Eric John Heyer

Dr. Eric John Heyer


Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 February 2002 in Archives of Neurology
Verified
Journal Article
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EHEric John Heyer
Eric John Heyer
RSRuchey Sharma
Ruchey Sharma
ARAnita Rampersad
Anita Rampersad
CWChristopher J. Winfree
Christopher J. Winfree
WMWilliam J. Mack
William J. Mack
ECE. Sander Connolly
E. Sander Connolly
CAROTID endarterectomy (CEA) is an effective means of preventing stroke in appropriately selected patients.1-4 Although the incidence of perioperative stroke is low, subtle cognitive changes as revealed by neuropsychological (NP) testing occur in a high percentage of patients following CEA. Several studies have demonstrated improvement,5-10 others show no change,11,12 and still others demonstrate a decline13-15 in postoperative NP performance. Although decline in NP performance may be related to intraoperative hemispheric cerebral ischemia,16,17 microemboli,18 or subclinical microinfarcts,13 some decline may be due to the effects of general anesthesia,19,20 particularly in older patients.21 Most previous studies have not controlled for the effects of perioperative variables, such as anesthesia, stress, and pain.

1 June 1998 in Stroke
Verified
Journal Article
Closed access
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EHEric John Heyer
Eric John Heyer
DADavid C. Adams
David C. Adams
RSRobert A. Solomon
Robert A. Solomon
GTGeorge J. Todd
George J. Todd
DQDonald O. Quest
Donald O. Quest
ECE. Sander Connolly
E. Sander Connolly
Background and Purpose —One hundred twelve patients undergoing elective carotid endarterectomy for symptomatic and asymptomatic carotid artery stenosis were enrolled in a prospective study to evaluate the incidence of change in postoperative cerebral function. Methods —Patients were evaluated preoperatively and postoperatively before hospital discharge and at follow-up 1 and 5 months later with a battery of neuropsychometric tests. The results were analyzed by both event-rate and group-rate analyses. For event-rate analysis, change was defined as either a decline or improvement in postoperative neuropsychometric performance by 25% or more compared with a preoperative baseline. Results —Approximately 80% of patients showed decline in one or more test scores, and 60% had one or more improved test scores at the first follow-up examination. The percentage of declined test scores decreased and the percentage of improved test scores increased with subsequent follow-up examinations. Group-rate analysis was similar for group performance on individual tests. However, a decline in performance was seen most commonly on verbal memory tests, and improved performance was seen most commonly on executive and motor tests. Conclusions —Neuropsychometric evaluation of patients undergoing carotid endarterectomy for significant carotid artery stenosis demonstrates both declines and improvements in neuropsychometric performance. The test changes that showed decreased performance may be associated with ischemia from global hypoperfusion or embolic phenomena, and the improvement seen may be related to increased cerebral blood flow from removal of stenosis.

1 March 2006 in Neurosurgery
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Journal Article
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EHEric John Heyer
Eric John Heyer
RDRobert DeLaPaz
Robert DeLaPaz
HHHadi J. Halazun
Hadi J. Halazun
ARAnita Rampersad
Anita Rampersad
RSRobert Sciacca
Robert Sciacca
ECE Sander Connolly
E Sander Connolly
OBJECTIVE: Neurocognitive dysfunction has been shown to occur in roughly 25% of patients undergoing carotid endarterectomy (CEA). Despite this, little is known about the mechanism of this injury. Recently, several groups have shown that new diffusion weighted imaging (DWI)-positive lesions are seen in 20% of patients undergoing CEA. We investigated to what degree neurocognitive dysfunction was associated with new DWI lesions. METHODS: Thirty-four consecutive patients undergoing CEA were subjected to pre- and postoperative cognitive evaluation with a battery of neuropsychological tests. Postoperative magnetic resonance imaging was performed in all patients within 24 hours of surgery. Lesions that showed high signal on DWI and restricted diffusion on apparent diffusion coefficient maps but no abnormal high signal on the fluid-attenuated inversion recovery images were considered hyperacute. RESULTS: Cognitive dysfunction was seen in eight (24%) patients. New hyperacute DWI lesions were seen in three (9%). Only one (13%) of the patients with cognitive dysfunction had a new DWI lesion. Two thirds of the new DWI lesions occurred in the absence of cognitive deterioration. Patients with cognitive dysfunction had significantly longer carotid cross-clamp times. CONCLUSION: Neurocognitive dysfunction after CEA does not seem to be associated with new DWI positive lesions.

1 January 2006 in Mayo Clinic Proceedings
Verified
Journal Article
Closed access
CCChristopher J. Chisholm
Christopher J. Chisholm
JZJoseph Zurica
Joseph Zurica
DMDmitry Mironov
Dmitry Mironov
RSRobert R. Sciacca
Robert R. Sciacca
EOEugene Ornstein
Eugene Ornstein
EHEric John Heyer
Eric John Heyer

1 February 2009 in Anesthesiology
Verified
Journal Article
Open access
PDF file
GYGene T. Yocum
Gene T. Yocum
JGJohn G. Gaudet
John G. Gaudet
LTLauren A. Teverbaugh
Lauren A. Teverbaugh
DQDonald O. Quest
Donald O. Quest
PMPaul C. McCormick
Paul C. McCormick
EHEric John Heyer
Eric John Heyer
Background: Cognitive dysfunction is fairly common after noncardiac surgery and may be related to intraoperative blood pressure management. The authors present an analysis of risk factors for cognitive deterioration after spine surgery in older patients, with particular emphasis on intraoperative blood pressure in normotensive and hypertensive patients. Methods: This is a post hoc cohort analysis of 45 patients enrolled before undergoing lumbar laminectomy or microdiscectomy. The patients underwent a battery of 5 neuropsychometric tests preoperatively, and 1 day and 1 month postoperatively. Computerized anesthesia records were used to obtain intraoperative mean arterial pressure (MAP) data. Simple linear regressions between intraoperative MAP and postoperative cognitive performance were performed, and multivariate linear regression models of postoperative cognitive performance were constructed to analyze potential risk factors for cognitive decline after surgery. Results: Twenty-one normotensive patients (mean age, 62.4 yr) and 24 hypertensive patients (mean age, 67.9 yr) were included in this analysis. There was a significant positive relationship between minimum intraoperative MAP values and 1-day cognitive performance by simple linear regression in hypertensive (P = 0.003), but not normotensive, patients. In multivariate linear regression analysis of cognitive performance, there was a significant interaction between hypertension and minimum intraoperative MAP at 1 day and 1 month. Conclusions: In hypertensive patients, there was a significant relationship between minimum intraoperative MAP and decline in cognitive function 1 day and 1 month after surgery. A prospective controlled trial of intraoperative blood pressure control, especially during induction of anesthesia when MAP values typically drop, is needed to confirm these findings.

1 October 2000 in Journal of Clinical and Experimental Neuropsychology
Verified
Journal Article
Closed access
EHEric John Heyer
Eric John Heyer
RSR Sharma
R Sharma
CWC J Winfree
C J Winfree
JMJ Mocco
J Mocco
DMD J McMahon
D J McMahon
ECE S Connolly
E S Connolly
There is little information on the effect of pain on neuropsychological test performance. We have undertaken this study to explore which tests are affected by pain, the magnitude of these changes, ...