Patient's perception: shorter and more severe prodromal phase in GBA-associated PD

BACKGROUND

Prevalence and time of occurrence of prodromal symptoms of Parkinson's disease (PD) in relation to the onset of classical motor manifestation varies between patients. Possible modifying factors might be different genetic architectures predisposing to varying burden of manifestations.

OBJECTIVES

To characterize the prodromal phase in PD patients with heterozygous mutations in the GBA gene compared to PD patients without GBA mutation.

METHODS

In a retrospective design, 151 participants [47 PD patients carrying a GBA mutation (PD_GBA ), 52 idiopathic PD patients (PD_idiopathic ), 52 healthy elderly (CON)] underwent a validated structured interview designed to assess prevalence and time of occurrence of prodromal symptoms.

RESULTS

PD_GBA showed a higher prevalence of prodromal symptoms and almost simultaneous occurrence of non-motor and early motor symptoms shortly before PD diagnosis whereas PD_idiopathic reported a longer prodromal phase starting with non-motor symptoms.

CONCLUSION

The short and severe prodromal phase in PD_GBA might call for shorter assessment intervals in yet premanifest GBA mutation carriers.

Prodromal features for Parkinson's disease--baseline data from the TREND study

BACKGROUND AND PURPOSE

A number of non-motor features are known to precede motor manifestations of Parkinson's disease (PD). They are supposed to already represent the prodromal neurodegenerative state in those who later develop PD and are thus called prodromal markers. In this study, three prodromal markers, depression, rapid eye movement behaviour disorder (RBD) and hyposmia, were selected and were related to other prodromal features in elderly individuals without PD.

METHODS

From the Tübinger Evaluation of Risk Factors for Early Detection of Neurodegeneration (TREND) study, 698 healthy individuals aged 50-80 years reporting one or more of the selected prodromal markers (SPMs), but without neurodegenerative disorders, were evaluated and classified according to the status of prodromal markers. Other prodromal PD-related features were assessed with a 23-item questionnaire and compared between participants with and without the three SPMs.

RESULTS

Individuals with the SPMs for PD endorsed more of the additional possible prodromal features of PD than those without; of 23 possible prodromal features, the median number identified amongst participants with no SPMs was two, compared with four with one marker, five with two and seven with three (P < 0.001). Regarding individual SPMs, participants with depression and RBD endorsed five of 23 markers, compared with three for those with hyposmia (P = 0.001). There was no significant increase in the number of prodromal features amongst those with two SPMs compared with those with only one marker.

CONCLUSIONS

Individuals with the SPMs for PD report a higher prevalence of other prodromal PD symptoms. This may indicate that these markers can identify individuals at risk for PD.

The PRIPS study: screening battery for subjects at risk for Parkinson's disease

BACKGROUND AND PURPOSE

Screening batteries to narrow down a target-at-risk population are essential for trials testing neuroprotective compounds aiming to delay or prevent onset of Parkinson's disease (PD).

METHODS

The PRIPS study focuses on early detection of incident PD in 1847 at baseline PD-free subjects, and assessed age, male gender, positive family history, hyposmia, subtle motor impairment and enlarged substantia nigra hyperechogenicity (SN+).

RESULTS

After 3 years follow-up 11 subjects had developed PD. In this analysis of the secondary outcome parameters, sensitivity and specificity of baseline markers for incident PD were calculated in 1352 subjects with complete datasets (10 PD patients). The best approach for prediction of incident PD comprised three steps: (i) prescreening for age, (ii) primary screening for positive family history and/or hyposmia, and (iii) secondary screening for SN+.

CONCLUSION

With this approach, one out of 16 positively screened participants developed PD compared to one out of 135 in the original cohort. This corresponds to a sensitivity of 80.0%, a specificity of 90.6% and a positive predictive value of 6.1%. These values are higher than for any single screening instrument but still too low for a feasible and cost-effective screening strategy which might require longer follow-up intervals and application of additional instruments.

Cross-sectional study discloses a positive family history for Parkinson’s disease and male gender as epidemiological risk factors for substantia nigra hyperechogenicity

Hyperechogenicity of the substantia nigra (SN) has been proposed to be a typical finding in Parkinson's disease (PD) and a marker of vulnerability to nigrostriatal dysfunction in healthy subjects. This large cross-sectional study including 1120 subjects older than 50 years without any signs of PD was performed to evaluate the association of SN hyperechogenicity and other proposed epidemiological risk factors for PD. Among all variables assessed only family history of PD and male gender proved to be significantly associated with SN hyperechogenicity, indicating a genetic predisposition for the ultrasound marker.