Biomedical subjects

J S Simons

Publications and source records attributed to J S Simons.

8 recordsLinked to original sources

PubMed2002

Memory consolidation and the hippocampus: further evidence from studies of autobiographical memory in semantic dementia and frontal variant frontotemporal dementia.

Studies of autobiographical memory in semantic dementia have found relative preservation of memories for recent rather than remote events. As semantic dementia is associated with progressive atrophy to temporal neocortex, with early asymmetric sparing of the hippocampus, this neuropsychological pattern suggests that the hippocampal complex plays a role in the acquisition and retrieval of recent memories, but is not necessary for the recall of older episodic events. In an alternative view of memory consolidation, however, the hippocampus plays a role in the retrieval of all autobiographical memories, regardless of the age of the memory [Curr. Opin. Neurobiol. 7(1997)217]. This 'multiple trace theory' predicts that patients with semantic dementia should show no effects of time in their autobiographical recall. In this article, we ask whether it is possible to reconcile the data from semantic dementia with the multiple trace theory by investigating whether the time-dependent pattern of autobiographical retrieval seen in the disease is due to (i) patients showing this effect being exceptional in their presentation; and/or (ii) patients with semantic dementia exhibiting impaired strategic retrieval from concomitant frontal damage. A series of experiments in patients with semantic dementia, the frontal variant of frontotemporal dementia and Alzheimer's disease clearly demonstrates that neither of these two factors can explain the documented effect of time seen in semantic dementia. Nonetheless, we discuss how damage to semantic knowledge could result in an autobiographical memory deficit and suggest that data from semantic dementia may be consistent with both views of hippocampal involvement in long-term memory.

Aged↗

PubMed2001

Perceptual and semantic components of memory for objects and faces: a pet study.

Previous studies have suggested differences in the neural substrates of recognition memory when the contributions of perceptual and semantic information are manipulated. In a within-subjects design PET study, we investigated the neural correlates of the following factors: material type (objects or faces), semantic knowledge (familiar or unfamiliar items), and perceptual similarity at study and test (identical or different pictures). There was consistent material-specific lateralization in frontal and temporal lobe regions when the retrieval of different types of nonverbal stimuli was compared, with objects activating bilateral areas and faces preferentially activating the right hemisphere. Retrieval of memories for nameable, familiar items was associated with increased activation in the left ventrolateral prefrontal cortex, while memory for unfamiliar items involved occipital regions. Recognition memory for different pictures of the same item at study and test produced blood flow increase in left inferior temporal cortex. These results have implications for our understanding of the neural correlates of perceptual and semantic contributions to recognition memory.

Adult↗

PubMed2001

Prevalence of sexual dysfunctions: results from a decade of research.

Ten years of research that has provided data regarding the prevalence of sexual dysfunctions is reviewed. A thorough review of the literature identified 52 studies published in the 10 years since an earlier review by Spector and Carey (Arch. Sex. Behav. 19(4): 389-408, 1990). Community samples indicate a current prevalence of 0%-3% for male orgasmic disorder, 0%-5% for erectile disorder, and 0%-3% for male hypoactive sexual desire disorder. Pooling current and 1-year figures provides community prevalence estimates of 7%-10% for female orgasmic disorder and 4%-5% for premature ejaculation. Stable community estimates of the current prevalence of other sexual dysfunctions remain unavailable. Prevalence estimates obtained from primary care and sexuality clinic samples are characteristically higher. Although a relatively large number of studies has been conducted since the earlier review, the lack of methodological rigor of many studies limits the confidence that can be placed in these findings.

Humans↗

PubMed2001

Semantic knowledge and episodic memory for faces in semantic dementia.

Previous studies have documented poor recognition memory for faces in patients with semantic dementia. Preserved face recognition memory was found in this study, however, so long as atrophy was confined predominantly to the left temporal lobe. Patients with structural damage to the right temporal lobe were typically impaired, with the status of the hippocampus and parahippocampal gyrus (including the perirhinal cortex) on the right being critical. Two single-case studies of patients with predominantly left temporal lobe pathology confirmed good recognition memory for famous faces, even if semantic knowledge about the celebrities depicted was severely degraded. An effect of semantic knowledge on recognition memory became apparent only when perceptually different photographs of the famous people were used at study and test. These results support the view that new episodic learning typically draws on information from both perceptual and semantic systems.

Aged↗

PubMed2000

Insights from semantic dementia on the relationship between episodic and semantic memory.

An influential theory of long-term memory, in which new episodic learning is dependent upon the integrity of semantic memory, predicts that a double dissociation between episodic and semantic memory is not possible in new learning. Contrary to this view, we found, in two separate experiments, that patients with impaired semantic memory showed relatively preserved performance on tests of recognition memory if the stimuli were perceptually identical between learning and test. A significant effect of semantic memory was only seen when a perceptual manipulation was introduced in the episodic task. To account for these findings, we propose a revision to current models of long-term memory, in which sensory/perceptual information and semantic memory work in concert to support new learning.

Aged↗

PubMed2000

Treating substance abuse in the context of severe and persistent mental illness: clinicians' perspectives.

Patients with comorbid substance use and major mental disorders are treated frequently in the mental health system. Treatment models relevant for this subset of patients have emerged in recent years, however, few have been validated empirically and so relatively few sites benefit from this treatment development activity. Important additional sources of information about good treatment practices are the clinicians who have adopted the treatment of patients with dual disorders as a specialty. We conducted four focus groups (N = 12) with clinicians who were nominated by their peers as experienced and/or expert in treating persons with comorbid substance use and psychiatric disorders. Discussions followed a four-part outline that included (a) general questions about training and experience with the population, (b) preferred treatment methods, (c) motivational issues, and (d) recommendations to the field. Participants were trained in a variety of mental health disciplines and pursued substance abuse treatment credentials or other educational experiences outside of their primary training programs. Their treatment approaches emphasized psychoeducation, a good therapeutic relationship, and the need to be flexible regarding methods and goals. Abstinence was the preferred goal among most clinicians; even so, they expressed a pragmatic flexibility and other views consistent with the principles of harm reduction. Clinicians tended to respond to patients' ambivalent motivational states by addressing the consequences of behaviors in a nonconfrontive style; they also made use of positive incentives and external support. A number of recommendations were made to improve treatment, including greater institutional and programmatic support for the unique needs of this population.

Adult↗

PubMed2000

Seasonal variations in mood and behavior among Chinese medical students.

OBJECTIVE: The goal of this study was to estimate the frequency of seasonal variations in mood and behavior among Chinese medical students. METHOD: A total of 1,358 medical students were surveyed with Chinese versions of the Seasonal Pattern Assessment Questionnaire and the Beck Depression Inventory in Jining, China. RESULTS: The mean global seasonality score was 8.3 (SD=3.6) out of a possible 24; 81.7% (N=1,110) of the subjects reported some trouble adapting to changing seasons. Summer difficulties were more common than winter difficulties by a ratio of 3:2; estimated rates of summer seasonal affective disorder and subsyndromal seasonal affective disorder were 4.4% and 8.0%, respectively, compared with corresponding winter rates of 2.4% and 5.7%. CONCLUSIONS: These results suggest that seasonal variations in mood and behavior are common in China. The predominance of summer difficulties stands in contrast to that in most Western studies and is consistent with the only other published study performed in Asia.

Adolescent↗

PubMed1996

Concurrent validity of clinicians' ratings of substance abuse among psychiatric outpatients.

OBJECTIVE: Given the prevalence of substance abuse among persons with psychiatric disorders, substance use assessment should be an integral component of mental health evaluations. This study examined the validity of a set of two 5-point rating scales developed for use by mental health clinicians in rating individual clients' levels of alcohol and other drug use. METHODS: A sample of 116 psychiatric outpatients who were participating in a study of psychosocial functioning and substance use was assessed by researchers using an extensive battery of instruments that included the Addiction Severity Index and the Timeline Follow-Back interview. Each client's primary therapist completed the 5-point rating scales to indicate the client's levels of alcohol and drug use. RESULTS: Clients were grouped according to their ratings on the 5-point scales. Significant differences between the groups were found on self-reported patterns of current alcohol and drug use and substance use history. CONCLUSIONS: Outpatient therapists provided ratings of clients' alcohol and drug use that corresponded well with substance use data obtained from an extensive research battery. The study results support use of clinician rating scales as a screening tool for identifying problematic alcohol and other drug use among psychiatric outpatients.

Adult↗