Biomedical subjects

N R Varney

Publications and source records attributed to N R Varney.

At least 19 recordsLinked to original sources

PubMed2001

Quantitative PET findings in patients with posttraumatic anosmia.

OBJECTIVE: To investigate quantitative positron emission tomography (PET) findings, particularly from orbitofrontal cortex, in patients with posttraumatic anosmia. SETTING: Neuropsychology outpatient clinic and university brain imaging center. SUBJECTS: Eleven patients with head injury resulting in severe anosmia and 11 controls matched for age. All 11 head-injured patients had their head injuries at least 2 years before involvement in the study. MEASURES: Regional cerebral glucose metabolism was measured with PET. RESULTS: Quantitative evaluation of PET findings for anosmic patients as a group showed orbitofrontal hypometabolism compared with controls. Decreased activity was also noted in mesial temporal lobe. Activity in subcortical white matter was essentially identical between groups. CONCLUSIONS: Findings strongly suggest that posttraumatic anosmia is closely associated with hypometabolism in the orbitofrontal cortex and the medial prefrontal cortex. The results also underscore the importance of posttraumatic anosmia as a clinical sign of orbitofrontal damage, as has been shown previously with neuroSPECT (single photon emission computed tomography).

Adult↗

PubMed2001

Theta bursts, closed head injury, and partial seizure-like symptoms: a retrospective study.

The purpose of this retrospective, chart-review study was to provide additional information on the clinical correlates ofparoxysmal theta activity on EEG and to further examine the previously proposed relation (Varney, Hines, Bailey, & Roberts, 1992) between episodic symptoms in the context of prior closed-head injury and theta bursts. Allparticipants were veterans receiving their health care at a single, tertiary-care, Veterans Affairs medical center. Compared with patients with normal EEGs (comparison group, n = 30) and nonparoxysmal theta-delta slowing (comparison group, n = 30), consecutive patients with theta bursts (n = 38) were found to have significantly more episodic (ie., partial seizure-like) symptoms documented in their medical records. History of closed-head trauma was also associated with increased reporting of episodic symptoms across all three clinical groups. These findings suggest that, in the presence of theta bursts on EEG, clinicians may wish to interview systematicallyfor episodic, partial seizure-like phenomena, especially when paroxysmal theta activity occurs in the context of prior closed head injury.

Adult↗

PubMed2000

Can head injury patients simulate malingering?

In the past few years, there have been many simulation studies on the efficacy of symptom validation tests. These typically involved nonclinical participants. This line of research was limited because the impact of the experience of head injury was not examined. Researchers failed to understand whether individuals with head injury would feign cognitive deficits on symptom validation tests as well as their nonclinical counterparts did. This study was designed to investigate simulation of memory deficits among the head injured on the Portland Digit Recognition Test (PDRT; Binder, 1993). Head injury patients, with and without corroborated brain damage, and a group of controls were involved to resemble clinical populations. Results showed that false negative rates ranged from 67% to 84% when participants were asked to feign memory difficulty on the PDRT. Head injury patients, regardless of corroboration of brain damage, were equally capable of feigning memory deficits on the PDRT as their nonclinical counterparts. Findings suggest that the additive value of symptom validity tests, such as the PDRT, can be limited for their use as malingering tests.

Adult↗

PubMed2000

Quantitative PET scan findings in carbon monoxide poisoning: deficits seen in a matched pair.

Quantitative positron emission tomography (PET) was utilized to establish the degree and localization of central nervous system dysfunction in 2 adult patients 3 years status postchronic carbon monoxide poisoning. The individual PET scans were compared against a composite scan made up of 32 normals using a z transformation statistical parametric map. Neuropsychological findings indicated marked anterior frontal lobe syndrome in the context of far-above-average intelligence, memory, and language. They also showed manifest frontal symptoms in activities of daily living that resulted in vocational disability in each case. PET analysis revealed substantially decreased metabolism in the orbitofrontal and dorsolateral prefrontal cortex as well as in areas of the temporal lobe for each individual. Individual scans were very similar and consistent with patient's presenting symptoms, and changed life circumstances. This report represents the first quantitative functional neuroimaging study relevant to carbon monoxide poisoning.

Clinical Conference↗

PubMed1998

PET scan findings in a patient with a remote history of exposure to organic solvents.

This is a single-case study employing positron emission tomography (PET) scanning and neuropsychological assessment on a 47-year-old male with a 15-year history of repeated respiratory and dermal exposure to high levels of organic solvents with at least 750 peak exposures (i.e., solvent "intoxication"). At age 43, he presented with neuropsychological symptoms of a solvent encephalopathy and multiple abnormalities in his peripheral neurological examination but had normal MRI and EEG findings. Four years after cessation of exposure to degreasing and solvent chemicals, the patient produced a grossly abnormal PET scan in which frontal, hippocampal, and parietal hypometabolism were particularly noteworthy. During this same 4-year period of nonexposure, modest improvements in neuropsychological testing were noted, along with substantial improvements in partial seizurelike symptoms. Frontal lobe deficits elicited in testing and from collateral interview, however, did not change. Findings suggest that repeated peak exposures to organic solvents m y result in a neurobehaviorally complex solvent syndrome caused by central nervous system damage that is readily apparent on PET scan, even though it is not evident in either imaging technologies. In addition, the case is the first reported in which functional neuroimaging was employed to study a patient with chronic solvent encephalopathy many years after cessation of solvent exposure.

Journal Article↗

PubMed1998

Long-term neuropsychological sequelae of severe burns.

Eight patients who suffered severe burns and protracted periods of amnesia following those burns were evaluated for neuropsychological and neuropsychiatric problems between 6 months and 4 years following their accidents. All were found to have significant problems as evidenced in neuropsychological testing, activities of daily living, and reports from relatives. Findings on these burn patients with postburn amnesia were quite different from those of five burn patients who did not develop amnesia. Problems observed and reported in the burn-amnesia patients appeared to reflect clear neuropathological etiologies, which was not unexpected because their initial amnestic syndromes must also have been the result of significant central nervous system dysfunction. It is recommended that severe burn patients have neuropsychological, psychiatric, and neurological exams as part of routine postburn care.

Clinical Conference↗

PubMed1998

NeuroSPECT findings in patients with posttraumatic anosmia: a quantitative analysis.

OBJECTIVE: To investigate quantitative neuroSPECT findings, particularly from orbital frontal cortex, in patients rendered totally anosmic from head injury. SETTING: Veterans Administration (VA) Medical Center. SUBJECTS: Eighteen patients with head injury resulting in severe anosmia and five normal controls. All 18 patients had sustained their head injuries at least 5 years prior to involvement in the study. MEASURES: Quantitative neuroSPECT (count density) from sagittal regions of interest (ROIs) ranging circumferentially from orbital frontal cortex to occipital pole. RESULTS: Quantitative evaluation of neuroSPECT findings for anosmic patients as a group showed substantial orbital frontal hypoperfusion compared with controls, with 67% of individual anosmic patients showing orbital frontal hypoperfusion at a level two or more standard deviations below that of the worst control subject. By contrast, there were no between-group differences for five other ROIs (inferior frontal pole, superior frontal pole, posterior superior frontal lobe, the parasagittal region, and occipital pole), and individual abnormalities were infrequent in these areas. In addition, orbital frontal count was significantly correlated with ratings of outcome, the only ROI to have such a relationship. CONCLUSIONS: Findings strongly suggest that posttraumatic anosmia and the neuropsychological deficits typically associated with posttraumatic anosmia are closely and specifically associated with hypoperfusion in orbital frontal cortex. The results also underscore the importance of posttraumatic anosmia as a clinical sign of orbital frontal damage, which is particularly important in patients with mild head injury who have normal computed tomography and magnetic resonance imaging scans.

Adult↗

PubMed1997

Neuropsychiatric sequelae of cerebral malaria in Vietnam veterans.

Approximately 250,000 Vietnam veterans suffered cerebral malaria, an illness that often results in damage to subcortical white matter and fronto-temporal areas of neocortex. Case reports dating back 2500 years indicate that survivors of cerebral malaria show depression, poor memory, personality change, and irritability/violence. The purpose of the present study was to compare the neuropsychiatric status of Vietnam veterans who had suffered cerebral malaria in the remote past (i.e., 1966 to 1969) with that of Vietnam veterans wounded in combat who had not suffered malaria or other neurological conditions. Findings indicate that cerebral malaria results in multiple, major, substantially underappreciated neuropsychiatric symptoms in Vietnam veterans, including poor dichotic listening, "personality change," depression, and, in some cases, partial seizure-like symptoms. Findings strongly suggest that history of malaria should be considered in any medical, psychological, or psychiatric workup of a Vietnam War veteran because a positive response could result in substantial changes in diagnosis and treatment.

Adult↗

PubMed1997

Long-term cognitive sequelae of cerebral malaria in Vietnam veterans.

The brains of fatal cases of cerebral malaria exhibit capillary occlusion, punctiform hemorrhages, and focal necrosis in subcortical white matter. Some studies have suggested that the brain pathology of survivors is similar to that of fatal cases. The purpose of this study was to investigate the hypothesis that cerebral malaria survivors would exhibit neuropsychological impairment due to the residual cerebral damage sustained from the infection. Vietnam veterans reporting a history of cerebral malaria were compared with a group of veterans with a history of combat-related injuries on standard neuropsychological tasks and on dichotic listening (DL). The cerebral malaria group performed worse on memory tasks and exhibited greater clinical impairments on DL, consistent with presumed disruption of subcortical white matter tracts.

Journal Article↗

PubMed1997

A case of reversible steroid dementia.

Psychotropic effects of corticosteroids have been reported since early 1950. Dementia-like cognitive changes in patients undergoing treatment with high doses of corticosteroids were identified in 1984. The clinical presentation of these "steroid dementia" patients mimicked those typical of early Alzheimer's disease. As with psychiatric side effects of corticosteroid use, the "dementia" is reversible. The case presented describes a patient who developed dementia-like cognitive changes and an abnormal EEG as a result of steroid treatment. The case is of interest not only as an example of steroid dementia, but also because it is the first with documented electroencephalographic sequelae and premorbid EEG, CT scan and neuropsychological testing.

Journal Article↗

PubMed1996

Design fluency among normals and patients with closed head injury.

A Design Fluency task was administered to 86 patients who had suffered closed head injury (CHI) with loss of consciousness and 87 normal control subjects. Subjects were asked to draw as many novel designs as they could in 5 minutes without scribbling, drawing a nameable object, or repeating a design that had been drawn previously. The mean performance of the CHI group was significantly poorer than that of the control group, with 47% of head injured performing defectively (below the 5th percentile of controls There was no significant relationship between Design Fluency and prorated IQ, psychomotor speed, or Word Fluency. The findings demonstrate that a standardized version of the "free condition" of Design Fluency is likely to be useful in the evaluation of patients with closed head injury.

Journal Article↗

PubMed1995

Significance of unilateral ear extinction on the dichotic listening test.

The association between unilateral ear extinction on the dichotic listening test and the lateralization of epileptogenic foci was examined in a sample of 49 seizure patients undergoing preoperative evaluation for epilepsy surgery. Results from patients who were left hemisphere dominant for speech indicated that right ear impairment was always predictive of a unilateral left hemisphere focus, but left ear extinction was associated with unilateral lesions of either hemisphere. In this patient sample, dichotic listening performance reflected an interaction of both lateralized foci and hemispheric preference of language processing. Implications concerning clinical use of the dichotic listening test are discussed.

Adolescent↗

PubMed1995

Characteristics and mechanisms of epilepsy spectrum disorder: an explanatory model.

Recently, a complex neurobehavioral disorder with paroxysmal affective, psychosensory, and cognitive symptoms has been described by a number of different neuropsychiatric and neuropsychological practitioners. Although a variety of different terms have been used to characterize this clinical entity, the recently coined term epilepsy spectrum disorder (ESD) will be used for the purposes of this article. The clinical identification, neuropsychological characteristics, differential diagnosis, etiology, and treatment response of such patients will be reviewed. The possible neuropathological and neurophysiological mechanisms underlying ESD and implications for future research will also be discussed It is argued that neuropsychologists should be more familiar with this syndrome because such patients are frequently referred for neuropsychological assessment when practitioners from medical disciplines are confused by the atypical and polysymptomatic clinical presentations of ESD patients.

Journal Article↗

PubMed1995

Brain injury without head injury. Some physics of automobile collisions with particular reference to brain injuries occurring without physical head trauma.

The classic kinematic formula, a=(v2-v0(2))/2s, relating deceleration to change of velocity and displacement during the change, is used to determine the acceleration experienced by the occupants of motor vehicles (and their heads) during collisions. The displacement, s, of the occupants in the accident can often be determined from the deformation of the wreckage, thus yielding this critical information about potential for brain injury. Data from 15 accidents are assembled and approximate accelerations computed. At the same time medical and neuropsychological data have been obtained for each of the accident victims. These accidents and the associated victims (except for one special case) have been selected because in no case has the victim suffered a direct head-contact injury. Nevertheless, all suffered neurologic and/or neuropsychological injuries typical of patients with closed head trauma. The paper demonstrates that with decelerations from 30 g to more than 200 g yet without skull impacts, brain damage results.

Journal Article↗

PubMed1994

Do dichotic word listening asymmetries predict side of temporal lobe seizure onset?

Dichotic word listening asymmetries are thought to be useful in predicting side of temporal lobe dysfunction. However, little direct evidence exists to support this assumption in practice, especially in patients with subtle epileptogenic lesions. To determine if word listening ear asymmetries are valid predictors of side of temporal lobe seizure onset, we examined the preoperative dichotic word listening performance of 80 patients with either left (N = 41) or right (N = 39) temporal lobe (TL) seizure foci. On a group level, patients showed a statistically significant 'lesion effect' as evidenced by a relative deficit in the ear contralateral to the side of lesion. Prediction of side of seizure focus in individual cases, however, was poor: depending upon the criteria used, 61% to 80% of epileptics with unilateral temporal lobe foci did not show the expected contralateral ear deficit. Results suggest that caution be exercised when inferring side of temporal lobe seizure focus through dichotic word listening asymmetries in individual temporal lobe epilepsy cases.

Adult↗

PubMed1994

Long-term neuropsychological sequelae of fever associated with amnesia.

It has been well established that high fever can cause substantial damage to the cerebellum and also cause multiple small vascular lesions in neocortex and subcortical white matter. Beyond acute effects, the neuropsychological sequelae of these latter cortical and subcortical lesions have not been studied. The investigation reported involved 36 VA patients with a history of serious febrile illness. The febrile illnesses of the pyrexic subjects did not cause febrile seizures and resulted from diseases that did not directly involve the brain (e.g., encephalitis, meningitis, malaria). Control subjects were combat veterans who had suffered gunshot wounds, but who had no history of febrile illness. Pyrexic patients performed worse than controls on a variety of measures including language, memory, concentration, and word finding as well as failing a test of dichotic listening for words. Results demonstrate that hyperpyrexia can have lasting neuropsychological sequelae, and suggest that history of serious febrile illness be considered as an exclusionary criterion for participation in neuropsychological research concerning other topics or disorders.

Journal Article↗

PubMed1993

Neuropsychologic dysfunction in women following leuprolide acetate induction of hypoestrogenism.

OBJECTIVE: The study investigated the neuropsychological status of women with induced hypoestrogenism. DESIGN: An ABA design was employed in which neuropsychological measures were repeated prior to, during, and after induction of hypoestrogenism with leuprolide acetate. SETTING: The study took place in a medical school affiliated in vitro fertilization clinic. INTERVENTIONS: Leuprolide acetate was administered to all subjects as part of in vitro fertilization. METHODS: Eighteen women receiving in vitro fertilization treatment underwent neuropsychological testing before, during, and after treatment with leuprolide acetate and gonadotrophins. The neuropsychological test battery was selected on the basis of previous patients' symptomatic complaints during periods of hypoestrogenism with leuprolide acetate. RESULTS: Depending upon the tests administered, some individuals showed significant cognitive deficits during therapy particularly in the areas of memory, fine motor coordination, and two-point discrimination. Two of the 18 subjects showed very substantial neuropsychological sequelae including memory gaps and disturbances in a variety of neuropsychological test performances. However, in terms of group statistics, only two-point discrimination and delayed recall memory test performance proved significant. Not all measures were sensitive for the group, as many tests displayed a balance between individuals who showed practice effects and those who showed detrimental effects. CONCLUSIONS: For a substantial portion of individuals, hypoestrogenism can result in statistically significant or clinically noteworthy problems with memory, dexterity, and two-point discrimination.

Adult↗

PubMed1993

Identification of treatment-resistant depressives who respond favorably to carbamazepine.

Thirteen depressed patients with documented histories of failure to respond to tricyclic antidepressant medications who reported multiple partial seizure like symptoms were given open trials of carbamazepine. Eleven of the 13 showed moderate to substantial improvement in affective status that was accompanied by significant mean changes on the Beck or Hamilton depression scales. In addition, the mean number of reported partial seizure-like symptoms decreased significantly with treatment. Dichotic word listening performance was the only neuropsychological variable that was impaired at baseline and was also the only cognitive performance that improved following treatment. These preliminary observations suggest that there is likely to be a subgroup of treatment-resistant, carbamazepine-responsive depressives who can be identified by evaluating for the presence of multiple partial seizure-like symptoms.

Adult↗