Hallucinations in Parkinson disease in the prelevodopa era
ABSTRACT Whether chronic hallucinations belong to the natural history of untreated Parkinson disease (PD) remains undetermined. For early authors such as Gowers or Charcot and his followers, hallucinations that occurred in the course of PD either accompanied the final phase of the disease or reflected comorbidities. However, a few authors observed that hallucinations could occur in PD patients with severe depression, confusion, or dementia. Interest in hallucinations with parkinsonism increased with the outbreak of von Economo encephalitis, as they were more frequent than in PD, provoking new pathophysiologic questions. Later studies on mental symptoms in parkinsonism were often based on series that pooled patients with PD and postencephalitic syndromes, confounding a clear analysis. It remains difficult to estimate the prevalence of hallucinations in the natural course of PD before the introduction of levodopa therapy. The lack of prospective studies, the wide early use of anticholinergics and ergots compounds, and the absence of dementia with Lewy bodies in the nosology of the time are further limitations. Even with these limitations, historical descriptions of PD from the prelevodopa era suggest that hallucinations may be part of PD itself, especially in the context of late dementia, depression, or nonspecific encephalopathy.
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ABSTRACT: OBJECTIVE: To examine the prevalence, incidence and risk factors associated with visual hallucinations (VHs) amongst people suffering from Parkinson's disease (PD). METHODS: We recruited 513 patients with PD from movement disorder and PD clinics within three sites in the UK. Patients were interviewed using a series of standardised clinical rating scales at baseline, 12, 24 and 36 months. Data relating to VHs were collected using the North-East Visual Hallucinations Interview. Prevalence rates for VHs at each assessment were recorded. Associations were determined using multiple regression analysis. RESULTS: Cross-sectional prevalence rates for VHs at baseline, 12, 24 and 36 months indicated VHs in approximately 50% of patients. A cumulative frequency of 82.7% of cases at the end of the study period exhibited VHs. The incidence rate for VHs was 457 cases per 1000 population. Longer disease duration, greater impairment in activities of daily living and higher rates of anxiety were most commonly associated with VHs. No factors predictive of VHs could be ascertained. CONCLUSIONS: When examined longitudinally, VHs affect more patients than is commonly assumed in cross-sectional prevalence studies. Clinicians should routinely screen for VHs throughout the disease course. Disease duration, impairment in activities of daily living and anxiety presented as co-morbidities associated with VHs in PD, and therefore those presenting with VHs should be screened for anxiety disorder and vice versa. Copyright © 2012 John Wiley & Sons, Ltd.International Journal of Geriatric Psychiatry 06/2013; 28(6). DOI:10.1002/gps.3869 · 3.09 Impact Factor
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ABSTRACT: REM sleep behaviour disorder (RBD) is a REM sleep-related parasomnia which may be considered a "dissociated state of wakefulness and sleep", given that conflicting elements of REM sleep (dreaming) and of wakefulness (sustained muscle tone and movements) coexist during the episodes, leading to motor and behavioural manifestations reminiscent of an enacted dream. RBD has been reported in association with α-synucleinopathies: around a third of patients with Parkinson's disease (PD) have full-blown RBD. Recent data indicate that PD patients with RBD are more prone to hallucinations than PD patients without this parasomnia. However it is still not clear why RBD in PD is associated with an increased prevalence of VHs. Data exist which suggest that visual hallucinations in PD may be the result of untimely intrusions of REM visual imagery into wakefulness. RBD, which is characterised by a REM sleep dissociation pattern, might be a condition that particularly favours such intrusions. However, other hypotheses may be advanced. In fact, deficits in attentional, executive, visuoperceptual and visuospatial abilities have been documented in RBD and found to occur far more frequently in PD with RBD than in PD without RBD. Neuropsychological deficits involving visual perception and attentional processes are thought to play an important role in the pathophysiology of VHs. On this basis, RBD in PD could be viewed as a contributory risk factor for VHs.Consciousness and Cognition 11/2010; 20(4):1021-6. DOI:10.1016/j.concog.2010.10.009 · 2.31 Impact Factor
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ABSTRACT: Impaired visual processing may play a role in the pathophysiology of visual hallucinations in Parkinson's disease. In order to study involved neuronal circuitry, we assessed cerebral activation patterns both before and during recognition of gradually revealed images in Parkinson's disease patients with visual hallucinations (PDwithVHs), Parkinson's disease patients without visual hallucinations (PDnonVHs) and healthy controls. We hypothesized that, before image recognition, PDwithVHs would show reduced bottom-up visual activation in occipital-temporal areas and increased (pre)frontal activation, reflecting increased top-down demand. Overshoot of the latter has been proposed to play a role in generating visual hallucinations. Nine non-demented PDwithVHs, 14 PDnonVHs and 13 healthy controls were scanned on a 3 Tesla magnetic resonance imaging scanner. Static images of animals and objects gradually appearing out of random visual noise were used in an event-related design paradigm. Analyses were time-locked on the moment of image recognition, indicated by the subjects' button-press. Subjects were asked to press an additional button on a colour-changing fixation dot, to keep attention and motor action constant and to assess reaction times. Data pre-processing and statistical analysis were performed with statistical parametric mapping-5 software. Bilateral activation of the fusiform and lingual gyri was seen during image recognition in all groups (P < 0.001). Several seconds before image recognition, PDwithVHs showed reduced activation of the lateral occipital cortex, compared with both PDnonVHs and healthy controls. In addition, reduced activation of extrastriate temporal visual cortices was seen just before image recognition in PDwithVHs. The association between increased vulnerability for visual hallucinations in Parkinson's disease and impaired visual object processing in occipital and temporal extrastriate visual cortices supported the hypothesis of impaired bottom-up visual processing in PDwithVHs. Support for the hypothesized increased top-down frontal activation was not obtained. The finding of activation reductions in ventral/lateral visual association cortices in PDwithVHs before image recognition further helps to explain functional mechanisms underlying visual hallucinations in Parkinson's disease.Brain 09/2009; 132(Pt 11):2980-93. DOI:10.1093/brain/awp223 · 10.23 Impact Factor