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

<table class="table-group" id="tab7"><tr><td><table class="table"><tr><td class="thead-hr" colspan="3"><hr/></td></tr><tr class="thead"><td class="align_left"></td><td class="align_center">Letter fluency</td><td class="align_center">Category fluency</td></tr><tr><td class="thead-hr" colspan="3"><hr/></td></tr><tr><td class="align_left">Words: 0–15 s</td><td class="align_center"><span style="width: 22.2026ptpx;"><svg height="10.335pt" id="M47" style="vertical-align:-0.2325001pt" version="1.1" viewbox="-0.0498162 -10.1025 22.2026 10.335" width="22.2026pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z" id="g113-47"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="228" vert-adv-y="228"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,2.964,0)"><path d="M152 515H407L439 613L433 623H115L70 303C91 310 134 322 179 322C270 322 327 264 327 174C327 100 297 45 235 45C178 45 130 84 106 106C93 117 82 120 70 112C53 99 38 76 38 61S43 36 63 20C84 2 126 -12 166 -12C226 -11 297 15 354 56C424 105 455 164 455 226C455 312 382 394 254 394C228 394 175 380 125 362L152 515Z" id="g13-51"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,9.464,0)"><path d="M253 635C100 635 24 509 24 420C24 314 97 231 217 231C234 231 251 236 275 248L324 274C298 154 195 47 47 21L53 -15C98 -14 184 2 223 18C365 74 471 201 471 382C471 519 398 635 253 635ZM232 595C310 595 335 485 335 387C335 365 334 340 330 313C316 307 300 300 275 300C202 300 156 374 156 460C156 525 178 595 232 595Z" id="g13-55"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,16.024,-5.741)"><path d="M486 158C486 177 478 202 466 220C413 228 386 236 336 262C386 288 413 297 466 304C478 323 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103 114 103S58 78 58 46C58 11 82 -12 113 -12Z" id="g113-47"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="228" vert-adv-y="228"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,2.964,0)"><path d="M152 515H407L439 613L433 623H115L70 303C91 310 134 322 179 322C270 322 327 264 327 174C327 100 297 45 235 45C178 45 130 84 106 106C93 117 82 120 70 112C53 99 38 76 38 61S43 36 63 20C84 2 126 -12 166 -12C226 -11 297 15 354 56C424 105 455 164 455 226C455 312 382 394 254 394C228 394 175 380 125 362L152 515Z" id="g13-51"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,9.464,0)"><path d="M262 635C141 635 57 556 57 461C57 387 108 338 166 306C137 289 92 261 74 245C56 228 32 204 32 157C32 55 118 -12 249 -12C346 -12 472 51 472 178C472 266 409 313 339 351C378 376 396 392 412 406C435 428 445 453 445 480C445 569 371 635 262 635ZM246 595C286 595 338 561 338 475C338 417 318 386 301 370C224 406 172 439 172 507C172 549 199 595 246 595ZM260 28C210 28 152 72 152 169C152 221 175 265 204 287C301 235 350 209 351 137C352 71 315 28 260 28Z" id="g13-54"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,16.024,-5.741)"><path d="M486 158C486 177 478 202 466 220C413 228 386 236 336 262C386 288 413 297 466 304C478 323 486 347 485 366C470 376 444 381 422 380C389 338 368 319 321 288C323 345 329 372 349 422C339 442 322 461 305 470C289 461 271 442 262 422C281 372 287 345 290 288C243 319 222 338 189 380C167 381 142 376 125 366C125 347 133 322 145 304C198 296 225 288 275 262C225 236 198 227 145 220C133 201 125 177 126 158C141 148 167 143 189 144C222 186 243 205 290 236C288 179 282 152 262 102C272 82 289 63 306 54C322 63 340 82 350 102C330 152 324 179 321 236C368 205 390 186 422 144C444 143 470 148 486 158Z" id="g50-43"></path><glyph.data ascent="3443" descent="-2856" horiz-adv-x="611" vert-adv-y="611"></glyph.data></g></svg></span></td></tr><tr><td class="align_left">Words: 16–60 s</td><td class="align_center"><span style="width: 22.2026ptpx;"><svg height="10.335pt" id="M49" style="vertical-align:-0.2325001pt" version="1.1" viewbox="-0.0498162 -10.1025 22.2026 10.335" width="22.2026pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z" id="g113-47"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="228" vert-adv-y="228"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,2.964,0)"><path d="M476 623H66C59 580 53 527 39 449H74C102 508 110 515 178 515H391C305 352 205 176 87 1L95 -12L198 0C289 205 390 410 485 611L476 623Z" id="g13-53"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,9.464,0)"><path d="M152 515H407L439 613L433 623H115L70 303C91 310 134 322 179 322C270 322 327 264 327 174C327 100 297 45 235 45C178 45 130 84 106 106C93 117 82 120 70 112C53 99 38 76 38 61S43 36 63 20C84 2 126 -12 166 -12C226 -11 297 15 354 56C424 105 455 164 455 226C455 312 382 394 254 394C228 394 175 380 125 362L152 515Z" id="g13-51"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,16.024,-5.741)"><path d="M486 158C486 177 478 202 466 220C413 228 386 236 336 262C386 288 413 297 466 304C478 323 486 347 485 366C470 376 444 381 422 380C389 338 368 319 321 288C323 345 329 372 349 422C339 442 322 461 305 470C289 461 271 442 262 422C281 372 287 345 290 288C243 319 222 338 189 380C167 381 142 376 125 366C125 347 133 322 145 304C198 296 225 288 275 262C225 236 198 227 145 220C133 201 125 177 126 158C141 148 167 143 189 144C222 186 243 205 290 236C288 179 282 152 262 102C272 82 289 63 306 54C322 63 340 82 350 102C330 152 324 179 321 236C368 205 390 186 422 144C444 143 470 148 486 158Z" id="g50-43"></path><glyph.data ascent="3443" descent="-2856" horiz-adv-x="611" vert-adv-y="611"></glyph.data></g></svg></span></td><td class="align_center"><span style="width: 22.2026ptpx;"><svg height="10.335pt" id="M50" style="vertical-align:-0.2325001pt" version="1.1" viewbox="-0.0498162 -10.1025 22.2026 10.335" width="22.2026pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M113 -12C146 -12 170 11 170 46C170 78 146 103 114 103S58 78 58 46C58 11 82 -12 113 -12Z" id="g113-47"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="228" vert-adv-y="228"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,2.964,0)"><path d="M476 623H66C59 580 53 527 39 449H74C102 508 110 515 178 515H391C305 352 205 176 87 1L95 -12L198 0C289 205 390 410 485 611L476 623Z" id="g13-53"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.013,0,0,-0.013,9.464,0)"><path d="M486 174V231H396V629H324C229 512 123 368 15 215V174H269V116C269 55 264 41 179 34V0H477V34C403 41 396 51 396 112V174H486ZM269 231H90C155 335 219 427 267 493H269V231Z" id="g13-50"></path><glyph.data ascent="1024" descent="-360" horiz-adv-x="500" vert-adv-y="500"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,16.024,-5.741)"><path d="M486 158C486 177 478 202 466 220C413 228 386 236 336 262C386 288 413 297 466 304C478 323 486 347 485 366C470 376 444 381 422 380C389 338 368 319 321 288C323 345 329 372 349 422C339 442 322 461 305 470C289 461 271 442 262 422C281 372 287 345 290 288C243 319 222 338 189 380C167 381 142 376 125 366C125 347 133 322 145 304C198 296 225 288 275 262C225 236 198 227 145 220C133 201 125 177 126 158C141 148 167 143 189 144C222 186 243 205 290 236C288 179 282 152 262 102C272 82 289 63 306 54C322 63 340 82 350 102C330 152 324 179 321 236C368 205 390 186 422 144C444 143 470 148 486 158Z" id="g50-43"></path><glyph.data ascent="3443" descent="-2856" horiz-adv-x="611" vert-adv-y="611"></glyph.data></g></svg></span></td></tr><tr><td class="align_left">Cluster size</td><td class="align_center">−.15</td><td class="align_center">.32</td></tr><tr><td class="align_left">Number of switches</td><td class="align_center">.27</td><td class="align_center">.25</td></tr><tr><td class="align_left">Total errors</td><td class="align_center">.12</td><td class="align_center">−.17</td></tr><tr class="table-tr"><td colspan="3"><hr class="tbody-hr"/></td></tr></table></td></tr><tr class="table-fn"><td><svg height="13.532pt" id="M51" style="vertical-align:-3.4295pt" version="1.1" viewbox="-0.0498162 -10.1025 44.3418 13.532" width="44.3418pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.0091,0,0,-0.0091,0,-5.741)"><path d="M486 158C486 177 478 202 466 220C413 228 386 236 336 262C386 288 413 297 466 304C478 323 486 347 485 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Pearson correlations between decline in verbal fluency and fluency characteristics after DBS.

Behavioural Neurology

tab7

Table 7

Table 7: Apathy and Reduced Speed of Processing Underlie Decline in Verbal Fluency following DBS 