Zafer Keser

Dr. Zafer Keser


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

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

Representative Publications

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2 September 2022 in Vascular Health and Risk Management
Verified
Journal Article
Open access
PDF file
ZKZafer Keser
Zafer Keser
CCChia-Chun Chiang
Chia-Chun Chiang
JBJohn C Benson
John C Benson
APAlessandro Pezzini
Alessandro Pezzini
GLGiuseppe Lanzino
Giuseppe Lanzino
Cervical Artery Dissection (CeAD) is a frequent stroke etiology for patients younger than 50 years old. The most common immediate complications related to CeAD are headache and neck pain (65– 95%), TIA/ischemic stroke (> 50%), and partial Horner’s syndrome (25%). The prevailing hypothesis regarding the pathogenesis of sCeAD is that the underlying constitutional vessel wall weakness of patients with sCeAD is genetically determined and that environmental factors could act as triggers. The stroke prevention treatment of CeAD remains controversial, involving anticoagulation or antiplatelet therapy and potentially emergent stenting and/or thrombectomy or angioplasty for selected cases of carotid artery dissection with occlusion. The treatment of headache associated with CeAD depends on the headache phenotype and comorbidities. Radiographically, more than 75% of CeAD cases present with occlusion or non-occlusive stenosis. Many patients demonstrate partial and complete healing, more commonly in the carotid arteries. One-fifth of the patients develop dissecting pseudoaneurysm, but this is a benign clinical entity with an extremely low rupture and stroke recurrence risk. Good recovery is achieved in many CeAD cases, and mortality remains low. Family history of CeAD, connective tissue disorders like Ehlers-Danlos syndrome type IV, and fibromuscular dysplasia are risk factors for recurrent CeAD, which can occur in 3– 9% of the cases. This review serves as a comprehensive, updated overview of CeAD, emphasizing etiopathogenesis and management.

22 February 2022 in Frontiers in Neurology
Verified
Journal Article
Open access
ZKZafer Keser
Zafer Keser
SBSamuel C. Buchl
Samuel C. Buchl
NSNathan A. Seven
Nathan A. Seven
MMMatej Markota
Matej Markota
HCHeather M. Clark
Heather M. Clark
BLBrian N. Lundstrom
Brian N. Lundstrom
Stroke is one of the leading causes of death and disability. Despite the high prevalence of stroke, characterizing the acute neural recovery patterns that follow stroke and predicting long-term recovery remains challenging. Objective methods to quantify and characterize neural injury are still lacking. Since neuroimaging methods have a poor temporal resolution, EEG has been used as a method for characterizing post-stroke recovery mechanisms for various deficits including motor, language, and cognition as well as predicting treatment response to experimental therapies. In addition, transcranial magnetic stimulation (TMS), a form of non-invasive brain stimulation, has been used in conjunction with EEG (TMS-EEG) to evaluate neurophysiology for a variety of indications. TMS-EEG has significant potential for exploring brain connectivity using focal TMS-evoked potentials and oscillations, which may allow for the system-specific delineation of recovery patterns after stroke. In this review, we summarize the use of EEG alone or in combination with TMS in post-stroke motor, language, cognition, and functional/global recovery. Overall, stroke leads to a reduction in higher frequency activity (≥8 Hz) and intra-hemispheric connectivity in the lesioned hemisphere, which creates an activity imbalance between non-lesioned and lesioned hemispheres. Compensatory activity in the non-lesioned hemisphere leads mostly to unfavorable outcomes and further aggravated interhemispheric imbalance. Balanced interhemispheric activity with increased intrahemispheric coherence in the lesioned networks correlates with improved post-stroke recovery. TMS-EEG studies reveal the clinical importance of cortical reactivity and functional connectivity within the sensorimotor cortex for motor recovery after stroke. Although post-stroke motor studies support the prognostic value of TMS-EEG, more studies are needed to determine its utility as a biomarker for recovery across domains including language, cognition, and hemispatial neglect. As a complement to MRI-based technologies, EEG-based technologies are accessible and valuable non-invasive clinical tools in stroke neurology.

1 March 2024 in Stroke
Verified
Journal Article
Closed access
KGKim J. Griffin
Kim J. Griffin
WHWilliam S. Harmsen
William S. Harmsen
JMJay Mandrekar
Jay Mandrekar
RBRobert D. Brown
Robert D. Brown
ZKZafer Keser
Zafer Keser
BACKGROUND: Cervical artery dissection (CeAD) represents up to 15% to 25% of ischemic strokes in people under the age of 50 years. Noninvasive vessel imaging is increasingly used in clinical practice, but the impact on the frequency of detection of CeAD is unknown. In 2006, the yearly incidence rate of CeAD was estimated at 2.6 per 100 000 person-years, but the current incidence is unknown. METHODS: In this population-based retrospective observational cohort study, we utilized the resources of the Rochester Epidemiology Project to ascertain all adult residents of Olmsted County, MN, diagnosed with internal carotid artery dissection and common carotid artery dissection or vertebral artery dissection from 2002 to 2020. Patients with only intracranial involvement or CeAD following major trauma were excluded. Age-adjusted sex-specific and age- and sex-adjusted incidence rates were estimated using the US White 2010 decennial census, with rates expressed per 100 000 person-years. We assessed longitudinal trends by dividing the data into 5-year time intervals, with the last being a 4-year interval. RESULTS: We identified 123 patients with a diagnosis of CeAD. There were 63 patients with internal carotid artery dissection, 54 with vertebral artery dissection, 2 with concurrent internal carotid artery dissection and vertebral artery dissection, and 4 with common carotid artery dissection. There were 63 (51.2%) female patients and 60 (48.8%) male patients. The average age at diagnosis was 50.2 years (SD, 15.1 [95% CI, 20.1–90.5] years). The incidence rate of spontaneous CeAD encompassing all locations was 4.69 per 100 000 person-years (2.43 for internal carotid artery dissection and 2.01 for vertebral artery dissection). The incidence rate increased from 2.30 per 100 000 person-years from 2002 to 2006 to 8.93 per 100 000 person-years from 2017 to 2020 ( P <0.0001). The incidence rate for female patients rose from 0.81 per 100 000 person-years from 2002 to 2006 to 10.17 per 100 000 person-years from 2017 to 2020. CONCLUSIONS: The incidence rate of spontaneous CeAD increased nearly 4-fold over a 19-year period from 2002 to 2020. The incidence rate in women rose over 12-fold. The increase in incidence rates likely reflects the increased use of noninvasive vascular imaging.

1 April 2022 in Mayo Clinic Proceedings
Verified
Journal Article
Closed access
ZKZafer Keser
Zafer Keser
JMJames F. Meschia
James F. Meschia
GLGiuseppe Lanzino
Giuseppe Lanzino

1 March 2020 in Stroke
Verified
Journal Article
Closed access
PDF file
ZKZafer Keser
Zafer Keser
RSRajani Sebastian
Rajani Sebastian
KHKhader M. Hasan
Khader M. Hasan
AHArgye E. Hillis
Argye E. Hillis
Background and Purpose—: Stroke is the leading cause of disability in United States, and aphasia is a common sequela after a left hemisphere stroke. Functional imaging and brain stimulation studies show that right hemisphere structures are detrimental to aphasia recovery but evidence from diffusion tensor imaging is lacking. We investigated the role of homologous language pathways in naming recovery after left hemispheric stroke. Methods—: Patients with aphasia after a left hemispheric stroke underwent naming assessment using the Boston Naming Test and diffusion tensor imaging at the acute and chronic time points. We analyzed diffusion tensor imaging of right arcuate fasciculus and frontal aslant tracts. We used Wilcoxon rank-sum test to evaluate structural lateralization patterns and partial Spearman correlation/multivariate generalized linear model to determine the role of right arcuate fasciculus and frontal aslant tracts in naming recovery after controlling for confounders. Results were corrected for multiple comparisons. Results—: On average, the structural integrity of left language pathways deteriorated more than their right homologs, such that there was rightward lateralization in the chronic stage. Regression/correlation analyses showed that greater preservation of tract integrity of right arcuate fasciculus was associated with poorer naming recovery. Conclusions—: Our study provides preliminary evidence that preservation of right homologs of language pathways is associated with poor recovery of naming after a left hemispheric stroke, consistent with previous evidence that maintaining greater reliance on left hemisphere structures is associated with better language recovery.

1 April 2015 in Progress in Neuro-Psychopharmacology and Biological Psychiatry
Verified
Journal Article
Closed access
JGJuan F. Gálvez
Juan F. Gálvez
ZKZafer Keser
Zafer Keser
BMBenson Mwangi
Benson Mwangi
AGAmna A. Ghouse
Amna A. Ghouse
AFAlbert J. Fenoy
Albert J. Fenoy
JSJair Soares
Jair Soares