Table 3.

Controlled studies assessing cognitive change in PD patients after DBS.

Author, year	N of DBS patients	F/u (mo)	Lead location	Status of stimulation/medication at cognitive assessment	Cognitive performance(s) improved in DBS group	Cognitive performance(s) worsened in DBS group	Cognitive performance(s) not different between DBS and control group
Castelli et al., 2010 [39]	27	12	STN	ON/ON	None	L	E, A/C, M, L
Cilia et al., 2007 [16]	20	12	STN	ON/ON	None	L	GC, L, E, A/C
De Gaspari et al., 2006 [21]	12	12	STN	ON/ON	None	L	GC, E, L
Gironell et al., 2003 [36]	8	6	STN	ON/ON	None	None	L, E, A/C, M, V, PS
Hilker et al., 2004 [37]	8	4	STN	ON/-	M	None	GC, E, L, A/C, M, V
Moretti et al., 2003 [46]	9	12	STN	ON/ON	L	L, E	E, L, A/C, M, V
Morrison et al., 2004 [38]	17	3	STN	ON and OFF/OFF	None	None	L, A/C, M, E, V
Rukmini Mridula et al., 2015 [48]	50	23a	STN	ON/ON	None	None	GC, A/C
Phillips et al., 2012 [49]	11	13.8a	STN	ON and OFF/ON and OFF	None	None	L
Rothlind et al., 2015 [47]	281	6	STN n = 84 and GPI n = 80	ON/ON	None	A/C, E, PS, see text	A/C, E, L, M, PS
Sáez-Zea et al., 2012 [44]	9	6	STN	ON/ON	None	None	A, M, V, E, L, A/C
Smeding et al., 2011 [33]	105	12	STN	ON/ON	None	GC, E, L, V, M, A/C	L, A/C
Smeding et al., 2006 [43]	99	6	STN	ON/ON	None	L, A/C	L, M, V, A/C
Whelan et al., 2003 [24]	5	3	STN	ON/ON	L	L	None
Williams et al., 2011 [40]	19	24	STN	ON/ON	None	None	GC, M, E, A/C, L, V, PS
Witt et al., 2008 [42]	60	6	STN	ON/ON	None	A/C	GC, E, L, A/C
Witt et al., 2013 [41]	31	6	STN	ON/ON	None	None	GC, A/C, L
York et al., 2008 [17]	23	6	STN	ON/ON	None	M	GC, E, A/C, M, L, V, PS
Zangaglia et al., 2009 [45]	32	36	STN	ON/ON	None	L	GC, M, E, A/C
Zangaglia et al., 2012 [32]	30	96	STN	ON/ON	None	L	GC, M, E, A/C

PD: Parkinson's disease; STN: subthalamic nucleus; N: number; mo: months; A/C: attention/concentration; E: executive; GC: global cognition; L: language; M: memory; PS: psychomotor/processing speed; V: visual. ^amean. Note. Multiple tests were performed for each domain in each study, and often a few of these showed a difference while other tests assessing the same domain did not. This explains why the same domain might appear more than once and under different results for the same study. Adapted from Mehanna [11] with permission from the author.