Personality characteristics and motor skills attributed to occupations in Parkinson disease

Can anxiety-like behavior and spatial memory predict the extremes of skilled walking performance in mice? An exploratory, preliminary study

Introduction

Skilled walking is influenced by memory, stress, and anxiety. While this is evident in cases of neurological disorders, memory, and anxiety traits may predict skilled walking performance even in normal functioning. Here, we address whether spatial memory and anxiety-like behavior can predict skilled walking performance in mice.

Methods

A cohort of 60 adult mice underwent a behavioral assessment including general exploration (open field), anxiety-like behavior (elevated plus maze), working and spatial memory (Y-maze and Barnes maze), and skilled walking performance (ladder walking test). Three groups were established based on their skilled walking performance: superior (SP, percentiles ≥75), regular (RP, percentiles 74-26), and inferior (IP, percentiles ≤25) performers.

Results

Animals from the SP and IP groups spent more time in the elevated plus maze closed arms compared to the RP group. With every second spent in the elevated plus maze closed arms, the probability of the animal exhibiting extreme percentiles in the ladder walking test increased by 1.4%. Moreover, animals that spent 219 s (73% of the total time of the test) or more in those arms were 4.67 times more likely to exhibit either higher or lower percentiles of skilled walking performance.

Discussion

We discuss and conclude anxiety traits may influence skilled walking performance in facility-reared mice.

Writers Are Common among Parkinson's Disease Patients: A Longitudinal Study

Parkinson's disease (PD) patients may have a specific personality profile, which includes being introvert, cautious and devoted to hard work. The evaluation of psychological characteristics must be evaluated according to methods for assessments of personality disorders. Such evaluations are often time-consuming and available only in research settings. The “parkinsonian trait” may be established early in life but may change with disease progression. To overcome this long interval before onset of PD questions on literary activities were included in the medical record. Three percent of PD patients could be defined as writers, significantly higher than observed in the general population. PD writers published their first books long before onset of disease. Being a writer is an extrovert trait meaning that the patient is prepared for criticism and publicity. We suggest that questions regarding personal activities prior to disease onset add valuable information on personality which differs significantly from traits observed later in the disease period.

Reduced workforce participation 5 years prior to first Parkinson's disease sick-leave

The importance of understanding the prodromal phase of Parkinson’s disease (PD) by systematic recording of prediagnostic symptoms and reductions in body functions has been highlighted. The aim of this study was to investigate whether persons later diagnosed with PD exhibit increased physician-certified sickness absence 1, 2, and 5 years prior to a first sick-leave episode attributed to PD. A case-control study was performed to analyze data from all nontrivial (exceeding 14 days) sick-leave episodes in Sweden between 2008 and 2014. The 537 incident PD sick-leave episodes were identified as PD sick-leave cases and compared to 537 sick-leave controls identified by matching age, sex, and date of the first day of the sick-leave episode. The total sickness absence and sickness absence due to musculoskeletal diagnoses were found to be increased among the PD sick-leave cases from 5 years prior to the first sick-leave episode ascribed to PD when compared to the controls. No differences between PD sick-leave cases and sick-leave controls were found with regard to mental and behavioral diagnoses. We conclude that the capacity to participate in working life is reduced already at the early prediagnostic stages of PD. This finding can be used as a basis for further research into the process of identifying individuals at risk for developing PD, particularly in combination with further investigation into biochemical, genetic, and imaging biomarkers.

A Swedish study shows that Parkinson’s disease (PD) patients had more sick-leave episodes in the years before diagnosis than matched controls not diagnosed with PD. There is growing evidence that prior PD diagnosis, patients experience a variety of nonmotor symptoms and subtle motor signs. Further understanding these symptoms could prompt earlier therapeutic intervention and increase the likelihood of slowing down or even halting disease progression. A study led by Jonathan Timpka at Lund University examined the sickness leave history of 537 workers 1, 2 and 5 years before a first sick-leave episode due to PD. These workers took more sick-leave due to musculoskeletal symptoms, but not due to mental or behavioral issues, than the control group. These findings highlight a potential effect of preclinical PD on patients’ ability to work.

Occupational stress and risk for Parkinson's disease: A nationwide cohort study

Background: Stress has been suggested as a contributing factor in the etiology of Parkinson's Disease (PD), but epidemiological evidence is sparse.

Objective: The objective of this study was to explore the association between occupational stress according to the job demands‐control model and the risk for PD.

Methods: We conducted a population‐based cohort study with 2,544,748 Swedes born 1920 to 1950 who had an occupation reported in the population and housing censuses in 1980 or, if missing, in 1970. Job demands and control were measured using a job‐exposure matrix. Incident PD cases were identified using Swedish national health registers from 1987 to 2010. Data were analyzed with Cox regression with age as the underlying time scale, adjusting for sex, education, and chronic obstructive pulmonary disease as a proxy for smoking.

Results: During a mean follow‐up time of 21.3 years, 21,544 incident PD cases were identified. High demands were associated with increased PD risk among men, most evident in men with high education. High control was associated with increased PD risk among the low educated. This association was more pronounced in women. High‐strain jobs (high demands and low control) was only associated with increased PDrisk among men with high education, whereas active jobs (high demands and high control) were associated with increased PD risk among men with low education.

Interpretation: High job demands appear to increase PD risk in men, especially in men with high education, whereas high job control increases PD risk among low educated, more strongly in women. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Onset and progression factors in Parkinson's disease: A systematic review

Current research has identified several factors thought to be associated with the onset and progression of Parkinson's Disease (PD); however, whether certain factors contribute to or are protective against PD remains unclear. As such, a systematic search of the literature was performed using variations of MeSH and keyword search terms to identify and summarize systematic reviews and primary studies pertaining to factors associated with the onset and progression of PD. Factors referred to both traditional risk factors and prodromal markers. The following databases were searched: MEDLINE, MEDLINE In-Process, EMBASE, PsycINFO, Scopus, Web of Science, Cochrane Database of Systematic Reviews, Cumulative Index to Nursing and Allied Health Literature (CINAHL), ProQuest Dissertations & Theses, AARP AgeLine, and PDGene. A quality assessment of included systematic reviews was completed using the validated Assessment of the Methodological Quality of Systematic Reviews (AMSTAR) tool. Data extraction targeted reported factors, risk estimates, and 95% confidence intervals (CI). Findings identified 11 systematic reviews of sufficient quality reporting factors for PD onset, and no systematic reviews reporting factors for PD progression. In addition, 93 primary articles were identified, of which, 89 articles addressed factors related to PD onset and 4 articles addressed factors related to the PD progression. Pesticide exposure, rural living, well-water drinking, and farming occupation were consistently found to be positively associated with the onset of PD. Moreover, family history and polymorphisms to key genes were also found to be positively associated with the onset of PD. Conversely, coffee consumption, cigarette smoking, and some polymorphisms were consistently found to be negatively associated with the onset of PD. Urate was the only identified factor linked to the progression of PD; it was mostly found to be negatively associated with PD. In sum, the evidence was systematically found and summarized in the literature pertaining to factors related to the onset and progression of PD.

Occupational Characteristics and Patterns as Risk Factors for Parkinson's Disease: A Case Control Study

BACKGROUND

Associations have been reported between the risk of Parkinson's disease (PD) and employment in certain fields. Most studies have focused on toxic exposures as potential causal explanations. However, PD also has been associated with personality characteristics that may influence occupational choices and patterns.

OBJECTIVE

This study evaluates the role of personality as indicated by occupational choices and employment patterns in the risk for PD.

METHODS

In-person interviews were conducted to assess occupational histories and early-adult personality indicators among 89 PD patients and 99 controls.

RESULTS

PD cases had fewer lifetime jobs than controls (mean for cases = 4.38 ± 2.20; mean for controls = 5.00 ± 2.26; p = 0.03). Among women, PD was positively associated with more complex work with people (OR = 1.45, 95% CI 1.12-1.89), representing a 95% increased risk for PD comparing women with the greatest complexity of work with those requiring the least complexity of work with people. Women PD cases also performed less complex work with things compared with controls (OR = 0.69 (95% CI 0.53-0.90)), translating into a 13-fold increased risk for PD among women whose work involved the least complex work with things compared with the most. The numbers of jobs and job types were associated with taking more activity risks as a young-adult (r = 0.19, p = 0.02; r = 0.26, p = 0.001, respectively).

CONCLUSIONS

Cases with PD held fewer lifetime jobs compared with controls. Occupational complexity was associated with the risk for PD among women, but not men. Further consideration of the possible influence of personality on occupational choices is warranted.

Occupational complexity and risk of Parkinson's disease

Background

The etiology of Parkinson's disease (PD) remains unclear, and environmental risk-factors such as occupation have attracted interest.

Objective

The goal was to investigate occupational complexity in relation to PD.

Methods

We conducted a population-based cohort study based on the Swedish Twin Registry that included 28,778 twins born between 1886 and 1950. We identified 433 PD cases during the study period. Data on occupation were collected from either the 1970 or 1980 Swedish census, and occupational complexity was assessed via a job exposure matrix. Cox proportional hazard regression analyses with age as the underlying time scale were used to assess PD risk as a function of the three domains of occupational complexity: data, people, and things. Sex and smoking were included as covariates. Analyses stratified by twin pair were conducted to test for confounding by familial factors.

Results

High occupational complexity with data and people was associated with increased risk overall (Hazard Ratio [HR] = 1.07, 95% confidence interval [CI] 1.02–1.14, and HR = 1.10, 95% CI 1.01–1.21, respectively), and in men (HR = 1.08, 95% CI 1.01–1.16, and HR = 1.15, 95% CI 1.03–1.28, respectively). Complexity with things was not associated with risk of PD. When the analyses were stratified by twin pair, the HRs for occupational complexity with data and people were attenuated in men.

Conclusions

High complexity of work with data and people is related to increased risk of PD, particularly in men. The attenuation of risk observed in the twin pair-stratified analyses suggests that the association may partly be explained by familial factors, such as inherited traits contributing to occupational selection or other factors shared by twins.

Comparison of personality characteristics in Parkinson disease patients with and without impulse control disorders and in healthy volunteers

OBJECTIVE

We aimed to assess personality characteristics in patients with Parkinson disease (PD) with and without impulse control disorders (ICD).

METHODS

We tested patients and controls with the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) scales that have expected high sensitivity to apparent addictive behavior. We recorded mean disease duration and mean levodopa dose in the PD groups.

RESULTS

Of the 46 PD patients, 13 had ICD: hypersexuality, binge eating, or dopamine dysregulation. The PD patients with ICD had a longer duration of disease (11 vs. 5 y) and were taking higher doses of levodopa (900 vs. 500 mg/d). They scored above the pathologic threshold in 4 domains of the MMPI-2 Clinical Scales and in 8 Clinical Subscales and Content Scales. The most significant abnormality was Alienation-Self and Others.

CONCLUSIONS

ICDs in the general population have similarities to disorders of substance addiction. In PD patients, some personality profiles could play a role in development of ICDs or dopamine dysregulation syndrome. The MMPI-2 may be a useful test for PD patients in general, and for detecting ICD in particular.