine turnover may be reduced because of dysfunction of the PPN, a site implicated in other work as etiologic in problems of gait and postural control in PD. “Our findings and prior work raise the question as to whether cholinergic therapy may have a place in the management of mobility problems in PD.”

Neurology 2009; 73(20):1670-6 http://www.ncbi.nlm.nih.gov/pubmed/19917989?log$=activity