Effects of subthalamic stimulation on speech of consecutive patients with Parkinson disease.
Tripoliti E, Zrinzo L, Martinez-Torres I, Frost E, Pinto S, Foltynie T, Holl E, Petersen E, Roughton M, Hariz MI, Limousin P. Effects of subthalamic stimulation on speech of consecutive patients with Parkinson disease. , 2010 Nov 10
This article systematically looked at patients over time to evaluate the short and long-term effect(s) of deep brain stimulation of the subthalamic nucleus (DBS-STN) on speech in people with Parkinson’s disease (PWP) as there has been significant variability in the literature to its effect. It has been unclear in prior studies if the speech problems commonly seen are due to the surgery itself, disease severity, response to medication, spread of the current from the stimulator, patient specific characteristics (e.g. age, gender, etc.), or other unknown factors. The PWP who underwent DBS-STN in this study showed improved motor control, reduced medication usage, and variable speech effects. Although some patients had improvements in their speech after surgery, the majority did not (78% reported decline within 1 year of surgery). The decline in speech typically was observed over the three year time frame and remained even when the stimulator was turned off. The authors found that speech decline was related to a few factors, including the area within the STN in which the stimulator was placed, a pre-test motor score in the “on” medication state, and the higher amplitude of stimulation specifically in the left side of the brain (possibly due to the spreading of the current from the stimulator when it was on). Although DBS-STN improves motor symptoms of PD, this study confirms that this treatment could have deleterious effects on speech. Such research studies need to be conducted for this population so that PWP can make informed decisions about this surgical treatment option.