Parkinson's disease disrupts the ability to initiate and apply episodic foresight

Behavioral disorders in Parkinson disease: current view

Patients with Parkinson disease (PD) frequently experience several behavioral symptoms, such as anxiety, apathy, irritability, agitation, impulsive control and obsessive-compulsive or REM sleep behavior disorders, which can cause severe psychosocial problems and impair quality of life. Occurring in 30-70% of PD patients, these symptoms can manifest at early stages of the disease, sometimes even before the appearance of classic motor symptoms, while others can develop later. Behavioral changes in PD show distinct patterns of brain atrophy, dopaminergic and serotonergic deterioration, altered neuronal connectivity in frontostriatal, corticolimbic, default mode and other networks due to a cascade linking molecular pathologies and deficits in multiple behavior domains. The changes suggest a multi-system neurodegenerative process in the context of a specific α-synucleinopathy inducing a variety of biochemical and functional changes, the neurobiological basis and clinical relevance of which await further elucidation. This paper is intended to review the recent literature with focus on the main behavioral disturbances in PD patients, their epidemiology, clinical features, risk factors, animal models, neuroimaging findings, pathophysiological backgrounds, and treatment options of these deleterious lesions.

Episodic foresight is impaired following acute alcohol intoxication

BACKGROUND

Alcohol intoxication disrupts many aspects of cognition, including the generation of phenomenological characteristics of future events (a component of episodic foresight), and the execution of directed preparatory behaviours (a component of prospective memory). However, no study has tested whether alcohol intoxication is also associated with deficits engaging episodic foresight to guide future-directed behaviour.

AIMS

This study was designed to provide the first test of how alcohol intoxication influences the functional application of episodic foresight. The secondary aim was to establish the degree to which any observed episodic foresight difficulties associated with alcohol use might reflect broader problems in retrospective memory and executive control. Sex differences were also examined.

METHODS

Healthy adult social drinkers randomly received either a moderate dose of 0.6 g/kg alcohol (n = 61) or a matched placebo drink (n = 63) and then completed a validated measure that met strict criteria for assessing the functional application of episodic foresight as well as a broader cognitive test battery.

RESULTS

Relative to the placebo condition, episodic foresight was impaired by acute alcohol consumption, with this impairment related to poorer retrospective memory, but not executive control. The negative effects of alcohol intoxication on episodic foresight did not differ as a function of sex.

CONCLUSIONS

Even a moderate level of intoxication impairs the ability to use episodic foresight in a functionally adaptive way. These findings have implications for understanding many of the maladaptive behaviours that are often associated with acute alcohol use.

The antecedents and consequences of stereotype threat in Parkinson's disease

OBJECTIVE

The aim of this study was to examine what factors make people with Parkinson's disease more susceptible to stereotype threat (i.e., the concern of being evaluated in line with negative group-based stereotypes) and the clinical consequences of this.

METHOD

Forty-nine people with Parkinson's disease completed a measure of stereotype threat, as well as measures that indexed potential antecedents and clinical consequences of stereotype threat.

RESULTS

Younger age and greater communication difficulties emerged as significant predictors of stereotype threat. Higher stereotype threat was also associated with increased emotional distress.

CONCLUSIONS

These findings are an important first step in understanding stereotype threat in Parkinson's disease and may help to guide the development of intervention and educational efforts aimed at countering its effects.

Affective forecasting in Parkinson's disease

OBJECTIVES

While emotional responses experienced in-the-moment appear to remain intact in Parkinson's disease (PD), no study has tested whether this extends to the prediction of future emotional responses. The present study aimed to provide the first assessment of affective forecasting capacity in this cohort.

METHODS

A positively and negatively valenced affective forecasting task and broader clinical battery were completed by a PD group (ns = 28 and 37, respectively) and a demographically matched neurotypical control group (ns = 38 and 39, respectively).

RESULTS

No group differences emerged on the two tasks, with the two groups underestimating their level of happiness and overestimating their level of negative affect to a similar degree. Affective forecasting error scores were unrelated to clinical characteristics.

CONCLUSIONS

Given that affective forecasting relies on self-projection into the future, a skill shown to often be disrupted in this cohort, impairments were expected. However, this study provides initial evidence that this may not be the case. These findings are potentially important given that how we think about and envisage the future affectively is a major determinant of goal-directed behavior. Further work is now needed to establish whether these findings are robust and generalize to other types of affective stimuli.