Lombard Effect on Speech Clarity in Patients with Parkinson Disease

Acoustic studies of Lombard speech shown that other articulatory changes occur beside the increase in loudness. Lombard speech in healthy speakers is characterized by decreased speaking rate, increased fundamental frequency range and vowel space. Recently, there has been increased interest in the effect of background noise on speakers with Parkinson Disease. Nineteen patients with Mild-to-Moderate Idiopathic PD and 19 age-and-sex matched healthy speakers were recruited to investigate these measures in quiet and Lombard conditions. Results showed an increase in loudness and F0 measures, and a decrease in speaking rate measures in both groups as a function of noise. The VS remains unchanged for both groups in the Lombard condition. The male speakers in both groups showed increased VS compared to their female counterparts. The Parkinsonian group showed a smaller VS area in both conditions. In particular, the PD patients with moderate severity showed centralized VS compared to the healthy participants. These findings suggest that Parkinsonians utilize neuromotor planning for speech production similar to normal speakers; however, it deteriorates as PD advances.