Midbrain area for differentiating Parkinson's disease from progressive supranuclear palsy.

OBJECTIVES

We aimed to investigate the values of midbrain area in diagnosing Parkinson's Disease (PD) and progressive supranuclear palsy (PSP) by using transcranial sonography (TCS). Disease duration effect on brain sonographic findings could decrease the accuracy of TCS in PD and PSP patients. We reduced the disease duration effect on sonographic differences found between PD and PSP patients by using multivariate analysis.

PATIENTS AND METHODS

Patients with clinical diagnosis of PSP and PD were recruited. We used SonoSite Edge II Ultrasound system to measure midbrain area, diameter of third ventricle and substantia nigra echogenicity. Diagnostic value of each measured area in sonography was estimated regarding its power for diagnosing PD or PSP. Independent sample t-test, Regression analysis and receiver operating characteristic (ROC) curve were performed using SPSS software.

RESULTS

Of 35 patients, 18 were PD and 17 PSP cases. The mean midbrain area was 4.86 ± 0.71cm in PD patients and 3.61 ± 0.85cm in those with PSP (P < 0.005). Regression for reducing the effect of disease duration on midbrain area variances between patients with PD and PSP revealed a significant P value (P < 0.005, Adjusted R = 0.36). The sensitivity and specificity of midbrain area in diagnosing PD were 83.3% and 70.6% respectively. The sensitivity of the third ventricle size in diagnosing PSP was 82% although its specificity was 62%.

CONCLUSION

Midbrain area in patients with PD was wider than those with PSP that was not affected by disease duration. Midbrain area was the most accurate index for diagnosing PD by TCS although third ventricle size was the most sensitive one for diagnosing PSP.