Functional brain imaging of cognitive dysfunction in Parkinson's disease

Abstract

Multiple factors are involved in the development of cognitive impairment in Parkinson's disease (PD) and related disorders. Notably, several underlying factors, such as monoaminergic dysfunction, Lewy body pathology, Alzheimer disease-like pathology and cerebrovascular disease are implied in the PD pathophysiology of cognitive impairment. The mesocortical dopaminergic system is associated with executive functions which are frequently affected in PD and are influenced by local levodopa concentration, dopamine metabolism and baseline performance status. The ventral striatum and frontal cortex are associated with impulse control disorders reported in PD patients treated with dopamine replacement therapy. Cholinergic impairment in PD plays a cardinal role in the development of dementia. Acetylcholinesterase positron emission tomography demonstrates that posterior brain areas are related to cognitive decline in PD patients. Amyloid radiotracer illustrates that patients with PD with severe cognitive impairment were prone to accompanied cortical amyloid deposition. Metabolism/perfusion change associated with cognitive impairment in PD, so-called PD related cognitive pattern, is characterised by reduced frontoparietal activity and is an effective way to differentiate and monitor cognitive function of individual PD patients. Cognitive impairment in PD cannot be explained by a single mechanism and is entangled by multiple factors. Imaging studies can unravel each pathological domain, further shed light on the interrelation between different pathomechanisms, not only in PD but also in other dementia related disorders, and thereby integrate its interpretation to apply to therapeutics in individual patients.

Brain activity during walking: A systematic review

“…However, while our review does not especially addresses a neurological disease (e.g. Parkinson disease), we would like to refer to other reviews which deal with cognitive dysfunctions and the resulting motor limitations (Grabli et al, 2012;Heremans et al, 2013;Hirano et al, 2012;Iansek et al, 2013;Lindenbach and Bishop, 2013;Martinu and Monchi, 2013;Ricciardi et al, 2014;Silbert and Kaye, 2010;Vercruysse et al, 2014). Interestingly, exercise treatments are helpful to improve cognitive and motor symptoms in Parkinson disease (Ahlskog, 2011;Murray et al, 2014;Petzinger et al, 2013).…”

Differential Functional Connectivity Alterations of Two Subdivisions within the Right dlPFC in Parkinson's Disease

“…Affection of cognitive abilities in PD has mainly been attributed to disturbance of frontostriatal circuits caused by dopaminergic depletion (Owen, 2004; Leh et al, 2010). In this regard, the prefrontal cortex, and the dorsolateral prefrontal cortex (dlPFC) in particular, have been repeatedly reported by neuroimaging studies to show alterations in their function and connectivity in PD (e.g., Cools et al, 2002; Lewis et al, 2003; Monchi et al, 2007; Hirano et al, 2012; Disbrow et al, 2013). The observed alterations in dlPFC function have been mainly associated with PD related impairment in executive function (EF).…”

Large-scale resting state network correlates of cognitive impairment in Parkinson's disease and related dopaminergic deficits

“…Numerous studies on cognitive dysfunction associated with PD have revealed structural and functional abnormalities within the cortico-strio-thalamo-cortical circuits, known to be largely modulated by the dopaminergic system (Hirano et al, 2012; Christopher and Strafella, 2013). …”