Effects of contact location and voltage amplitude on speech and movement in bilateral subthalamic nucleus deep brain stimulation

✍ Scribed by Elina Tripoliti; Ludvic Zrinzo; Irene Martinez-Torres; Stephen Tisch; Eleanor Frost; Ellie Borrell; Marwan I. Hariz; Patricia Limousin

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 154 KB
• Volume: 23
• Category: Article
• ISSN: 0885-3185
• DOI: 10.1002/mds.22296

✦ Synopsis

Abstract

Subthalamic nucleus deep brain stimulation (STN‐DBS) is particularly effective in improving limb symptoms in Parkinson's disease. However, speech shows a variable response. Contact site and amplitude of stimulation have been suggested as possible factors influencing speech. In this double blind study, we assessed 14 patients post bilateral STN‐DBS, without medication. Six conditions were studied in random order as follows: stimulation inside the STN at low voltage (2 V) and at high voltage (4 V); above the STN at 2 V and at 4 V, at usual clinical parameters, and off‐stimulation. The site of stimulation was defined on the postoperative stereotactic MRI data. Speech protocol consisted of the assessment of intelligibility of the dysarthric speech, maximum sustained phonation, and a 1‐minute monologue. Movement was assessed using the UPDRS‐III. Stimulation at 4 V significantly reduced the speech intelligibility (P = 0.004) independently from the site of stimulation. Stimulation at 4 V significantly improved the motor function. Stimulation inside the nucleus was significantly more effective than outside the nucleus (P = 0.0006). The significant improvement in movement coupled with significant deterioration in speech intelligibility when patients are stimulated inside the nucleus at high voltage indicates a critical role for electrical stimulation parameters in speech motor control. © 2008 Movement Disorder Society