Motivated to do well: an examination of the relationships between motivation, effort, and cognitive performance in schizophrenia.

The uncertain relationship between negative symptoms, and specifically motivational deficits, with cognitive dysfunction in schizophrenia is in need of further elucidation as it pertains to the interpretation of cognitive test results. Findings to date have suggested a possible mediating role of motivational deficits on cognitive test measures, although findings from formal examinations of effort using performance validity measures have been inconsistent. The aim of this study was to examine the relationships between motivation, effort exerted during cognitive testing, and cognitive performance in schizophrenia. Sixty-nine outpatients with schizophrenia or schizoaffective disorder were evaluated for psychopathology, severity of motivational deficits, effort exerted during cognitive testing, and cognitive performance. Motivation and degree of effort exerted during cognitive testing were significantly related to cognitive performance, specifically verbal fluency, verbal and working memory, attention and processing speed, and reasoning and problem solving. Further, effort accounted for 15% of the variance in cognitive performance, and partially mediated the relationship between motivation and cognitive performance. Examining cognitive performance profiles for individuals exerting normal or reduced effort revealed significant differences in global cognition, as well as attention/processing speed and reasoning and problem solving. These findings suggest that cognitive domains may be differentially affected by impairments in motivation and effort, and highlight the importance of understanding the interplay between motivation and cognitive performance deficits, which may guide the appropriate selection of symptom targets for promoting recovery in patients.

Facial emotion recognition in borderline personality disorder.

BACKGROUND: Emotion dysregulation represents a core symptom of borderline personality disorder (BPD). Deficits in emotion perception are thought to underlie this clinical feature, although studies examining emotion recognition abilities in BPD have yielded inconsistent findings. Method The results of 10 studies contrasting facial emotion recognition in patients with BPD (n = 266) and non-psychiatric controls (n = 255) were quantitatively synthesized using meta-analytic techniques. RESULTS: Patients with BPD were less accurate than controls in recognizing facial displays of anger and disgust, although their most pronounced deficit was in correctly identifying neutral (no emotion) facial expressions. These results could not be accounted for by speed/accuracy in the test-taking approach of BPD patients. CONCLUSIONS: Patients with BPD have difficulties recognizing specific negative emotions in faces and may misattribute emotions to faces depicting neutral expressions. The contribution of state-related emotion perception biases to these findings requires further clarification.

Prediction of longitudinal functional outcomes in schizophrenia: the impact of baseline motivational deficits.

Emerging evidence suggests that motivational deficits are a central component of negative symptoms in schizophrenia, and linked to functional impairment characterizing this illness. This study extends previous cross-sectional findings by examining the concurrent contributions of baseline motivational deficits, other negative symptoms, and other symptom domains on longitudinal functional outcomes in schizophrenia. Results of this longitudinal examination of 18 patients from our previous pilot study reveal that amotivation accounts for 74% and 72% of the variance in functional outcomes at baseline and 6-month follow-up, respectively. These findings further suggest a fundamental role for motivational deficits in predicting functional outcomes in schizophrenia.

Motivational deficits as the central link to functioning in schizophrenia: a pilot study.

Negative symptoms have consistently been found to contribute to functional impairment in schizophrenia. In this pilot study, we sought to delineate the core negative symptoms that contribute to this functional impairment. Adult outpatients with schizophrenia were evaluated for the severity of positive, negative, cognitive, and depressive symptoms. The Quality of Life Scale was used to assess current functioning. Results from 21 participants revealed that a motivation was the sole predictor of functioning, accounting for 74% of the variance in current functioning. This suggests that motivational deficits are the central link between negative symptoms and functional impairment in schizophrenia.

In vivo neuroanatomy of Alzheimer's disease: evidence from structural and functional brain imaging.

In vivo structural (CT, MRI) and functional (SPECT, PET) brain imaging techniques have been widely used to study the neuroanatomy and neurophysiology of Alzheimer's disease (AD) and to identify definite biological markers of the disease. We used meta-analytic methods to synthesize this literature to determine what neuroanatomical structures best differentiate patients with AD from healthy normal controls. A total of 125 studies published between 1984 and 2000 that included 3543 patients with AD and 1698 normal healthy controls met inclusion criteria. We found that measures of the temporal cortices, including the amygdala, hippocampus, and inferior temporal lobes, along with the anterior cingulate cortex, associated with the largest magnitudes of effects and, hence, could serve as the most useful structures to help clinicians differentiate AD from healthy normal aging.

Evidence for a shrinking span of personal and present existence in dementia of the Alzheimer's type.

Severely impaired episodic memory deprives patients with Alzheimer's disease (AD) of a sense of personal continuity in their daily lives, yet there are no tests that accurately measure this impairment. Recently, Zakzanis, Leach, and Moscovitch (1999) examined the integrity of memory function in terms of temporal continuity in a way that would engage the patient in everyday behavior, such as informal conversation, but still allow memory function to be quantified. The task allowed the measurement of the duration of continuous, conscious experience of the present and was therefore termed "span of temporal continuity (STC)." Given that we were able to document static and growing STCs, we wanted to know whether our measure could track progressive memory loss. Accordingly, we followed a patient we believed was in the very early stages of AD to measure the change of his STC longitudinally. Along with his STC, we present our neuropsychological and brain imaging findings over the course of the investigation.

Executive function in abstinent MDMA ('ecstasy') users.

BACKGROUND: Methylenedioxymethamphetamine (MDMA, or 'Ecstasy') is a growingly popular recreational drug of abuse that is known to damage brain serotonergic neurons in animals and possibly humans. Few functional consequences of MDMA-induced serotonin neurotoxicity have been identified, either in animals or humans. This study sought to determine whether individuals with a history of MDMA use showed evidence of executive dysfunction. MATERIAL AND METHODS: Two groups of young individuals were compared: 24 abstinent MDMA users who had taken MDMA at least once and 24 controls who had never taken MDMA. Each MDMA user completed a questionnaire regarding the characteristics of their MDMA use and all participants completed a questionnaire regarding other recreational drug experience. The Behavioural Assessment of the Dysexecutive Syndrome (BADS) was used to measure executive function in all participants. RESULTS: Evidence of impairment was found on two subtests of the BADS and in terms of a Total Profile Score. In addition, several significant product moment correlations were found suggesting that increases in MDMA consumption may relate to more pronounced impairment in executive function. CONCLUSIONS: Accordingly, MDMA use may be associated with deficits in executive function.

Memory impairment in abstinent MDMA ("Ecstasy") users: a longitudinal investigation.

To examine the neurotoxic potential of continued MDMA ("Ecstasy") use in humans and its functional consequences over the course of 1 year, 15 MDMA users participated in a longitudinal study in which they completed a brief neuropsychological test battery composed mainly of retrospective and prospective memory tasks. Subjects were abstinent for 2 weeks on initial and 1-year testing. Continued use of MDMA was associated with progressive decline in terms of immediate and delayed recall.

Statistics to tell the truth, the whole truth, and nothing but the truth: formulae, illustrative numerical examples, and heuristic interpretation of effect size analyses for neuropsychological researchers.

If, as neuropsychologists, we think of the relationship between brain and behavior as the same as that between truth and reality, we must be equipped with statistical procedures that are coherent in terms of what we measure and what it represents. I believe that this necessary statistical procedure is effect size analysis, and without it, I believe that we fail to tell the truth, the whole truth, and nothing but the truth when describing our neuropsychological research. Accordingly, I review here the standard calculations of commonly employed effect sizes in two group designs and show how to adjust some familiar (and perhaps not so familiar) formulae using illustrative numerical examples. I also put forth an argument to adopt Cohen's measure as an expression of effect size based on its apropos to neuropsychological research. It is also argued that the interpretation of the magnitude of an effect size should depend on context, and not on pre-established heuristic benchmarks. It is noted, however, that effect sizes greater than 3.0 (OL%<5) might seem particularly appropriate when evaluating the sensitivity of neuropsychological tasks and in establishing test markers in neuropsychological disorders.

Posterior cortical atrophy.

BACKGROUND: The term posterior cortical atrophy (PCA) was introduced in 1988 to describe five patients with fairly homogeneous, but otherwise unclassified, symptoms. These patients showed signs of a slowly progressive dementia bearing behavioral and physiologic similarities to Alzheimer's disease, but with notable distinctions. Specifically, PCA is characterized by an early onset of visual agnosia, followed by some or all components of Balint's syndrome, Gerstmann's syndrome, and transcortical sensory aphasia. REVIEW SUMMARY: In this review, the history, epidemiology, pathophysiology, neurobehavioral aspects, assessment (including neurologic and neuropsychologic), differential diagnosis, and treatment recommendations for this disorder are reviewed. CONCLUSIONS: As originally defined, PCA appears to be a clinically homogeneous syndrome. The cluster of symptoms that are common to virtually all examined cases evidences this. Although the behavioral and cognitive properties of the disorder are well established, many aspects of PCA remain unclear. Specifically, available research and understanding of PCA epidemiology and treatment are highly inadequate. In fact, the majority of such information regarding PCA is derived from studies of Alzheimer's disease. To a lesser extent, Pick's disease and Creutzfeldt-Jakob disease research have also provided insight into the underpinnings of PCA. Until PCA is categorically defined as a variant or subgroup of these other neurodegenerative disorders, however, such derivations are merely speculations.

Searching the schizophrenic brain for temporal lobe deficits: a systematic review and meta-analysis.

BACKGROUND: Several empirical studies have found temporal lobe impairments in many patients with schizophrenia. The strength and consistency of this evidence, however, has not been evaluated and synthesized quantitatively. Hence, we ask to what extent are temporal cortices really defective in schizophrenia? METHODS: Meta-analytical methods were used to determine the magnitude of evidence in support of structural and physiological temporal-hippocampal system deficits in schizophrenia. We report effect sizes from studies since 1980 that used structural (CT, MRI) and functional (SPECT, PET) neuroimaging methods. RESULTS: Both structural and functional imaging literatures are distinguished by heterogeneity whereby most patients show normative temporal function and structure, a minority shows diminished values and some patients demonstrate augmented function and structure rather than a deficit. CONCLUSIONS: The findings are hard to incorporate within single disease models that propose major involvement of the temporal system in schizophrenia, at least at the degree of resolution obtained with current imaging technology.

Component analysis of verbal fluency in patients with schizophrenia.

OBJECTIVE: Clustering and-switching components of phonemic fluency performance were compared in patients with schizophrenia and healthy normal controls. BACKGROUND: These components were selected to provide evidence for a specific anatomic locus for the breakdown of language processes or for a multiple-disease model of schizophrenia. METHOD: As part of a larger battery of neuropsychological tests, phonemic fluency tests were administered on an individual basis. On separate 60-second trials, participants were instructed to generate words beginning with the letters C, F, and L, excluding proper names and variants of the same word. Three scores were obtained for each participant: (1) number of words generated, excluding errors and repetitions; (2) mean cluster size; and (3) raw number of switches. RESULTS: The patients showed small but significant impairments in clustering and larger impairments in switching relative to normal controls. CONCLUSIONS: This pattern suggests a relatively greater deficit in functioning in the frontal lobe than in the temporal lobe. However, neither measure was able to completely discriminate patients with schizophrenia from controls. Moreover, differences in fluency performance were observed among subtypes of schizophrenia. Taken together, the findings of impaired performance for both aspects of fluency, differences between subtypes, and the failure to completely discriminate patients with schizophrenia from controls indicate that there is not a single marker of the disease, at least among these fluency variables. Instead, the current findings are more supportive of a multiple-disease model of schizophrenia.

Distinct neurocognitive profiles in multiple sclerosis subtypes.

An effect size analysis was used to review the neuropsychological literature of multiple sclerosis (MS) to determine whether reliable neurocognitive test deficits and differences between chronic-progressive and relapse-remitting subtypes are apparent. Studies dating back to 1983 were gathered and the neuropsychological test results from a total of 1,845 patients with MS, and 1,265 healthy controls, were synthesized using meta-analytic principles. The results indicate that neurocognitive impairment is indeed evident in patients with MS on a number of cognitive tasks and test variables. Secondly, distinct patterns of neurocognitive deficits are evident in chronic-progressive and relapse-remitting subtypes of MS. Finally, relations between neurocognitive impairment and clinical and demographic attributes of patients with MS were revealed.

A neuropsychological comparison of demented and nondemented patients with Parkinson's disease.

The strength and sensitivity of neuropsychological test findings in patients with Parkinson's disease (PD) was reviewed using meta-analytic principles to provide a basis of comparison of deficits in nondemented and demented patients with PD. The review revealed significant relationships among duration of disease, physical disability, and cognitive impairment in nondemented patients, and qualitative and quantitative differences in the pattern of neuropsychological test impairments between nondemented and demented patients with PD. The disparate profiles of neuropsychological impairment in nondemented and demented patients may indeed reflect disease progression in keeping with the significant clinical correlations in nondemented patients. That is, as the duration of the disease endures, it appears that performance on tasks of delayed recall deteriorates first, followed by performance on measures of manual dexterity, cognitive flexibility, and abstraction.

Schizophrenia and the frontal brain: a quantitative review.

Structural and physiological frontal brain system deficits in patients with schizophrenia are reviewed quantitatively. We report effect sizes from studies since 1980 that used structural (CT, MRI), and functional (PET) neuroimaging methods. We found both literatures to be distinguished by heterogeneity whereby most patients show normative frontal function and structure, a minority shows diminished values and some patients demonstrate augmented function and structure rather than deficit. The average magnitude of difference between patients and controls is generally too modest to support the idea that frontal brain dysfunction is a necessary component of schizophrenia. This modesty is most apparent in average effects obtained for frontal brain volume (M = -.36), left frontal brain volume (M = -.16), frontal resting metabolism, and blood flow (M = -.64). Effect sizes of this magnitude imply that schizophrenia and control distributions overlap by as much as 88% and no less than about 60% on frontal brain measures. It is only when behavioral measures are employed as activation tasks during frontal blood flow and metabolism studies, that average effect sizes rise in magnitude to indicate patient-control distribution overlaps that are less than 50%. Overall, the findings are hard to incorporate within single disease models that propose major involvement of the frontal system, at least at the degree of resolution obtained with current imaging technology.

The neuropsychological signature of primary progressive aphasia.

An effect size analysis incorporating meta-analytic principles was used to review neuropsychological findings in patients with primary progressive aphasia (PPA). Studies dating back to 1982 were gathered and the neuropsychological test results from a total of 55 patients with PPA and 162 healthy controls were synthesized using effect size analyses. The results indicate that patients with PPA are most deficient on tests of verbal skill, followed by performance on measures of delayed recall, cognitive flexibility and abstraction, memory acquisition, attention/concentration, and, finally, performance skill. A rank-order list of specific neuropsychological tasks and test variables in order of sensitivity to PPA is also provided to aid in the interpretation of the quantitative results and in the differentiation of PPA from other disorders with prominent features of dementia such as Alzheimer's disease.

Structural and functional meta-analytic evidence for fronto-subcortical system deficit in progressive supranuclear palsy.

Meta-analytic methods were used to determine the most sensitive indexes to fronto-subcortical deficit in progressive supranuclear palsy (PSP) and to further characterize the neurocognitive and related features of PSP that can provide a basis of comparison to other disorders with prominent subcortical brain lesions. Studies dating back to 1984 were gathered and calibrated to compare the neuropsychological, neuroimaging, and neurophysiological test results from 229 patients with PSP, and 357 healthy controls. The tests most sensitive to fronto-subcortical deficit in PSP were mostly neuropsychological measures that include such tests as the Stroop Task, Trail Making Test Part A, and Purdue pegboard performance. We conclude that although neuropsychological measures may be most sensitive to deficits in PSP, they are also less specific and valid indicators of fronto-subcortical brain system integrity.

Brain is related to behavior (p<.05).

This article demonstrates that sole reliance on tests of statistical significance in the analysis and interpretation of neuropsychological data that is grounded in quasi-experimentation can systematically confound the conclusions drawn from our neuropsychological research regarding brain-behavior relations. The conclusion of this article is that we must accompany the statistical significance test with more appropriate statistics--namely, point-estimate effect sizes along with interval estimation and meta-analysis for the analysis of data from multiple studies. The argument for this conclusion is demonstrated from the re-analysis of published neuropsychological test findings. It is recommended on the basis of this review that the consumer of neuropsychological reports will be better served if due consideration is given to the magnitude of effect in brain-behavior statistical analyses.