Objective: To investigate structural abnormality of the substantia nigra (SN) in methamphetamine users using transcranial sonography (TCS).

Background: Epidemiologic studies suggest that chronic use of methamphetamine is associated with an increased risk to develop Parkinson´s disease (PD). Repeated exposure to methamphetamine was shown to damage specifically nigral dopaminergic neurons in animal studies. The abnormal spatial extension of the echogenic substantia nigra assessed by transcranial sonography (TCS) is considered a marker for abnormality of the dopaminergic nigrostriatal system and can be found in up to 90% of PD patients vs. 10% in matched healthy controls.

Methods: TCS of the SN was performed on 61 participants (age 28±5y;17 female) with a history of methamphetamine use and 58 controls (age 27±6y;21female). The echogenic SN-area was assessed on both sides to evaluate the average size of the left and right SN (SN(L,R)). A SN-area of more than 24 mm2 was considered abnormal (SN+). Prevalence of an abnormal spatial extension of the SN as well as the average size of the SN(L,R) were evaluated.

Results: SN+ was found in 21 out of 61 (34%) methamphetamine users and in 5 out of 57 (9%) control subjects (Chi²-Test: p=0.001). Average echogenic size of the SN was larger in methamphetamine users (21.7±0.9mm²) compared with controls (16.1±0.7mm², t-test: p<0.001). In addition, we found a positive correlation of total lifetime methamphetamine intake with SN(L,R) in the methamphetamine users group (r=0.281, p=0.029).

Conclusions: Our data suggest an increased prevalence of nigrostriatal abnormality in subjects with a history of methamphetamine use. The association of methamphetamine dose and magnitude of echogenic changes in the SN may point to a toxic mechanism, although adaptive changes cannot be excluded.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/frequency-of-echogenic-abnormality-of-the-substantia-nigra-is-increased-in-methamphetamine-users/