Table 1.

Characteristics of subjects with Parkinson’s disease (PD) and bilateral deep brain stimulation of the subthalamic nuclei

SID	AGE	PD YRS	DBS MOS	UPDRS SPEECH	LEVO	L.AMP	R.AMP
103	54	14	44	1	250	3.2	2.8
104	57	17	27	2	400	3.0	3.0
106	59	17	9	3	600	3.0	3.0
107	62	17	2	2	600	2.5	2.6
108	61	11	12	1	600	2.8	2.8
109	49	9	6	1	300	2.6	2.5
110	62	11	56	2	600	3.0	3.3
111	56	11	37	1	400	3.0	3.0

KEY: SID = subject identifier; AGE = in years; PD YRS = duration of PD; DBS MOS = duration of DBS therapy in months; UPDRS SPEECH = the speech rating in the UPDRS motor evaluation; LEVO = daily levodopa dose in mg; L.AMP =  amplitude of stimulation on the left side; R.AMP =  amplitude of stimulation on the right side. All stimulation was at 185 Hz with a pulse width of 60 micro seconds. The UPDRS SPEECH ratings are 0 (normal), 1 (slight loss of expression, diction, and/or voice, 2 (monotone, slurred, but understandable), 3 (marked impairment but difficult to understand), and 4 (unintelligible).