ORIGINAL ARTICLE Executive Function Deficits in Acute Stroke Sandra Zinn, PhD, Hayden B. Bosworth, PhD, Helen M. Hoenig, MD, H. Scott Swartzwelder, PhD ABSTRACT. Zinn S, Bosworth HB, Hoenig HM, Swartzwelder HS. Executive function deficits in acute stroke. Arch Phys Med Rehabil 2007;88:173-80. Objectives: To establish the frequency of executive dys- function during acute hospitalization for stroke and to examine the relationship of that dysfunction to stroke severity and premorbid characteristics. Design: Inception cohort study. Setting: Inpatient wards at a Veterans Affairs hospital. Participants: Consecutive sample of inpatients with radio- logically or neurologically confirmed stroke. Final sample in- cluded 47 patients screened for aphasia and capable of neuro- psychologic testing. Two nonstroke inpatient control samples (n=10 each) with either transient ischemic attack (TIA) or multiple stroke risk factors were administered the same re- search procedure and tests. Interventions: Not applicable. Main Outcome Measures: Composite cognitive impair- ment ratio (CIR), calculated from 8 scores indicative of exec- utive function on 6 neuropsychologic tests by dividing number of tests completed into the number of scores falling below cutoff point, defined as 1.5 standard deviations below norma- tive population mean. Results: Stroke patients had a mean CIR of .61, compared with .48 for TIAs and .44 for stroke-risk-only. Analysis of variance revealed that CIRs of stroke-risk-only patients but not TIAs were lower than those of the stroke patients (P=.02). Impairment frequencies were at least 50% for stroke patients on most test scores. The Symbol Digit Modalities Test (75% impairment) and a design fluency measure distinguished stroke from nonstroke patients. CIR was not related to stroke severity in the stroke patient sample, but was related to estimated premorbid intelligence. Conclusions: Executive function deficits are common in stroke patients. The data suggest that limitations in information processing due to these deficits may require environmental and procedural accommodations to increase rehabilitation benefit. Key Words: Attention; Cognition disorders; Rehabilitation; Stroke. © 2007 by the American Congress of Rehabilitation Medi- cine and the American Academy of Physical Medicine and Rehabilitation P ATIENTS WITH RECENT STROKE who are beginning rehabilitation often have cognitive impairment, either pre- dating or acquired with the stroke. Deficits in the particular cognitive processes known as executive functions, which man- age goal-oriented behavior, are common poststroke 1,2 and re- duce stroke treatment effectiveness. 3,4 Current knowledge of executive function deficits is typically based on studies con- ducted 3 months or more poststroke. Prevalence of executive function deficits may be even higher early after stroke, when the initial rehabilitative training occurs, but this is unknown. No neuropsychologic studies of executive functions in acute stroke have been conducted, to our knowledge. Although executive functions may broadly be said to man- age goal-oriented behavior, several component processes have been identified. Important components of the executive func- tions include starting and stopping behavior at appropriate times, persisting at a task or switching tactics as needed, and selecting behaviors in novel situations based on context and higher-level or long-term goals. These components are also denoted (respectively) as initiation/perseveration, cognitive persistence and flexibility, self-monitoring, and abstract think- ing (including planning). Working memory, the capacity for storing and manipulating data during problem solving, is de- pendent on frontal cortex (and other brain regions) and is often included as an executive function. Combined deficits of these components create impairments that can compromise rehabilitation treatment in varying ways. For example, rehabilitation patients with deficits in initiation and persistence may have a reduced capacity to initiate, se- quence, and sustain a series of exercises, due to their executive function impairment, and thus have reduced functional recov- ery after stroke. 3 Deficits of initiation and perseveration may also result in an impairment, producing compulsive repetition of a behavioral sequence. 5 Impairments of planning and/or problem-solving can lead to unsafe physical maneuvers and increase the risk of falls. 6,7 When there is a generalized deficit of attention and/or cognitive speed in addition to executive function deficits, the ability to process novel or complex infor- mation is curtailed, leading to limits in information processing capacity. 8 Impaired planning, reduced prospective memory (remembering to remember something), and reduced informa- tion-processing capacity may make it difficult for rehabilitation patients to remember and follow the complex treatment regi- mens, often provided at discharge, that are designed to promote functional gains and reduce their risk of stroke recurrence. Post-rehabilitation functional improvement has been related to executive function scores 9 and providing cognitive remediation has improved performance of activities of daily living (ADLs) in stroke patients. 10 Poststroke cognitive impairment of any type has been re- peatedly related to stroke severity, 11,12 but recent studies sug- gest that executive function decline may begin prior to com- pleted strokes. 13-17 It appears that small vessel ischemic disease in white and subcortical gray matter leads to decrements in executive functioning 18-20 that primarily affect processing speed 21 and cognitive flexibility. 15 Functional decline, espe- cially in instrumental ADLs, has been related to executive function impairment even in community-dwelling sam- ples. 22-25 Thus any executive function deficit occurring as a From Research and Development (Zinn, Swartzwelder), Health Services and De- velopment (Bosworth), and Department of Physical Medicine and Rehabilitation (Hoenig), Veterans Affairs Medical Center, Durham, NC; and Departments of Psy- chiatry (Zinn, Bosworth, Swartzwelder) and Medicine (Swartzwelder), Duke Univer- sity Medical Center, Durham, Durham, NC. Supported by Veterans Affairs Rehabilitation Research & Development (career development award). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated. Reprint requests to Sandra Zinn, PhD, Research & Development (151), VA Medical Center, 508 Fulton St, Durham, NC 27705, e-mail: sandra.zinn@duke.edu. 0003-9993/07/8802-10656$32.00/0 doi:10.1016/j.apmr.2006.11.015 173 Arch Phys Med Rehabil Vol 88, February 2007