Publications by authors named "J S Keene"

451 Publications

Cluster analysis of negative symptoms identifies distinct negative symptom subgroups.

Schizophr Res 2022 Jul 6;246:207-215. Epub 2022 Jul 6.

Department of Psychology, University of Nevada, Las Vegas, United States of America. Electronic address:

The heterogeneity of schizophrenia has been acknowledged for decades because of the diverse presentation of symptoms, illness course, and treatment response noted between individuals diagnosed with the disorder. Cluster analysis has been used as a statistical method to determine whether schizophrenia subgroups might be identified based on symptom heterogeneity. However, there is very limited research examining whether heterogeneity in negative symptoms might be useful in establishing schizophrenia subtypes, particularly research examining newer models of negative symptoms based on five latent constructs including anhedonia, asociality, avolition, blunted affect, and alogia. The Brief Negative Symptom Scale was used to assess the five negative symptoms domains in a sample of 220 outpatients diagnosed with schizophrenia or schizoaffective disorder. Cluster analysis supported a four-cluster solution, comprising clusters of subjects with low negative symptoms (LNS), severe negative symptoms (SNS), and two clusters with moderate negative symptoms, one with predominantly elevated blunted affect (BA) and one with elevated avolition (AV). The LNS, SNS, BA, and AV clusters significantly differed on external validators including clinical characteristics, neurocognition, and functional outcome. Findings suggest that schizophrenia heterogeneity can be parsed according to negative symptom subtypes that have distinct clinical and neuropsychological profiles. Implications for diagnosis and treatment are discussed.
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http://dx.doi.org/10.1016/j.schres.2022.06.021DOI Listing
July 2022

Retrospective Evaluation of First-line Levetiracetam use for Neonatal Seizures after Congenital Heart Defect repair with or without Extracorporeal Membrane Oxygenation.

J Pediatr Pharmacol Ther 2022 21;27(3):254-262. Epub 2022 Mar 21.

University of Washington, Department of Neurology, Division of Child Neurology (JK, MW, LM, XB, NN), Seattle, WA.

Objective: Levetiracetam (LEV) efficacy for neonatal seizures is debated. We evaluated LEV as a first line anti-seizure medicine (ASM) in neonates following neonatal congenital heart defect (CHD) repair who did not require extracorporeal membrane oxygenation (ECMO) vs neonates who required ECMO.

Methods: A single center retrospective review of neonates with CHD from 2015 to 2020 was conducted. Neonates were included if seizures were present on continuous EEG after CHD repair either on or off ECMO, and they received LEV as a first line ASM. Primary outcomes were seizure resolution with LEV, adverse events and response to subsequent ASM.

Results: Eighteen total neonates were evaluated, 10 with seizures post-CHD repair who did not require ECMO and 8 who required ECMO. In the non-ECMO cohort, nine of ten were successfully treated with LEV monotherapy with no adverse events. In comparison, the eight neonates who required ECMO had a higher initial seizure burden (1.6% vs 17%, p=0.003), were more likely to have injury on neuroimaging (12.5 vs 75%, p= 0.04), and all neonates required multiple ASMs. Seizure burden did not decrease with LEV, but significantly decreased with phenobarbital and fosphenytoin (14.4% and 10.5%, p = 0.024).

Conclusions: Neonates with CHD and seizures on and off ECMO demonstrated divergent seizure characteristics including seizure burden and response to LEV. LEV may reduce neonatal seizure burden after uncomplicated CHD repair. However, in neonates requiring ECMO, multiple ASMs were required. A prospective evaluation of ASM efficacy and safety in this high-risk population is urgently needed.
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http://dx.doi.org/10.5863/1551-6776-27.3.254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8939278PMC
March 2022

Ultrafast spectroscopy studies of carrier dynamics in semiconductor nanocrystals.

iScience 2022 Feb 1;25(2):103831. Epub 2022 Feb 1.

Department of Chemistry, Vanderbilt University, Nashville, TN 37240, USA.

Semiconductor nanocrystals have become ubiquitous both in scientific research and in applied technologies related to light. When a nanocrystal absorbs a photon an electron-hole pair is created whose fate dictates whether the nanocrystal will be suitable for a particular application. Ultrafast spectroscopy provides a real-time window to monitor the evolution of the electron-hole pair. In this review, we focus on CdSe nanocrystals, the most-studied nanocrystal system to date, and also highlight ultrasmall nanocrystals, "standard nanocrystals" of different binary composition, alloyed nanocrystals, and core/shell nanocrystals and nanorods. We focus on four time-resolved spectroscopies used to interrogate nanocrystals: pump-probe, fluorescence upconversion, time-correlated single photon counting, and non-linear spectroscopies. The basics of the nanocrystals and the spectroscopies are presented, followed by a detailed synopsis of ultrafast spectroscopy studies performed on the various semiconductor nanocrystal systems.
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http://dx.doi.org/10.1016/j.isci.2022.103831DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8844678PMC
February 2022

Cognitive profiles following sport-related concussion in high school athletes.

Neuropsychology 2022 Feb 9;36(2):159-174. Epub 2021 Dec 9.

Department of Psychology.

Objective: Heterogeneity is common following traumatic brain injury (TBI) with important implications for clinical outcome. Research in moderate to severe TBI identifies differentiated cognitive profiles. There is little research investigating potential clusters following sport concussion.

Methods: Cluster analysis was used to determine patterns of Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) performance at three time points (72 hr, 4-7 days, and 8-30 days postconcussion). Participants included 1,817 high-school athletes ( = 15.5; 37.9% female) who completed ImPACT following concussion.

Results: Separate cluster analyses of cognitive scores were conducted at each postconcussion timepoint. Results indicated three clusters of cognitive performance within 1 week postinjury, while a two-cluster solution was identified at longer intervals (8-30 days). Clusters differed primarily by level of performance and also exhibited stratified differences in symptom severity and magnitude of change in cognitive function and symptom-reporting from pre- to postconcussion. The lowest performing cluster in each PC group was Mildly-to-Moderately Impaired and exhibited the highest rates of complicated recovery, suggesting an association between the current clusters and protracted recovery.

Conclusions: Results provide preliminary evidence that ImPACT can identify clusters of athletes based on cognitive performance postconcussion that differ in clinically meaningful ways, including symptoms, magnitude of change from baseline, and concussion recovery outcomes. Discriminant functions can classify athletes into clusters based on postconcussion scores and a supplemental excel calculator is provided for such purposes. Absence of full demographic data regarding race/ethnicity and socioeconomic status may limit generalizability. Future work should investigate whether these clusters may assist in return-to-play decision-making by identifying at-risk athletes who may benefit from targeted intervention. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
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http://dx.doi.org/10.1037/neu0000787DOI Listing
February 2022

Treatment of Neonatal Seizures: Comparison of Treatment Pathways From 11 Neonatal Intensive Care Units.

Pediatr Neurol 2022 03 11;128:67-74. Epub 2021 Oct 11.

Division of Pediatric Neurology, Departments of Neurology and Pediatrics, University of Washington, Seattle Children's Hospital, Seattle, Washington.

Objective: Seizures are a common neonatal neurologic emergency. Many centers have developed pathways to optimize management. We evaluated neonatal seizure management pathways at level IV neonatal intensive care units (NICUs) in the United States to highlight areas of consensus and describe aspects of variability.

Methods: We conducted a descriptive analysis of 11 neonatal seizure management pathways from level IV NICUs that specialize in neonatal neurocritical care including guidelines for electroencephalography (EEG) monitoring, antiseizure medication (ASM) choice, timing, and dose.

Results: Study center NICUs had a median of 70 beds (interquartile range: 52-96). All sites had 24/7 conventional EEG initiation, monitoring, and review capability. Management pathways uniformly included prompt EEG confirmation of seizures. Most pathways included a provision for intravenous benzodiazepine administration if either EEG or loading of ASM was delayed. Phenobarbital 20 mg/kg IV was the first-line ASM in all pathways. Pathways included either fosphenytoin or levetiracetam as the second-line ASM with variable dosing. Third-line ASMs were most commonly fosphenytoin or levetiracetam, with alternatives including topiramate or lacosamide. All pathways provided escalation to continuous midazolam infusion with variable dosing for seizures refractory to initial medication trials. Three pathways also included lidocaine infusion. Nine pathways discussed ASM discontinuation after resolution of acute symptomatic seizures with variable timing.

Conclusions: Despite a paucity of data from controlled trials regarding optimal neonatal seizure management, there are areas of broad agreement among institutional pathways. Areas of substantial heterogeneity that require further research include optimal second-line ASM, dosage, and timing of ASM discontinuation.
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http://dx.doi.org/10.1016/j.pediatrneurol.2021.10.004DOI Listing
March 2022
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