Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS

Table 5

Correlations between decline in verbal fluency and changes in other measures after DBS.

	Letter fluency	Category fluency
AES	.15^a	.33^a
GNT	−.04^a	−.04^a
Vocabulary	−.32	−.45^a
Stroop	−.26^a	−.40^a
Hayling	−.50^b	−.47^b*
Brixton	−.09^a	−.20^a
TEA ECD	−.23^a	−.27^a
MCST-categories	−.16^b	−.08^b
TMT-B/A	.07^a	−.04^a
SS	−.32^a	−.53^a
DSC	.14^a	−.45^a

^aPearson’s r coefficient, ^bSpearman’s p coefficient, . AES: Apathy Evaluation Scale [67]; GNT: Graded Naming Test [69]; Vocabulary, WAIS-III [62]; Stroop [70]; Hayling: Hayling Sentence Completion Test [71]; Brixton: Brixton Spatial Anticipation Test [71]; TEA ECD: Test of Everyday Attention, Elevator Counting with Distraction [72]; MCST: Modified Card Sorting Test [73]; TMT: Trail Making Test [74]; SS: Symbol Search, WAIS-III [62]; DSC: Digit Symbol Coding, WAIS-III [62].