Daniel Storzbach

U.S. Department of Veterans Affairs, Washington, D. C., DC, USA

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Publications (13)40.92 Total impact

  • Article: Psychiatric comorbidity in veterans with psychogenic seizures.
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    ABSTRACT: Psychogenic non-epileptic seizures (PNES) are frequently encountered in epilepsy monitoring units (EMU) at Veterans Affairs Medical Centers (VAMCs) and cause significant long-term disability. An understanding of psychiatric factors associated with PNES could aid in earlier diagnosis and treatment. We studied 50 consecutive veterans diagnosed with PNES and 37 veterans diagnosed with epileptic seizures (ES), evaluated at a VAMC EMU. We reviewed all available mental health evaluations prior to EMU evaluation. Univariate comparisons included axis I diagnoses, axis II diagnoses, and psychiatric hospitalizations. Predictive models of seizure classification were evaluated by logistic regression. A diagnosis of post-traumatic stress disorder (PTSD) preceded the diagnosis of PNES in 58% of patients and the diagnosis of ES in 13.5% (p<0.001). On logistic regression, PTSD was the only significant psychiatric diagnosis (odds ratio 9.2). Major depression and alcohol abuse were common diagnoses but did not differentiate PNES and ES groups.
    Epilepsy & Behavior 10/2012; 25(3):345-349. · 2.34 Impact Factor
  • Article: Cognitive effects of pregabalin in healthy volunteers: a double-blind, placebo-controlled trial.
    Martin Salinsky, Daniel Storzbach, Sonia Munoz
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    ABSTRACT: Antiepileptic drugs (AEDs) can be associated with neurotoxic side effects including cognitive dysfunction, a problem of considerable importance given the usual long-term course of treatment. Pregabalin is a relatively new AED widely used for the treatment of seizures and some types of chronic pain including fibromyalgia. We measured the cognitive effects of 12 weeks of pregabalin in healthy volunteers. Thirty-two healthy volunteers were randomized in a double-blind parallel study to receive pregabalin or placebo (1:1). Pregabalin was titrated over 8 weeks to 600 mg/d. At baseline, and after 12 weeks of treatment, all subjects underwent cognitive testing. Test-retest changes in all cognitive and subjective measures were Z scored against test-retest regressions previously developed from 90 healthy volunteers. Z scores from the placebo and pregabalin groups were compared using Wilcoxon tests. Thirty subjects completed the study (94%). Three of 6 target cognitive measures (Digit Symbol, Stroop, Controlled Oral Word Association) revealed significant test-retest differences between the pregabalin and placebo groups, all showing negative effects with pregabalin (p < 0.05). These cognitive effects were paralleled by complaints on the Portland Neurotoxicity Scale, a subjective measure of neurotoxicity (p < 0.01). At conventional doses and titration, pregabalin induced mild negative cognitive effects and neurotoxicity complaints in healthy volunteers. These effects are one factor to be considered in the selection and monitoring of chronic AED therapy. Class of Evidence: This study provides Class I evidence that pregabalin 300 mg BID negatively impacts cognition on some tasks in healthy volunteers.
    Neurology 03/2010; 74(9):755-61. · 8.31 Impact Factor
  • Article: A pilot study examining effects of group-based Cognitive Strategy Training treatment on self-reported cognitive problems, psychiatric symptoms, functioning, and compensatory strategy use in OIF/OEF combat veterans with persistent mild cognitive disorder and history of traumatic brain injury.
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    ABSTRACT: We aimed to determine whether group-based Cognitive Strategy Training (CST) for combat veterans with mild cognitive disorder and a history of traumatic brain injury (TBI) has significant posttreatment effects on self-reported compensatory strategy usage, functioning, and psychiatric symptoms. Participants included 21 veterans returning from conflicts in Iraq or Afghanistan with a diagnosis of Cognitive Disorder, Not Otherwise Specified and a history of combat-related TBI. Participants attended 6- to 8-week structured CST groups designed to provide them training in and practice with a variety of compensatory cognitive strategies, including day planner usage. Of the participants, 16 completed pre- and posttreatment assessment measures. Following CST, participants reported significantly increased use of compensatory cognitive strategies and day planners; an increased perception that these strategies were useful to them; increased life satisfaction; and decreased depressive, memory, and cognitive symptom severity. Group-based CST is a promising intervention for veterans with mild cognitive disorder, and randomized controlled trials are required to further evaluate its efficacy.
    The Journal of Rehabilitation Research and Development 01/2010; 47(1):43-60. · 1.78 Impact Factor
  • Article: MMPI-2 profiles: fibromyalgia patients compared to epileptic and non-epileptic seizure patients.
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    ABSTRACT: We compared MMPI-2 profiles of Gulf War veterans with fibromyalgia (FM) to epileptic seizure (ES) patients, psychogenic non-epileptic seizure (PNES) patients, and Gulf War veteran healthy controls. Both PNES and FM are medically unexplained conditions. In previous MMPI-2 research PNES patients were shown to have significantly higher Hs and Hy clinical scales than ES patients. In the present research the FM group had significantly higher Hs and Hy scale scores than both the ES group and the healthy control group. There was no significant difference between the FM and PNES Hs scale scores; however, the FM Hy scale score was significantly lower than the PNES Hy scale score. Present findings indicate a high level of psychological distress in the FM group.
    The Clinical Neuropsychologist 10/2009; 24(2):220-34. · 2.12 Impact Factor
  • Article: The cognitive effects of hepatitis C in the presence and absence of a history of substance use disorder.
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    ABSTRACT: The aim of the study was to determine whether infection with the hepatitis C virus (HCV) is associated with cognitive impairment beyond the effects of prevalent comorbidities and a history of substance use disorder (SUD). Adult veterans were recruited from the Portland Veterans Affairs Medical Center into three groups: (1) HCV+/SUD+ (n = 39), (2) HCV+/SUD- (n = 24), and (3) HCV-/SUD- (n = 56). SUD+ participants were in remission for > or =90 days, while SUD- participants had no history of SUD. Groups did not significantly differ in terms of rates of psychiatric or medical comorbidities. Procedures included clinical interviews, medical record reviews, and neuropsychological testing. Significant group differences were found in the domains of Verbal Memory, Auditory Attention, Speeded Visual Information Processing, and Reasoning/Mental Flexibility (p <or = .05). Post hoc comparisons indicated that HCV+/SUD- patients performed significantly worse than HCV-/SUD- controls on tests measuring verbal learning, auditory attention, and reasoning/mental flexibility, but only HCV+/SUD+ patients did worse than HCV-/SUD- controls on tests of speeded visual information processing. Results indicate that chronic HCV is associated with cognitive impairment in the absence of a history of SUD. The most robust deficits appear to be in verbal learning and reasoning/mental flexibility. (JINS, 2009, 15, 69-82.).
    Journal of the International Neuropsychological Society 01/2009; 15(1):69-82. · 2.76 Impact Factor
  • Article: Topiramate effects on the EEG and alertness in healthy volunteers: a different profile of antiepileptic drug neurotoxicity.
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    ABSTRACT: Previous quantitative EEG (QEEG) studies of carbamazepine (CBZ), oxcarbazepine (OXC), and phenytoin (PHT) revealed a pattern of EEG slowing and an increase in drowsiness on the awake maintenance task (AMT). EEG slowing has been shown to correlate with negative effects on cognitive tests. Topiramate (TPM) is a novel AED with relatively large negative effects on cognitive function. We tested the hypothesis that TPM would induce significant slowing of EEG background rhythms and an increase in AMT drowsiness. Forty healthy volunteers were randomized to TPM, gabapentin (GBP), or placebo. Doses were escalated as tolerated to a maximum of 400mg/day for TPM or 3600 mg/day for GBP, over a 10-week period, followed by a minimum 2-week plateau period. Volunteers underwent an EEG, cognitive tests, and the AMT prior to starting an AED and again 12 weeks later. The EEG was captured using a structured recording protocol and quantified using the fast Fourier transform. Four target measures were derived from the averaged occipital electrodes (peak frequency of the dominant posterior rhythm, median frequency, percentage theta, and percentage delta). Test-retest changes for all measures were scored against similar test-retest distributions previously obtained from untreated healthy volunteers. TPM produced no significant change in any of the four target EEG measures or on the AMT, even though several target cognitive tests revealed moderate or greater negative effects. There were also no significant changes in the placebo group. GBP slowed the peak and median frequency EEG measures and increased the percentage of theta and delta activity. Neither TPM, GBP, nor placebo caused a significant increase in drowsiness on the AMT. TPM has a unique neurotoxicity profile. It has no effect on EEG background measures or on the AMT, but induces moderate to large negative changes in many cognitive test scores. This profile differs from those of CBZ, OXC, PHT, and GBP.
    Epilepsy & Behavior 06/2007; 10(3):463-9. · 2.34 Impact Factor
  • Article: MMPI-2 profiles of persons with multiple chemical sensitivity.
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    ABSTRACT: We compared the MMPI-2 profiles of adults with multiple chemical sensitivity (MCS), epileptic seizures (ES), and nonepileptic seizures (NES). Both NES and MCS are medically unexplained conditions. In previous studies profiles associated with NES were elevated on scales Hs and Hy, compared with profiles associated with ES. We predicted that profiles associated with MCS would be elevated on Hs and Hy compared with the ES group. Patients with ES and NES were diagnosed after intensive EEG monitoring using published criteria. MCS was diagnosed if there was a complaint of illness in response to multiple common odors at levels that are not noxious to most people. All the MCS cases had legal claims for injury related to chemical exposures. The results showed that on MMPI-2 scales Hs, D, and Hy the MCS group had means significantly higher than both the ES and NES groups. Fake Bad Scale scores were elevated in 11 MCS cases, and regression-based estimates of Fake Bad Scale scores showed elevation in the MCS group compared with both seizure groups. We conclude that MMPI-2 data, obtained from people seeking financial compensation, indicate that there is a strong psychological component to MCS symptoms.
    The Clinical Neuropsychologist 01/2007; 20(4):848-57. · 2.12 Impact Factor
  • Article: The Portland Neurotoxicity Scale: validation of a brief self-report measure of antiepileptic-drug-related neurotoxicity.
    Martin C Salinsky, Daniel Storzbach
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    ABSTRACT: The Portland Neurotoxicity Scale (PNS) is a brief patient-based survey of neurotoxicity complaints commonly encountered with the use of antiepileptic drugs (AEDs). The authors present data on the validity of this scale, particularly when used in longitudinal studies. Participants included 55 healthy controls, 23 epilepsy patient controls, and 86 healthy volunteers who took various AEDs or placebos for 12 weeks as part of randomized, double-blind studies of AED effects on cognitive abilities. Test-retest reliability in the control groups averaged .80 (total score). Test-retest changes in the PNS were sensitive to AED usage in general (p < .001) and to each of the five AEDs tested but not to placebo. Test-retest changes in the PNS were strongly correlated with several scales of the Profile of Mood States but only weakly correlated with objective cognitive test measures. The PNS has satisfactory psychometric properties and is sensitive to AED usage in test-retest studies.
    Assessment 03/2005; 12(1):107-17. · 2.01 Impact Factor
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    Article: Measures of short-term test-retest reliability of computerized neurobehavioral tests.
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    ABSTRACT: Neurobehavioral test batteries are often administered repeatedly to evaluate changes over time or effects of clinical interventions or neurotoxic exposures. Time intervals between test sessions range from very short (hours) to very long (decades). The aim of this study was to compare the impact of two brief time intervals on the test-retest reliability of frequently used neurobehavioral tests. Fifty healthy adults were recruited through newspaper advertisements in Portland, Oregon. Participants were divided into either a 6h (same-day) or 1-week retest group. All participants completed a battery of tests from the computerized Behavioral Assessment and Research System (BARS). Reliability was assessed by Pearson product-moment correlation and by intraclass correlation coefficient (ICC). The test battery generally showed adequate reliability in the short-term (week) and very short-term (day) and stability in performance over repeated administration when examined by multiple measures. Intraclass correlation coefficient ranged from 0.35 to 0.85. The magnitude of variation of performance in the administered tests was equally distributed around zero (i.e. no difference). The findings suggest that neurobehavioral tests such as BARS may be a useful tool for the assessment of acute exposures and clinical status where short-term evaluation is required (e.g. in the same-day or within 1 week).
    NeuroToxicology 09/2003; 24(4-5):513-21. · 3.10 Impact Factor
  • Article: Assessment of CNS effects of antiepileptic drugs by using quantitative EEG measures.
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    ABSTRACT: Antiepileptic drugs (AEDs) can be associated with adverse neurologic effects including cognitive dysfunction. Objective methods for recognizing AED effects on the brain could be valuable for long-term management. We compared quantitative EEG measures and cognitive tests in a group of patients beginning or ending AED therapy. Subjects included 20 patients beginning AED therapy (AEDon), 12 patients stopping AED therapy (AEDoff), 33 patient controls receiving stable AED therapy (AEDco), and 73 healthy controls (Nco). All subjects underwent structured EEG recording and a cognitive test battery before change in AED dose and again 12-16 weeks later, >or=4 weeks after the last dose change. Four occipital EEG measures (peak frequency, median frequency, relative theta and delta power) were analyzed. Cognitive test changes were scored by using test-retest regression equations based on the Nco subjects. Wilcoxon tests were used for two-group comparisons. AEDons had a significant decrease, and AEDoffs, a significant increase in the peak frequency of the EEG rhythm, as compared with controls. Results for median frequency and theta power were similar. Change in the EEG peak frequency correlated with an aggregate cognitive change measure (r2= 0.71; p < 0.001), individual cognitive measures, and subjective complaints. Of the combined AEDon/AEDoff patients, 58% exceeded the 95% confidence interval for test-retest change in EEG peak frequency. Quantitative measures derived from the occipital EEG are sensitive to AEDs and correlate with AED-related cognitive effects and subjective complaints. Although this correlation does not indicate a direct relation, quantified EEG may be a practical measure of AED impact on the brain.
    Epilepsia 08/2003; 44(8):1042-50. · 3.96 Impact Factor
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    Article: Effects of gabapentin and carbamazepine on the EEG and cognition in healthy volunteers.
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    ABSTRACT: Antiepileptic drug (AED) therapy can be associated with neurotoxic side effects including cognitive dysfunction. Objective methods for detection of neurotoxicity in individual patients would be useful. We studied the effects of gabapentin (GBP) and carbamazepine (CBZ) on neurophysiologic and cognitive/behavioral measures in healthy volunteers. In a 12-week, randomized, double-blind, parallel-group study of CBZ and GBP in healthy volunteers, 23 subjects completed the protocol. All achieved the target dose of 1,200 mg CBZ or 3,600 mg GBP. A structured EEG for quantitative analysis and a cognitive test battery were administered before AED therapy and again after 12 weeks of therapy. Test-retest differences were compared with those of 72 untreated control subjects. Both CBZ and GBP significantly decreased the peak frequency of the posterior (alpha) rhythm, with CBZ exerting a greater effect. Ten CBZ and six GBP subjects exceeded the 95% confidence interval (CI) for an individual. Cognitive tests revealed AED vs. control group effects for two of seven measures (Digit Symbol, Stroop) and all subjective measures. However, few subjects exceeded the 95% CI for any objective test. Differences between CBZ and GBP were not significant. Greater EEG slowing was associated with greater subjective neurotoxicity and poorer test-retest performance on a cognitive test summary measure. Prolonged CBZ and GBP therapy induced EEG slowing that correlated with cognitive complaints and often exceeded the confidence interval for individual subjects. Quantitative EEG measures may be useful in the objective determination of AED-related neurotoxicity.
    Epilepsia 06/2002; 43(5):482-90. · 3.96 Impact Factor
  • Article: Effects of Gabapentin and Carbamazepine on the EEG and Cognition in Healthy Volunteers
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    ABSTRACT:  Purpose: Antiepileptic drug (AED) therapy can be associated with neurotoxic side effects including cognitive dysfunction. Objective methods for detection of neurotoxicity in individual patients would be useful. We studied the effects of gabapentin (GBP) and carbamazepine (CBZ) on neurophysiologic and cognitive/behavioral measures in healthy volunteers.Methods: In a 12-week, randomized, double-blind, parallel-group study of CBZ and GBP in healthy volunteers, 23 subjects completed the protocol. All achieved the target dose of 1,200 mg CBZ or 3,600 mg GBP. A structured EEG for quantitative analysis and a cognitive test battery were administered before AED therapy and again after 12 weeks of therapy. Test–retest differences were compared with those of 72 untreated control subjects.Results: Both CBZ and GBP significantly decreased the peak frequency of the posterior (alpha) rhythm, with CBZ exerting a greater effect. Ten CBZ and six GBP subjects exceeded the 95% confidence interval (CI) for an individual. Cognitive tests revealed AED vs. control group effects for two of seven measures (Digit Symbol, Stroop) and all subjective measures. However, few subjects exceeded the 95% CI for any objective test. Differences between CBZ and GBP were not significant. Greater EEG slowing was associated with greater subjective neurotoxicity and poorer test–retest performance on a cognitive test summary measure.Conclusions: Prolonged CBZ and GBP therapy induced EEG slowing that correlated with cognitive complaints and often exceeded the confidence interval for individual subjects. Quantitative EEG measures may be useful in the objective determination of AED-related neurotoxicity.
    Epilepsia 05/2002; 43(5):482 - 490. · 3.96 Impact Factor
  • Article: Subjective Cognitive Complaints, Affective Distress, and Objective Cognitive Performance in Persian Gulf War Veterans
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    ABSTRACT: We examined subjective cognitive complaints, affective distress, and cognitive performance in Persian Gulf veterans who reported illness and cognitive complaints. We predicted a stronger relationship between subjective cognitive complaints and affective distress than between subjective cognitive complaints and objective cognitive performance. This prediction was confirmed in a sample of 100 veterans. The results suggest that cognitive impairment should not be diagnosed in this population without objective confirmation with cognitive testing.
    Archives of Clinical Neuropsychology 14(6):531-536. · 2.18 Impact Factor