Publications

@article{parsons_cognitive_2006,

title = {Cognitive sequelae of subthalamic nucleus deep brain stimulation in Parkinson's disease: a meta-analysis},

author = {Thomas D. Parsons and Steven A. Rogers and Alyssa J. Braaten and Steven Paul Woods and Alexander I. Tröster},

url = {http://ict.usc.edu/pubs/Cognitive%20sequelae%20of%20subthalamic%20nucleus%20deep%20brain%20stimulation%20in%20Parkinson%E2%80%99s%20disease-%20a%20meta-analysis.pdf},

year  = {2006},

date = {2006-06-01},

journal = {Lancet Neurology},

volume = {5},

pages = {578--588},

abstract = {Summary: Background Deep brain stimulation of the subthalamic nucleus (STN DBS) is an increasingly common treatment for Parkinson's disease. Qualitative reviews have concluded that diminished verbal fluency is common after STN DBS, but that changes in global cognitive abilities, attention, executive functions, and memory are only inconsistently observed and, when present, often nominal or transient. We did a quantitative meta-analysis to improve understanding of the variability and clinical significance of cognitive dysfunction after STN DBS. Methods: We searched MedLine, PsycLIT, and ISI Web of Science electronic databases for articles published between 1990 and 2006, and extracted information about number of patients, exclusion criteria, confirmation of target by microelectrode recording, verification of electrode placement via radiographic means, stimulation parameters, assessment time points, assessment measures, whether patients were on levodopa or dopaminomimetics, and summary statistics needed for computation of effect sizes. We used the random-effects meta-analytical model to assess continuous outcomes before and after STN DBS. Findings: Of 40 neuropsychological studies identified, 28 cohort studies (including 612 patients) were eligible for inclusion in the meta-analysis. After adjusting for heterogeneity of variance in study effect sizes, the random effects meta-analysis revealed significant, albeit small, declines in executive functions and verbal learning and memory. Moderate declines were only reported in semantic (Cohen's d 0·73) and phonemic verbal fluency (0·51). Changes in verbal fluency were not related to patient age, disease duration, stimulation parameters, or change in dopaminomimetic dose after surgery. Interpretation: STN DBS, in selected patients, seems relatively safe from a cognitive standpoint. However, diffculty in identification of factors underlying changes in verbal fluency draws attention to the need for uniform and detailed reporting of patient selection, demographic, disease, treatment, surgical, stimulation, and clinical outcome parameters.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{parsons_neurocognitive_2006,

title = {Neurocognitive functioning and HAART in HIV and hepatitis C virus co-infection},

author = {Thomas D. Parsons and Karen A. Tucker and Colin D. Hall and Wendy T. Robertson and Joseph J. Eron and Michael W. Fried and R. Kevin Robertson},

url = {http://ict.usc.edu/pubs/Neurocognitive%20functioning%20and%20HAART%20in%20HIV%20and%20hepatitis%20C%20virus%20co-infection.pdf},

year  = {2006},

date = {2006-05-01},

journal = {AIDS},

volume = {20},

pages = {1591--1595},

abstract = {Objectives: This study examined the effects of HAART on neurocognitive functioning in persons with hepatitis C virus (HCV) and HIV co-infection. Design: A prospective study examining neurocognitive performance before and after HAART initiation. Method: Participant groups included a mono-infected group (45 HIV/HCV-participants) and a co-infected group (20 HIV/HCV participants). A neuropsychological battery (attention/concentration, psychomotor speed, executive functioning, verbal memory, visual memory, fine motor, and gross motor functioning) was used to evaluate all participants. After 6 months of HAART, 31 HIV mono-infected and 13 HCV/ HIV co-infected participants were reevaluated. Results: Neurocognitive functioning by domain revealed significantly worse performance in the co-infected group when compared to the monoinfected group on domains of visual memory and fine motor functioning. Assessment of neurocognitive functioning after antiretroviral therapy revealed that the co-infected group was no longer performing worse than the monoinfected group. Conclusions: The findings of the current study suggest that persons with HCV/HIV co-infection may have greater neurocognitive declines than persons with HIV infection alone. HCV/HIV co-infection may accelerate the progression of HIV related neurocognitive decline.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nelson_mmpi-2_2006,

title = {The MMPI-2 Fake Bad Scale: Concordance and Specificity of True and Estimated Scores},

author = {Nathaniel W. Nelson and Thomas D. Parsons and Christopher L. Grote and Clifford A. Smith and James R. Sisung II},

url = {http://ict.usc.edu/pubs/The%20MMPI-2%20Fake%20Bad%20Scale-%20Concordance%20and%20Specificity%20of%20True%20and%20Estimated%20Scores.pdf},

doi = {10.1080/13803390490919272},

year  = {2006},

date = {2006-01-01},

journal = {Journal of Clinical and Experimental Neuropsychology},

volume = {28},

pages = {1--12},

series = {1380-339},

abstract = {A number of recent studies have supported the use of the MMPI-2 Fake Bad Scale (FBS) as a measure of negative response bias, the scale at times demonstrating greater sensitivity to negative response bias than other MMPI-2 validity scales. However, clinicians may not always have access to True FBS (T-FBS) scores, such as when True-False answer sheets are unavailable or published research studies do not report FBS raw scores. Under these conditions, Larrabee (2003a) suggests a linear regression formula that provides estimated FBS (E-FBS) scores derived from weighted validity and clinical T-Scores. The present study intended to validate this regression formula of MMPI-2 E-FBS scores and demonstrate its specificity in a sample of non-litigating, clinically referred, medically intractable epilepsy patients. We predicted that the E-FBS scores would correlate highly (textbackslashtextbackslashtextbackslashtextbackslashtextgreater.70) with the T-FBS scores, that the E-FBS would show comparable correlations with MMPI-2 validity and clinical scales relative to the T-FBS, and that the E-FBS would show an adequate ability to match T-FBS scores using a variety of previously suggested T-FBS raw score cutoffs. Overall, E-FBS scores correlated very highly with T-FBS scores (r = .78, p textbackslashtextbackslashtextbackslashtextbackslashtextless .0001), though correlations were especially high for women (r = .85, p textbackslashtextbackslashtextbackslashtextbackslashtextless .0001) compared to men (r = .62, p textbackslashtextbackslashtextbackslashtextbackslashtextless .001). Thirty-one of 32 (96.9%) comparisons made between E-FBS/T-FBS correlates with other MMPI-2 scales were nonsignificant. When matching to T-FBS "high" and "low" scores, the E-FBS scores demonstrated the highest hit rate (92.5%) through use of Lees-Haley's (1992) revised cutoffs for men and women. These same cutoffs resulted in excellent overall specificity for both the T-FBS scores (92.5%) and E-FBS scores (90.6%). The authors conclude that the E-FBS represents an adequate estimate of T-FBS scores in the current epilepsy sample. Use of E-FBS scores may be especially useful when clinicians conduct the MMPI-2 short form, which does not include all of the 43 FBS items but does include enough items to compute each of the validity and clinical T-Scores. Future studies should examine E-FBS sensitivity in compensation-seekers with incomplete effort.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{parsons_dhea_2006,

title = {DHEA Supplementation and Cognition in Postmenopausal Women},

author = {Thomas D. Parsons and K. M. Kratz and E. Thompson and F. Z. Stanczyk and John Galen Buckwalter},

url = {http://ict.usc.edu/pubs/DHEA%20Supplementation%20and%20Cognition%20in%20Postmenopausal%20Women.pdf},

doi = {10.1080/00207450500341506},

issn = {0020-7454},

year  = {2006},

date = {2006-01-01},

journal = {International Journal of Neuroscience},

volume = {16},

pages = {141--155},

abstract = {Previous work has suggested that DHEA supplementation may have adverse cognitive effects in elderly women. This article analyzed 24-h measurements of DHEA, DHEAS, and cortisol to determine if cognitive decrease with treatment is mediated by DHEA’s impact on endogenous cortisol. It was found that DHEA administration increased cortisol at several hours during the day. In the treatment group, cortisol was positively associated with cognition at study completion. An increase in negative associations between DHEA(S) levels and cognition was found at completion. Increased cortisol does not explain the cognitive deficits associated with DHEA, suggesting a direct negative effect of exogenous DHEA on cognition.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{feintuch_integrating_2006,

title = {Integrating haptic-tactile feedback into a video capture based VE for rehabilitation},

author = {Uri Feintuch and Raz Liat and Jane Hwang and Naomi Josman and Noomi Katz and Rachel Kizony and Debbie Rand and Albert Rizzo and Meir Shahar and Jang Yongseok and Patrice L. (Tamar) Weiss},

url = {http://ict.usc.edu/pubs/Integrating%20Haptic-Tactile%20Feedback%20into%20a%20Video-Capture%E2%80%93Based%20Virtual%20Environment%20for%20Rehabilitation.pdf},

year  = {2006},

date = {2006-01-01},

journal = {CyberPsychology and Behavior},

volume = {9},

number = {2},

pages = {129--132},

abstract = {Video-capture virtual reality (VR) systems are gaining popularity as intervention tools. Todate, these platforms offer visual and audio feedback but do not provide haptic feedback. Wecontend that adding haptic feedback may enhance the quality of intervention for various theoretical and empirical reasons. This study aims to integrate haptic-tactile feedback into avideo capture system (GX VR), which is currently applied for rehabilitation. The proposedmulti-modal system can deliver audio-visual as well as vibrotactile feedback. The latter isprovided via small vibratory discs attached to the patient's limbs. This paper describes thesystem, the guidelines of its design, and the ongoing usability study.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{robertson_thoughts_2006,

title = {Thoughts of death and suicidal ideation in nonpsychiatric human immunodeficiency virus seropositive individuals},

author = {R. Kevin Robertson and Thomas D. Parsons and Charles Horst and Colin D. Hall},

url = {http://ict.usc.edu/pubs/THOUGHTS%20OF%20DEATH%20AND%20SUICIDAL%20IDEATION%20IN%20NONPSYCHIATRIC%20HUMAN%20IMMUNODEFICIENCY%20VIRUS%20SEROPOSITIVE%20INDIVIDUALS.pdf},

doi = {10.1080/07481180600614435},

issn = {0748-1187},

year  = {2006},

date = {2006-01-01},

journal = {Death Studies},

volume = {30},

pages = {455--469},

abstract = {The present study examines the prevalence of death thoughts and suicidality in HIV infection. Subjects (n = 246) were examined for psychiatric morbidity and suicidality. Compared to high risk HIV seronegatives, HIV seropositives (HIV•) had significantly increased frequency and severity of both suicidal ideation and death thoughts. Two-thirds of seropositives had suicidal ideation at some point; half of the seropositives reported suicide plans and one quarter suicide attempts; and third of seropositives reported current suicidal ideation. Suicidal ideation did not increase with advancing disease. The high prevalence of suicidal ideation suggests inclusion of its assessment in HIV treatment regardless of stage.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{gold_effectiveness_2006,

title = {Effectiveness of Virtual Reality for Pediatric Pain Distraction during IV Placement},

author = {Jeffrey I. Gold and Seok Hyeon Kim and Alexis J. Kant and Michael H. Joseph and Albert Rizzo},

url = {http://ict.usc.edu/pubs/Effectiveness%20of%20Virtual%20Reality%20for%20Pediatric%20Pain%20Distraction%20during%20IV%20Placement.pdf},

year  = {2006},

date = {2006-01-01},

journal = {CyberPsychology and Behavior},

volume = {9},

number = {2},

pages = {207--212},

abstract = {The objective of this study was to test the efficacy and suitability of virtual reality (VR) as apain distraction for pediatric intravenous (IV) placement. Twenty children (12 boys, 8 girls) requiring IV placement for a magnetic resonance imaging/computed tomography (MRI/CT) scan were randomly assigned to two conditions: (1) VR distraction using Street Luge(5DT), presented via a head-mounted display, or (2) standard of care (topical anesthetic) with no distraction. Children, their parents, and nurses completed self-report questionnaires that assessed numerous health-related outcomes. Responses from the Faces Pain Scale–Revisedindicated a fourfold increase in affective pain within the control condition; by contrast, nosignificant differences were detected within the VR condition. Significant associations between multiple measures of anticipatory anxiety, affective pain, IV pain intensity, and measures of past procedural pain provided support for the complex interplay of a multimodalassessment of pain perception. There was also a sufficient amount of evidence supportingthe efficacy of Street Luge as a pediatric pain distraction tool during IV placement: an adequate level of presence, no simulator sickness, and significantly more child-, parent-, and nurse-reported satisfaction with pain management. VR pain distraction was positively endorsed by all reporters and is a promising tool for decreasing pain, and anxiety in childrenundergoing acute medical interventions. However, further research with larger sample sizesand other routine medical procedures is warranted.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{braaten_neurocognitive_2006,

title = {Neurocognitive Differential Diagnosis of Dementing Diseases: Alzheimers Demntia, Vascular Dementia, Frontotemporal Dementia, and Major Depressive Disorder},

author = {Alyssa J. Braaten and Thomas D. Parsons and Robert McCue and Alfred Sellers and William J. Burns},

url = {http://ict.usc.edu/pubs/NEUROCOGNITIVE%20DIFFERENTIAL%20DIAGNOSIS%20OF%20DEMENTING%20DISEASES-%20ALZHEIMER%E2%80%99S%20DEMENTIA,%20VASCULAR%20DEMENTIA,%20FRONTOTEMPORAL%20DEMENTIA,%20AND%20MAJOR%20DEPRESSIVE%20DISORDER.pdf},

year  = {2006},

date = {2006-01-01},

journal = {International Journal of Neuroscience},

volume = {116},

pages = {1271--1293},

abstract = {Similarities in presentation of Dementia of Alzheimer's Type, Vascular Dementia, Frontotemporal Dementia, and Major Depressive Disorder, pose differential diagnosis challenges. The current study identifies specific neuropsychological patterns of scores for Dementia of Alzheimer's Type, Vascular Dementia, Frontotemporal Dementia, and Major Depressive Disorder. Neuropsychological domains directly assessed in the study included: immediate memory, delayed memory, confrontational naming, verbal fluency, attention, concentration, and executive functioning. The results reveal specific neuropsychological comparative profiles for Dementia of Alzheimer's Type, Vascular Dementia, Frontotemporal Dementia, and Major Depressive Disorder. The identification of these profiles will assist in the differential diagnosis of these disorders and aid in patient treatment.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{parsons_better_2006,

title = {Better quality of life with neuropsychological improvement on HAART},

author = {Thomas D. Parsons and Alyssa J. Braaten and Colin D. Hall and R. Kevin Robertson},

url = {http://ict.usc.edu/pubs/Better%20quality%20of%20life%20with%20neuropsychological%20improvement%20on%20HAART.pdf},

year  = {2006},

date = {2006-01-01},

journal = {Health and Quality of Life Outcomes},

volume = {4},

number = {11},

abstract = {Background: Successful highly active antiretroviral therapy (HAART) regimens have resulted in substantial improvements in the systemic health of HIV infected persons and increased survival times. Despite increased systemic health, the prevalence of minor HIV-associated cognitive impairment appears to be rising with increased longevity, and it remains to be seen what functional outcomes will result from these improvements. Cognitive impairment can dramatically impact functional ability and day-to-day productivity. We assessed the relationship of quality of life (QOL) and neuropsychological functioning with successful HAART treatment. Methods: In a prospective longitudinal study, subjects were evaluated before instituting HAART (naïve) or before changing HAART regimens because current therapy failed to maintain suppression of plasma viral load (treatment failure). Subjects underwent detailed neuropsychological and neurological examinations, as well as psychological evaluation sensitive to possible confounds. Re-evaluation was performed six months after institution of the new HAART regimen and/or if plasma viral load indicated treatment failure. At each evaluation, subjects underwent ultrasensitive HIV RNA quantitative evaluation in both plasma and cerebrospinal fluid. Results: HAART successes performed better than failures on measures exploring speed of mental processing (p textbackslashtextbackslashtextbackslashtextbackslashtextless .02). HAART failure was significantly associated with increased self-reports of physical health complaints (p textbackslashtextbackslashtextbackslashtextbackslashtextless .01) and substance abuse (p textbackslashtextbackslashtextbackslashtextbackslashtextless .01). An interesting trend emerged, in which HAART failures endorsed greater levels of psychological and cognitive complaints (p = 06). Analysis between neuropsychological measures and QOL scores revealed significant. correlation between QOL Total and processing speed (p textbackslashtextbackslashtextbackslashtextbackslashtextless .05), as well as flexibility (p textbackslashtextbackslashtextbackslashtextbackslashtextless .05). Conclusion: Our study investigated the relationship between HIV-associated neurocognitive impairment and quality of life. HAART failures experienced slower psychomotor processing, and had increased self-reports of physical health complaints and substance abuse. Contrariwise, HAART successes experienced improved mental processing, demonstrating the impact of successful treatment on functioning. With increasing life expectancy for those who are HIV seropositive, it is important to measure cognitive functioning in relation to the actual QOL these individuals report. The study results have implications for the optimal management of HIV-infected persons. Specific support or intervention may be beneficial for those who have failed HAART in order to decrease substance abuse and increase overall physical health.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{miller_memory_2006,

title = {Memory Improvement with Treatment of Hypothyroidism},

author = {Karen J. Miller and Thomas D. Parsons and Peter C. Whybrow and Katja Herle and Natalie Rasgon and Andre Herle and Dorothy Martinez and Dan H. Silverman and Michael Bauer},

url = {http://ict.usc.edu/pubs/Memory%20Improvement%20with%20Treatment%20of%20Hypothyroidism.pdf},

year  = {2006},

date = {2006-01-01},

journal = {International Journal of Neuroscience},

volume = {16},

number = {8},

pages = {895--906},

abstract = {The consequences of inadequate thyroid hormone availability to the brain and treatment effects of levothyroxine function are still poorly understood. This study prospectively assessed the effects of thyroid replacement therapy on cognitive function in patients suffering from biochemical evidenced, untreated hypothyroidism. Significant effects between the untreated hypothyroid group and control group were limited to verbal memory retrieval. When assessing the effects of 3-month treatment, results revealed that the treated hypothyroid group had significant increased verbal memory retrieval. Results suggest that specific memory retrieval deficits associated with hypothyroidism can resolve after replacement therapy with levothyroxine.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{troster_sodium_2006,

title = {Sodium Amytal Testing and Language},

author = {Alexander I. Tröster and Thomas D. Parsons},

url = {http://ict.usc.edu/pubs/Sodium%20Amytal%20Testing%20and%20Language.pdf},

year  = {2006},

date = {2006-01-01},

journal = {Encyclopedia of Language and Linguistics},

volume = {11},

pages = {500--503},

abstract = {The intracarotid amobarbital test (IAT) was first described by Juhn Wada and thus is often referred to as the 'Wada test.' Wada originally developed this technique to study the interhemispheric spread of epileptiform discharges in patients undergoing unilateral electroconvulsive therapy. Based on his observation that an expressive aphasia resulted when the language dominant hemisphere was injected with amobarbital, he reasoned that this technique might be useful in determining hemispheric language dominance in neurosurgical candidates (and thus minimize speech and language dysfunction in patients undergoing dominant hemisphere surgery).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{woods_statistical_2006,

title = {Statistical Power of Studies Examining the Cognitive Effects of Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease},

author = {Steven Paul Woods and Julie D. Rippeth and Emily Conover and Catherine L. Carey and Thomas D. Parsons and Alexander I. Tröster},

url = {http://ict.usc.edu/pubs/STATISTICAL%20POWER%20OF%20STUDIES%20EXAMINING%20THE%20COGNITIVE%20EFFECTS%20OF%20SUBTHALAMIC%20NUCLEUS%20DEEP%20BRAIN%20STIMULATION%20IN%20PARKINSON%E2%80%99S%20DISEASE.pdf},

doi = {10.1080/13854040500203290},

issn = {1385-4046},

year  = {2006},

date = {2006-01-01},

journal = {The Clinical Neuropsychologist},

volume = {20},

pages = {27--38},

abstract = {It has been argued that neuropsychological studies generally possess adequate statistical power to detect large effect sizes. However, low statistical power is problematic in neuropsychological research involving clinical populations and novel interventions for which available sample sizes are often limited. One notable example of this problem is evident in the literature regarding the cognitive sequelae of deep brain stimulation (DBS) of the subthalamic nucleus (STN) in persons with Parkinson's disease (PD). In the current review, a post hoc estimate of the statistical power of 30 studies examining cognitive effects of STN DBS in PD revealed adequate power to detect substantial cognitive declines (i.e., very large effect sizes), but surprisingly low estimated power to detect cognitive changes associated with conventionally small, medium, and large effect sizes. Such wide spread Type II error risk in the STN DBS cognitive outcomes literature may affect the clinical decision-making process as concerns the possible risk of postsurgical cognitive morbidity, as well as conceptual inferences to be drawn regarding the role of the STN in higher-level cognitive functions. Statistical and methodological recommendations (e.g., meta-analysis) are offered to enhance the power of current and future studies examining the neuropsychological sequelae of STN DBS in PD.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{robertson_timed_2006,

title = {Timed Gait Test: Normative Data for the Assessment of the AIDS Dementia Complex},

author = {R. Kevin Robertson and Thomas D. Parsons and John J. Sidtis and Tina Hanlon Inman and Wendy T. Robertson and Colin D. Hall and Richard W. Price},

url = {http://ict.usc.edu/pubs/Timed%20Gait%20Test-%20Normative%20Data%20for%20the%20Assessment%20of%20the%20AIDS%20Dementia%20Complex.pdf},

doi = {10.1080/13803390500205684},

issn = {1380-3395},

year  = {2006},

date = {2006-01-01},

journal = {Journal of Clinical and Experimental Neuropsychology},

volume = {28},

pages = {1053--1064},

abstract = {The Timed Gait test is a standardized procedure assessing motor dysfunction of lower extremities and gait abnormalities associated with AIDS dementia complex. Heretofore, interpretations of Timed Gait results have been hampered by the lack of normative data. We provide results on this test derived from 1,549 subjects (HIV-seronegatives (HIV-) and seropositives (HIV+) classified according to ADC stage). Timed Gait was found to be a useful screening and assessment tool for evaluating ADC and correlated with clinical ADC staging as well as more extensive structured neurological and neuropsychological evaluations. Analysis of covariance results (with age and education as covariates) revealed symptomatic HIV+(SX) and AIDS groups having significantly slower Timed Gait scores than those in the HIV– and asymptomatic HIV+(ASX) groups. The SX group obtained significantly slower timed gait scores than those in the AIDS group. There was a significant increase in Timed Gait scores with each increase in dementia staging with the HIV- subjects having the fastest mean Timed Gait scores and the HIV+ dementia stage 2+ having the slowest. These normative data should prove useful in both recognition of ADC and treatment response. Given its minimal training requirements, the Timed Gait would have utility in resource limited settings.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{morie_development_2005,

title = {Development of a Data Management Tool for Investigating Multivariate Space and Free Will Experiences},

author = {Jacquelyn Morie and Kumar Iyer and Donat-Pierre Luigi and Josh Williams and Aimee Dozois and Albert Rizzo},

url = {http://ict.usc.edu/pubs/Development%20of%20a%20Data%20Management%20Tool%20for%20Investigating%20Multivariate%20Space%20and%20Free%20Will%20Experiences%20in%20Virtual%20Reality.pdf},

year  = {2005},

date = {2005-09-01},

journal = {Applied Psychophysiology and Biofeedback},

volume = {30},

number = {3},

pages = {319--331},

abstract = {While achieving realism has been a main goal in making convincing virtual reality (VR) environments, just what constitutes realism is still a question situated firmly in the research domain. VR has become mature enough to be used in therapeutic applications such as clinical exposure therapy with some success. We now need detailed scientific investigations to better understand why VR works for these types of cases, and how it could work for other key applications such as training. Just as in real life, it appears that the factors will be complex and multi-variate, and this plethoric situation presents exceptional challenges to the VR researcher. We would not want to lessen VR’s ability to replicate real world conditions in order to more easily study it, however, for by doing so we may compromise the very qualities that comprise its effectiveness. What is really needed are more robust tools to instrument, organize, and visualize the complex data generated by measurements of participant experiences in a realistic virtual world. We describe here our first study in an ongoing program of effective virtual environment research, the types of data we are dealing with, and a specific tool we have been compelled to create that allows us some measure of control over this data. We call this tool Phloem, after the botanical channels that plants use to transport, support and store nutrients.},

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pubstate = {published},

tppubtype = {article}

}