Enlarged Substantia Nigra Hyperechogenicity and Risk for Parkinson Disease: A 37-Month 3-Center Study of 1847 Older Persons

Berg D, Seppi K, Behnke S, et al

Arch Neurol. 2011;68:932-937

Study Background

If patients with subclinical pathologic features of Parkinson disease (PD) could be identified before they developed symptoms, it could open a window for early neuroprotective intervention.

The substantia nigra (SN) of the midbrain is involved early in the pathogenesis and course of PD, and transcranial sonography has shown that 90% of patients with PD (but only about 10% of elderly control patients) have SN hyperechogenicity. However, it was not previously determined whether SN hyperechogenicity could predict subsequent development of PD in still-healthy persons.

Study Summary

This longitudinal, 3-center observational study prospectively evaluated the association between baseline SN echogenic status and the 3-year incidence of PD in 1847 healthy individuals who were at least 50 years of age. Participants gave a full medical history, had a neurological examination and transcranial sonography, and 1535 of them had a follow-up evaluation. The primary study endpoint was incidence of new-onset PD in relation to transcranial sonography status at baseline.

During a mean observation period of 37 months, there were 11 cases of incident PD. SN hyperechogenicity occurred in 18.7% of the total cohort in whom temporal bone window was sufficient for evaluation, in 17.1% of those who did not develop PD, and in 80% of those who did develop PD. However, only 3.1% of those with SN hyperechogenicity developed PD. Compared with participants who had SN normoechogenicity,

Viewpoint

This prospective study is the first to show a markedly increased risk for PD in elderly persons with SN hyperechogenicity. Limitations of this study include relatively short follow-up period, selection bias, and differing recruitment strategies and ultrasonographic equipment among centers. Nonetheless, transcranial sonography of the midbrain may be promising as a screening procedure to detect imminent PD in appropriate high-risk population groups, particularly because it is noninvasive, inexpensive, and quick and easy to perform by properly trained examiners.

ABSTRACT:

Enlarged substantia nigra hyperechogenicity and risk for Parkinson disease: a 37-month 3-center study of 1847 older persons.

Arch Neurol.  2011; 68(7):932-7 (ISSN: 1538-3687)

Berg D; Seppi K; Behnke S; Liepelt I; Schweitzer K; Stockner H; Wollenweber F; Gaenslen A; Mahlknecht P; Spiegel J; Godau J; Huber H; Srulijes K; Kiechl S; Bentele M; Gasperi A; Schubert T; Hiry T; Probst M; Schneider V; Klenk J; Sawires M; Willeit J; Maetzler W; Fassbender K; Gasser T; Poewe W
Department of Neurodegeneration, Hertie Institute for Clinical Brain Research and German Center of Neurodegenerative Diseases, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany. daniela.berg@uni-tuebingen.de

OBJECTIVE: To evaluate whether enlarged substantia nigra hyperechogenicity (SN+) is associated with an increased risk for Parkinson disease (PD) in a healthy elderly population.

DESIGN: Longitudinal 3-center observational study with 37 months of prospective follow-up.

SETTING: Individuals 50 years or older without evidence of PD or any other neurodegenerative disease.

PARTICIPANTS: Of 1847 participants who underwent a full medical history, neurological assessment, and transcranial sonography at baseline, 1535 could undergo reassessment.

MAIN OUTCOME MEASURE: Incidence of new-onset PD in relation to baseline transcranial sonography status.

RESULTS: There were 11 cases of incident PD during the follow-up period. In participants with SN+ at baseline, the relative risk for incident PD was 17.37 (95% confidence interval, 3.71-81.34) times higher compared with normoechogenic participants.

CONCLUSIONS: In this prospective study, we demonstrate for the first time a highly increased risk for PD in elderly individuals with SN+. Transcranial sonography of the midbrain may therefore be a promising primary screening procedure to define a risk population for imminent PD.