Parkinson Disease: O'Sullivan SS

O'Sullivan SS, Evans AH, Lees AJ. · Reta Lila Weston Institute of Neurological Studies, Institute of Neurology, University College London, London, England. · CNS Drugs. · Pubmed #19173374 No free full text.

Abstract: Dopamine dysregulation syndrome (DDS) is a relatively recently described iatrogenic disturbance that may complicate long-term symptomatic therapy of Parkinson's disease. Patients with DDS develop an addictive pattern of dopamine replacement therapy (DRT) use, administering doses in excess of those required to control their motor symptoms. The prevalence of DDS in patients attending specialist Parkinson's disease centres is 3-4%. Amongst the behavioural disturbances associated with DDS are punding, which is a complex stereotyped behaviour, and impulse control disorders (ICDs), such as pathological gambling, hypersexuality, compulsive shopping and compulsive eating. We review the risk factors and potential mechanisms for the development of DDS, including personality traits, potential genetic influences and Parkinson's disease-related cognitive deficits. Impulsive personality traits are prominent in patients developing DDS, and have been previously associated with the development of substance dependence. Candidate genes affecting the dopamine 'D(2)-like' receptor family have been associated with impulsive personality traits in addition to drug and nondrug addictions. Impaired decision making is implicated in addictive behaviours, and decision-making abilities can be influenced by dopaminergic medications. In Parkinson's disease, disruption of the reciprocal loops between the striatum and structures in the prefrontal cortex following dopamine depletion may predispose to DDS. The role of DRT in DDS is discussed, with particular reference to models of addiction, suggesting that compulsive drug use is due to progressive neuroadaptations in dopamine projections to the accumbens-related circuitry. Evidence for neuroadaptations and sensitization occurring in DDS include enhanced levodopa-induced ventral striatal dopamine release. Levodopa is still considered the most potent trigger for DDS in Parkinson's disease, but subcutaneous apomorphine and oral dopamine agonists may also be responsible. In the management of DDS, further research is needed to identify at-risk groups, thereby facilitating more effective early intervention. Therefore, an increased awareness of the syndrome amongst treating physicians is vital. Medication reduction strategies are employed, particularly with regard to avoiding rapidly acting 'booster' DRT formulations. Psychosocial treatments, including cognitive-behavioural therapy, have been beneficial in treating substance use disorders and ICDs in non-Parkinson's disease patients, but there are currently no published trials of psychological interventions in DDS. Further studies are also required to identify factors that can predict those patients with DDS or ICDs who will derive benefit from surgical interventions such as deep brain stimulation.

Healy DG, Falchi M, O'Sullivan SS, Bonifati V, Durr A, Bressman S, Brice A, Aasly J, Zabetian CP, Goldwurm S, Ferreira JJ, Tolosa E, Kay DM, Klein C, Williams DR, Marras C, Lang AE, Wszolek ZK, Berciano J, Schapira AH, Lynch T, Bhatia KP, Gasser T, Lees AJ, Wood NW, Anonymous00013. · Department of Clinical Neurosciences, Institute of Neurology, University College London, London, UK. · Lancet Neurol. · Pubmed #18539534 No free full text.

Abstract: BACKGROUND: Mutations in LRRK2, the gene that encodes leucine-rich repeat kinase 2, are a cause of Parkinson's disease (PD). The International LRRK2 Consortium was established to answer three key clinical questions: can LRRK2-associated PD be distinguished from idiopathic PD; which mutations in LRRK2 are pathogenic; and what is the age-specific cumulative risk of PD for individuals who inherit or are at risk of inheriting a deleterious mutation in LRRK2? METHODS: Researchers from 21 centres across the world collaborated on this study. The frequency of the common LRRK2 Gly2019Ser mutation was estimated on the basis of data from 24 populations worldwide, and the penetrance of the mutation was defined in 1045 people with mutations in LRRK2 from 133 families. The LRRK2 phenotype was defined on the basis of 59 motor and non-motor symptoms in 356 patients with LRRK2-associated PD and compared with the symptoms of 543 patients with pathologically proven idiopathic PD. FINDINGS: Six mutations met the consortium's criteria for being proven pathogenic. The frequency of the common LRRK2 Gly2019Ser mutation was 1% of patients with sporadic PD and 4% of patients with hereditary PD; the frequency was highest in the middle east and higher in southern Europe than in northern Europe. The risk of PD for a person who inherits the LRRK2 Gly2019Ser mutation was 28% at age 59 years, 51% at 69 years, and 74% at 79 years. The motor symptoms (eg, disease severity, rate of progression, occurrence of falls, and dyskinesia) and non-motor symptoms (eg, cognition and olfaction) of LRRK2-associated PD were more benign than those of idiopathic PD. INTERPRETATION: Mutations in LRRK2 are a clinically relevant cause of PD that merit testing in patients with hereditary PD and in subgroups of patients with PD. However, this knowledge should be applied with caution in the diagnosis and counselling of patients. FUNDING: UK Medical Research Council; UK Parkinson's Disease Society; UK Brain Research Trust; Internationaal Parkinson Fonds; Volkswagen Foundation; National Institutes of Health: National Institute of Neurological Disorders and Stroke and National Institute of Aging; Udall Parkinson's Disease Centre of Excellence; Pacific Alzheimer Research Foundation Centre; Italian Telethon Foundation; Fondazione Grigioni per il Morbo di Parkinson; Michael J Fox Foundation for Parkinson's Research; Safra Global Genetics Consortium; US Department of Veterans Affairs; French Agence Nationale de la Recherche.

Lashley T, Holton JL, Gray E, Kirkham K, O'Sullivan SS, Hilbig A, Wood NW, Lees AJ, Revesz T. · Queen Square Brain Bank for Neurological Disorders, Department of Molecular Neuroscience, UCL Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK. · Acta Neuropathol. · Pubmed #18185940 No free full text.

Abstract: Amyloid-beta (Abeta) peptide pathology in Alzheimer's disease (AD) comprises extracellular plaques and cerebral amyloid angiopathy (CAA). In Parkinson's disease (PD), alpha-synuclein forms intraneuronal Lewy bodies (LBs), and cortical LBs are thought to play a major role in cognitive decline designated as PD with dementia. As there is increasing evidence that Abeta may also promote alpha-synuclein fibrillization, we assessed the relationship between LB pathology and Abeta deposition in 40 cases of PD and 20 age-matched controls. In five cortical areas, we established the severity of Abeta plaque load using an approach similar to that recommended by CERAD in AD. LB densities were determined using a morphometric approach. CAA was graded using previously described scales. The APOE genotype was established in 38 PD and 19 control cases. We have found that the overall Abeta plaque burden and, in particular, the diffuse plaque load shows a statistically significant 'large' correlation with the overall cortical LB burden. The strength of this correlation further increases in PD cases (about 50% of the cases) with moderate to high Abeta plaque load. The APOE epsilon4 allele is over-represented in this subgroup. Our data indicate a strong association between pathologically identifiable Abeta plaque burden and alpha-synuclein load in cerebral cortex and provide indirect evidence that Abeta pathology is likely to be an important factor contributing to cognitive decline in a subgroup of PD patients.

O'Sullivan SS, Evans AH, Lees AJ. · Reta Lila Weston Institute of Neurological Studies, Institute of Neurology, University College London, London, UK. · Pract Neurol. · Pubmed #18024780 No free full text.

This publication has no abstract.

O'Sullivan SS, Williams DR, Gallagher DA, Massey LA, Silveira-Moriyama L, Lees AJ. · Reta Lila Weston Institute of Neurological Studies, Institute of Neurology, University College London, London, United Kingdom. · Mov Disord. · Pubmed #17994582 No free full text.

Abstract: Nonmotor symptoms (NMS) are increasingly recognized as a significant cause of morbidity in later stages of Parkinson's disease (PD). Prodromal NMS are also a well recognized component of the clinical picture in some patients but the prevalence of NMS as presenting complaints, and their impact on clinical management, in pathologically-proven cases of PD is unknown. The presenting complaints of 433 cases of pathologically-proven PD archived at the Queen Square Brain Bank for Neurological Diseases were identified from the clinical case notes. 91/433 (21%) of patients with PD presented with NMS of which the most frequent were pain (15%), urinary dysfunction (3.9%), anxiety, or depression (2.5%). Presenting with NMS is associated with a delayed diagnosis of PD (Mann-Whitney U, P = 0.001). These patients were more likely to be misdiagnosed initially and were more likely to have been referred to orthopedic surgeons or rheumatologists than neurologists (nonmotor group 5.5% vs. motor group 44.2%, chi(2) P < 0.0001). NMS are commonly seen as presenting complaints in pathologically confirmed PD, and initial misdiagnosis may be associated with potentially inappropriate medical interventions. Presenting with NMS does not affect the motor response to medication, but is associated with shorter disease duration (chi(2) P = 0.016).

Gallagher DA, O'Sullivan SS, Evans AH, Lees AJ, Schrag A. · Department of Clinical Neurosciences, Royal Free & University College Medical School, London, United Kingdom. · Mov Disord. · Pubmed #17580327 No free full text.

Abstract: Pathological gambling (PG) has been reported as a complication of the treatment of Parkinson's disease (PD). We examined all published cases of PG for prevalence and risk factors of this complication, the relationship of PG and use of dopamine agonists (DA), and the relationship of PG to the dopamine dysregulation syndrome (DDS). The prevalence of PG in prospective studies of PD patients using DA has been reported between 2.3 and 8%, compared to approximately 1% in the general population. As in the general population, PD patients with this complication are often young, male and have psychiatric co-morbidity. The vast majority are on DA, often at maximum dose or above. Differences between oral DA failed to reach significance. PG associated with levodopa monotherapy is uncommon, but in the majority of cases levodopa is co-prescribed, suggesting possible cross-sensitization of brain systems mediating reward. PG can occur with DDS but often occurs in isolation. In contrast to DDS, escalation and self regulation of anti-parkinsonian medication are not usually seen. PG in patients with PD using DA is higher than PG reported in the general population, but shares similar characteristics and risk factors. PG is predominantly associated with oral DA. It often occurs in isolation and may not be associated with DDS, which typically occurs on treatment with levodopa or subcutaneous apomorphine.

O'Sullivan SS, Holton JL, Massey LA, Williams DR, Revesz T, Lees AJ. · No affiliation provided · J Neurol Neurosurg Psychiatry. · Pubmed #17951280 No free full text.

This publication has no abstract.

O'Sullivan SS, Lees AJ. · No affiliation provided · Lancet Neurol. · Pubmed #17434085 No free full text.

This publication has no abstract.