{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T06:18:12Z","timestamp":1769062692859,"version":"3.49.0"},"reference-count":28,"publisher":"Oxford University Press (OUP)","issue":"1","funder":[{"DOI":"10.13039\/100000002","name":"NIH","doi-asserted-by":"publisher","award":["R01 AG060987"],"award-info":[{"award-number":["R01 AG060987"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"NIH","doi-asserted-by":"publisher","award":["R01 AG060987"],"award-info":[{"award-number":["R01 AG060987"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"NIH","doi-asserted-by":"publisher","award":["MH115949"],"award-info":[{"award-number":["MH115949"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"NIH","doi-asserted-by":"publisher","award":["EB032820"],"award-info":[{"award-number":["EB032820"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"NIH","doi-asserted-by":"publisher","award":["P01 AG031720"],"award-info":[{"award-number":["P01 AG031720"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100006312","name":"BrightFocus Foundation","doi-asserted-by":"publisher","award":["A2021288S"],"award-info":[{"award-number":["A2021288S"]}],"id":[{"id":"10.13039\/100006312","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000049","name":"NIA","doi-asserted-by":"publisher","award":["1K23AG068384"],"award-info":[{"award-number":["1K23AG068384"]}],"id":[{"id":"10.13039\/100000049","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000957","name":"Alzheimer's Association","doi-asserted-by":"publisher","award":["2019-AACSF-643094"],"award-info":[{"award-number":["2019-AACSF-643094"]}],"id":[{"id":"10.13039\/100000957","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Veterans Health Administration","award":["IK2 CX002065"],"award-info":[{"award-number":["IK2 CX002065"]}]},{"name":"Veterans Health Administration","award":["IK2 CX002625"],"award-info":[{"award-number":["IK2 CX002625"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,1,17]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The Perturbation Complexity Index\u2014State Transitions (PCIST) measures the complexity of the brain\u2019s response to transcranial magnetic stimulation (TMS) using electroencephalography (EEG) and is sensitive to consciousness, such as minimally conscious states. Individuals with early-stage Alzheimer\u2019s disease (AD) show dysfunction of conscious processes, such as attention, working memory, episodic memory, and executive function, with relatively spared unconscious processes, such as procedural memory, operant conditioning, and priming. We sought to test the hypothesis that PCIST would be reduced in AD compared to healthy aging. We assessed 28 participants with AD and 27 healthy controls (HC), measuring cognition with the Montreal Cognitive Assessment (MoCA) and disease severity with the Clinical Dementia Rating scale\u2014Global (CDR-Global) and Sum of Boxes (CDR-SB). Results indicated lower PCIST in the AD group (M\u2009=\u200920.1) compared to controls (M\u2009=\u200928.2) across both the motor cortex (M1) and inferior parietal lobule (IPL) TMS stimulation sites, suggesting that PCIST may reflect the impaired conscious cognitive processes and functional capacity seen in AD. We therefore speculate that cortical dementias involve alterations in cortical complexity that may relate to deterioration of their conscious processes. This research opens the avenue for future studies in individuals with cortical dementia to examine the relationship between conscious processes, global measures of consciousness, and their underlying neuroanatomical correlates, in addition to enhancing our understanding of dementia and suggesting possible therapeutic strategies.<\/jats:p>","DOI":"10.1093\/nc\/niaf062","type":"journal-article","created":{"date-parts":[[2025,12,12]],"date-time":"2025-12-12T13:11:01Z","timestamp":1765545061000},"source":"Crossref","is-referenced-by-count":0,"title":["Evaluating Alzheimer's disease with the TMS-EEG perturbation complexity index"],"prefix":"10.1093","volume":"2026","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-7830-0780","authenticated-orcid":false,"given":"Brenna","family":"Hagan","sequence":"first","affiliation":[{"name":"Center for Translational Cognitive Neuroscience, VA Boston Healthcare System , 150 S. Huntington Ave, Boston, MA 02130 ,","place":["United States"]},{"name":"Alzheimer's Disease Research Center, Department of Neurology, Boston University, Chobanian and Avedisian School of Medicine , 72 E Concord St., Boston, MA 02118 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stephanie S","family":"Buss","sequence":"additional","affiliation":[{"name":"Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center , 330 Brookline Ave., Boston, MA 02215 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter J","family":"Fried","sequence":"additional","affiliation":[{"name":"Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center , 330 Brookline Ave., Boston, MA 02215 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4531-1967","authenticated-orcid":false,"given":"Mouhsin M","family":"Shafi","sequence":"additional","affiliation":[{"name":"Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center , 330 Brookline Ave., Boston, MA 02215 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katherine W","family":"Turk","sequence":"additional","affiliation":[{"name":"Center for Translational Cognitive Neuroscience, VA Boston Healthcare System , 150 S. Huntington Ave, Boston, MA 02130 ,","place":["United States"]},{"name":"Alzheimer's Disease Research Center, Department of Neurology, Boston University, Chobanian and Avedisian School of Medicine , 72 E Concord St., Boston, MA 02118 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kathy Y","family":"Xie","sequence":"additional","affiliation":[{"name":"Center for Translational Cognitive Neuroscience, VA Boston Healthcare System , 150 S. Huntington Ave, Boston, MA 02130 ,","place":["United States"]},{"name":"Alzheimer's Disease Research Center, Department of Neurology, Boston University, Chobanian and Avedisian School of Medicine , 72 E Concord St., Boston, MA 02118 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0548-9074","authenticated-orcid":false,"given":"Brandon","family":"Frank","sequence":"additional","affiliation":[{"name":"Center for Translational Cognitive Neuroscience, VA Boston Healthcare System , 150 S. Huntington Ave, Boston, MA 02130 ,","place":["United States"]},{"name":"Alzheimer's Disease Research Center, Department of Neurology, Boston University, Chobanian and Avedisian School of Medicine , 72 E Concord St., Boston, MA 02118 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Brice","family":"Passera","sequence":"additional","affiliation":[{"name":"Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center , 330 Brookline Ave., Boston, MA 02215 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2832-1300","authenticated-orcid":false,"given":"Recep Ali","family":"Ozdemir","sequence":"additional","affiliation":[{"name":"Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center , 330 Brookline Ave., Boston, MA 02215 ,","place":["United States"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2913-0015","authenticated-orcid":false,"given":"Andrew E","family":"Budson","sequence":"additional","affiliation":[{"name":"Center for Translational Cognitive Neuroscience, VA Boston Healthcare System , 150 S. 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