Biomedical subjects

Barbara L Schwartz

Publications and source records attributed to Barbara L Schwartz.

12 recordsLinked to original sources

PubMed2006

Imitation of facial expressions in schizophrenia.

Diminished facial expressivity is a common feature of schizophrenia that interferes with effective interpersonal communication. This study was designed to determine if real-time visual feedback improved the ability of patients with schizophrenia to imitate and produce modeled facial expressions. Twenty patients with schizophrenia and 10 controls viewed static images of facial expressions and were asked to imitate them. Half of the images were imitated with the use of a mirror and half were imitated without the use of a mirror. In addition, we examined whether practice in imitating and producing expressions improved the ability of participants to generate facial expressions on their own, without the aid of a model or mirror. Participants' facial expressions were photographed with a digital camera and each was rated for accuracy in producing characteristic facial expressions. Patients with schizophrenia were less accurate in imitating and producing facial expressions than controls, and real-time visual feedback did not improve accuracy in either group. Preliminary findings suggest that exposure to model expressions and practice in generating these expressions can improve the accuracy of certain posed expressions in schizophrenia.

Adult↗

PubMed2005

Memory encoding and retrieval on the ascending and descending limbs of the blood alcohol concentration curve.

RATIONALE: Little is known about acute effects of alcohol on memory encoding and retrieval on different limbs (ascending and descending) of the blood alcohol concentration (BAC) curve. OBJECTIVES: This extensive experiment was designed to examine alcohol's effects on memory encoding and retrieval throughout a protracted drinking episode. METHODS: In a 9-h session, male participants consumed either alcohol (1 ml/kg) or placebo (n = 32/32) over a period of 90 min and learned various materials in different memory tasks before, during, and after consuming the drinks, while their BAC levels were monitored. A week later, in a similar session, they were tested on learned materials before, during, and after drinking. Mood was assessed throughout both sessions. RESULTS: Alcohol impaired recall of words more than recognition, and cued recall most severely. Perceptual priming and picture recognition were not affected by alcohol. Alcohol impaired encoding in cued recall, recognition of completed word fragments, and free recall regardless of limb, but impaired retrieval in word recognition only during the ascending BAC. Alcohol increased negative mood on the descending limb during the first session, and on the ascending limb during the second session. CONCLUSIONS: Under naturalistic drinking conditions, alcohol's effects on memory depend on task, memory process, and limb of the BAC curve. The differential effects of alcohol on retrieval during the ascending and descending limbs demonstrate the importance of examining the differential effects on the two limbs.

Adult↗

PubMed2005

Implicit learning of non-spatial sequences in schizophrenia.

Recent studies have reported abnormal implicit learning of sequential patterns in patients with schizophrenia. Because these studies were based on visuospatial cues, the question remained whether patients were impaired simply due to the demands of spatial processing. This study examined implicit sequence learning in 24 patients with schizophrenia and 24 healthy controls using a non-spatial variation of the serial reaction time test (SRT) in which pattern stimuli alternated with random stimuli on every other trial. Both groups showed learning by responding faster and more accurately to pattern trials than to random trials. Patients, however, showed a smaller magnitude of sequence learning. Both groups were unable to demonstrate explicit knowledge of the nature of the pattern, confirming that learning occurred without awareness. Clinical variables were not correlated with the patients' learning deficits. Patients with schizophrenia have a decreased ability to develop sensitivity to regularly occurring sequences of events within their environment. This type of deficit may affect an array of cognitive and motor functions that rely on the perception of event regularity.

Adult↗

PubMed2005

Therapeutic implications of a selective alpha7 nicotinic receptor abnormality in schizophrenia.

A convergence of preclinical pharmacology, and human autopsy and genetic data support the existence of reduced expression and function of the alpha7 nicotinic receptor in patients with schizophrenia. The alpha7 nicotinic receptor is a member of a family of ligand-gated ion channels. The alpha7 nicotinic receptor may play an essential role in auditory sensory gating and voluntary smooth pursuit eye movements, two psychophysiological functions that are abnormal in patients with schizophrenia and closely related unaffected biological relatives. Diminished expression or function of the alpha7 nicotinic receptor in schizophrenia has stimulated consideration of selective full or partial alpha7 nicotinic receptor agonists as possible therapeutic interventions for this disorder. Further, the availability of positive allosteric modulators of nicotinic receptors that can improve the efficiency of transduction of the acetylcholine signal and prevent the rapid desensitization of the receptor should encourage these novel treatment approaches (e.g., galantamine).

Eye Movements↗

PubMed2004

A quantitative measure of postural sway deficits in schizophrenia.

Clinicians rely on observational methods to assess obvious signs of postural abnormalities in schizophrenia, yet subtle signs of postural deficits may go unnoticed. Posture is controlled, in large part, by the cerebellum, which has been implicated in numerous reports of structural and functional deficits in schizophrenia. Given the possibility of an underlying disruption of cerebellar function in schizophrenia, this study used an objective, quantitative measure to assess the magnitude of postural stability in this disorder. A total of 36 schizophrenia patients and 36 non-psychiatric age-matched controls stood on a pressure-sensitive platform that recorded shifts in weight (body sway) through pressure points in the feet. Patients demonstrated more postural sway than did healthy controls (p<0.01). When patients with noticeable signs of tardive dyskinesia were removed from analyses, group differences remained (p<0.01). There was no significant correlation between neuroleptic medication level and degree of postural sway (r=0.16, p=0.37). These results indicate that patients with schizophrenia have subtle, yet quantifiable, disturbances in the control of posture and balance. Quantitative measures of postural sway may provide a more sensitive means of detecting disturbances of movement than do standard clinical observations alone.

Adult↗

PubMed2004

Word production deficits in schizophrenia.

Fronto-cerebellar circuitry is implicated in word production. Data suggest that the cerebellum is involved in word search, whereas the prefrontal cortex underlies the selection of words from among competing alternatives. We explored the role of search and selection processes in word production deficits in schizophrenia patients. In Experiment 1, patients were impaired in a verb generation task under both high and low selection conditions but were more impaired in the high selection condition. In Experiment 2, when the difficulty level of search and selection conditions was equated in a word stem completion task, patients were only impaired in the search condition. Word search deficits underlie word production problems in schizophrenia, and may involve fronto-cerebellar dysfunction.

Adult↗

PubMed2004

Aging, recall and recognition: a study on the sensitivity of the University of Southern California Repeatable Episodic Memory Test (USC-REMT).

This study examines the sensitivity of the University of Southern California Repeatable Episodic Memory Test (USC-REMT) to the effects of aging in a sample of 112 men and women from 18 to 93 years old. Two new recognition measures, yes-no and forced-choice, were developed to supplement the original USC-REMT which measured only free-recall. Free-recall, yes-no recognition and forced-choice recognition were sensitive to age effects, with free-recall being the most sensitive. The seven recall and recognition lists can be used interchangeably. The data indicate that the USC-REMT is worthy of consideration when there is a need for a brief, screening tool of various memory functions, particularly when there is interest in memory changes over time and repeated assessments.

Adolescent↗

PubMed2003

Implicit learning of visuospatial sequences in schizophrenia.

The authors examined whether patients with schizophrenia learned sequential patterns in a probabilistic serial response time task in which pattern trials alternated with random ones. Patients showed faster and more accurate responses to pattern trials than to random trials, but controls showed greater sensitivity to patterns. The highest level of regularity learned in both groups was information about runs of 3 events. Pattern learning occurred largely outside of awareness, as participants could not describe patterns. Controls with higher memory spans learned the sequential pattern better than those with lower memory spans, suggesting that working memory influences implicit pattern learning. Pathology in motor sequencing systems and poor working memory may lead to deficits in learning sequence structure in schizophrenia.

Adult↗

PubMed2002

Source monitoring in alcoholism.

Recent research on the neural bases of source memory suggests that this type of memory is relevant to the neuropsychological assessment of neurobehavioral disorders. Source memory refers to the ability to discriminate the origin or source of information (e.g., did I think of the idea or did I read about it). We examined source monitoring in abstinent alcoholic patients (N = 53) and nonalcoholic controls (N = 34) and report significant impairments in the alcoholic patients' ability to remember the source of recently presented information. Decrements in source memory were uncorrelated with alcoholic patients' neuropsychological deficits on the Wisconsin Card Sorting Test or the Benton Facial Recognition Test. Using qualitative measures of brain CT scans in a subsample of 39 alcoholic patients, we found that source memory was correlated with Sylvian fissure ratings in the left hemisphere. We propose that source memory decrements are another area of neuropsychological functioning affected in chronic alcoholism. Tasks of source memory may offer the neuropsychologist a valuable new tool for evaluating cognitive functions in neurobehavioral disorders.

Adult↗

PubMed2002

Configural processing in face recognition in schizophrenia.

INTRODUCTION: There is currently substantial literature to suggest that patients with schizophrenia are impaired on many face-processing tasks. This study investigated the specific effects of configural changes on face recognition in groups of schizophrenia patients. METHODS: In Experiment 1, participants identified facial expressions in upright faces and in faces inverted from their upright orientation. Experiments 2 and 3 examined recognition memory for faces and other non-face objects presented in upright and inverted orientations. Experiment 4 explored recognition of facial identity in composite images where the top half of one face was fused to the bottom half of another face to form a new face configuration. RESULTS: In each experiment, the configural change had the same effect on face recognition for the schizophenia patients as it did for control participants. Recognising inverted faces was more difficult than recognising upright faces, with a disproportionate effect of inversion on faces relative to other objects. Recognition of facial identity in face-halves was interfered with by the formation of a new face configuration. CONCLUSION: Collectively, these results suggest that people with schizophrenia rely on configural information to recognise photographs of faces.

Journal Article↗

PubMed2002

Fluoxetine's effects on cognitive performance in patients with traumatic brain injury.

OBJECTIVE: There are preclinical data showing that fluoxetine stimulated expression of Brain Derived Neurotrophic Factor (BDNF) and its specific tyrosine kinase receptor, and caused neuritic elongation and increased dendritic branching density of CA3 hippocampal pyramidal cell neurons in rodents. The latter effect of fluoxetine has been referred to as neuronal remodeling. In view of this preclinical data, we wondered if specific cognitive measures could serve as novel therapeutic targets for fluoxetine in head-injured patients. Theoretically, fluoxetine-induced "neuronal remodeling" might improve cognition, independently of a primary effect on mood. METHOD: In an open-label pilot investigation, fluoxetine hydrochloride (Prozac; 20-60 mg/day) was administered to a heterogeneous group of five head-injured patients with either no or moderate depression for a period of eight months. These patients had no histories of prior treatment with antidepressant medications. They were administered cognitive and memory tests at baseline and after eight months of treatment on fluoxetine. RESULTS: The preliminary results showed that fluoxetine improved mood, in addition to improving performance on the Trail Making Test Part A, an attentional-motor speed task, and the letter-number sequencing subtest of the WAIS-III, a measure reflecting "working memory." CONCLUSIONS: Although fluoxetine had beneficial effects on some measures of cognition, more work is needed to connect these improvements with neuronal remodeling.

Aged↗

PubMedDate not supplied

Adjuvant topiramate administration: a pharmacologic strategy for addressing NMDA receptor hypofunction in schizophrenia.

N-methyl-d-aspartate receptor hypofunction (NRH) and its downstream consequences, especially excitotoxicity, may explain the progressive psychosocial deterioration and ventriculomegaly observed in at least some patients with schizophrenia. Topiramate has several properties that address downstream consequences of NRH. In this open-label investigation, the authors examined the salutary therapeutic effects of adjuvant topiramate in 12 patients with schizophrenia and schizoaffective disorder. Patients were selected on the basis of the presence of negative symptoms. An optimal dose of topiramate was determined for each patient during a slow 4-week titration process. Patients were maintained on topiramate and their stable antipsychotic medications for 8 weeks, after which topiramate was tapered and discontinued. Patients were followed for an additional 4 weeks on their stable antipsychotic medications. Clinical measures of efficacy (eg, Positive and Negative Syndrome Scale), cognitive measures (eg, verbal fluency, memory), and safety measures (eg, postural sway) were assessed throughout this study. Topiramate administration (average dose, 110.42 mg/day) decreased total scores on the Positive and Negative Syndrome Scale. Topiramate was also associated with a selective and reversible worsening of verbal fluency performance. These results encourage further testing of topiramate and kainate/alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonists in schizophrenia patients and support the heuristic model of NRH.

Adult↗