Biomedical subjects

Stefanie M Berns

Publications and source records attributed to Stefanie M Berns.

5 recordsLinked to original sources

PubMed2006

Distinguishing neurocognitive functions in schizophrenia using partially ordered classification models.

Current methods for statistical analysis of neuropsychological test data in schizophrenia are inherently insufficient for revealing valid cognitive impairment profiles. While neuropsychological tests aim to selectively sample discrete cognitive domains, test performance often requires several cognitive operations or "attributes." Conventional statistical approaches assign each neuropsychological score of interest to a single attribute or "domain" (e.g., attention, executive, etc.), and scores are calculated for each. This can yield misleading information about underlying cognitive impairments. We report findings applying a new method for examining neuropsychological test data in schizophrenia, based on finite partially ordered sets (posets) as classification models. A total of 220 schizophrenia outpatients were administered the Positive and Negative Symptom Scale (PANSS) and a neuropsychological test battery. Selected tests were submitted to cognitive attribute analysis a priori by two neuropsychologists. Applying Bayesian classification methods (posets), each patient was classified with respect to proficiency on the underlying attributes, based upon his or her individual test performance pattern. Twelve cognitive "classes" are described in the sample. Resulting classification models provided detailed "diagnoses" into "attribute-based" profiles of cognitive strength/weakness, mimicking expert clinician judgment. Classification was efficient, requiring few measures to achieve accurate classification. Attributes were associated with PANSS factors in the expected manner (only the negative and cognition factors were associated with the attributes), and a double dissociation was observed in which divergent thinking was selectively associated with negative symptoms, possibly reflecting a manifestation of Kraepelin's hypothesis regarding the impact of volitional disturbances on thought. Using posets for extracting more precise cognitive information from neuropsychological data may reveal more valid cognitive endophenotypes, while dramatically reducing the amount of testing required.

Adult↗

PubMed2005

Quantitative craniofacial anomalies in a racially mixed schizophrenia sample.

BACKGROUND: The observation that some patients with schizophrenia display subtly anomalous craniofacial features dates back to the early 1900s and has recently been hypothesized to reflect disrupted prenatal development also involving the brain. Most studies to date have used observer ratings rather than physical measurements and have studied only Caucasian samples. Our objective was to determine whether schizophrenia is associated with craniofacial anomalies applying quantitative methods in Caucasian and African American subjects. METHODS: Participants were 32 Caucasian and 20 African American outpatients aged 18 to 60, meeting Structured Clinical Interview for DSM-IV (SCID) confirmed criteria for schizophrenia/schizoaffective disorder, recently discharged from a psychiatric hospital in Queens, New York. The healthy control subjects were recruited through local advertisements and were individually matched to the patient sample on gender, race, and age. RESULTS: Thirty-two measurements of the head and face reflecting all regions of potential developmental significance were taken according to published methods and validated for this study. Significantly greater skull base width [F(1,51) = 13.11, p = .0005] and greater height of the cutaneous lower lip [F(1,51) = 7.90, p = .0059] were found among patients after applying multiplicity correction. Statistical correction for group differences in body weight did not alter the findings. CONCLUSIONS: Findings agree with the two major anthropometric studies in schizophrenia.

Adolescent↗

PubMed2003

Basic neuropsychological dimensions in schizophrenia.

Neuropsychological (NP) studies in schizophrenia often require data reduction to avoid statistical type I error from multiple comparisons. Typically, this involves grouping measures into domains defined by experts a priori based on delineations validated in brain-injured but not schizophrenia samples (e.g. attention, executive functioning, memory, language visuospatial, motor). Component measures are arbitrarily selected and validity may not generalize to different samples or within the same sample over time. One solution to these problems is illustrated using neurocognitive subdomains based on recent schizophrenia literature, and validated with data from a longitudinal study (156 subjects) involving repeated NP testing (baseline--within 6 months of hospital discharge--and 6 and 18 months later). A priori subdomains were grouped and submitted to principal component analysis (PCA) at each time point. Longitudinal stability of the resulting factors was tested by computing congruency coefficients. Six stable factors were extracted having good construct, divergent and predictive validity. Five neuropsychological measures frequently studied in schizophrenia were not correlated with these factors, suggesting that they should be maintained as independent neurocognitive subdomains. Distinct factors for executive functioning, verbal memory and motor functions could not be validated; this raises concerns about conclusions of previous studies regarding the pattern, severity and correlates of specific neurocognitive functions in schizophrenia.

Adult↗

PubMed2003

The multidimensional scale of independent functioning: a new instrument for measuring functional disability in psychiatric populations.

The Multidimensional Scale of Independent Functioning (MSIF) is a new instrument for rating functional disability in psychiatric outpatients. The MSIF differs from other disability rating scales by providing discrete ratings of (1) role responsibility, (2) presence and level of support, and (3) performance quality. The MSIF, which consists of a semistructured interview and detailed rating anchors, was validated in 114 psychiatric outpatients. The instrument had good criterion, discriminative, interrater, and construct validity. Correlations between comparable ratings on the Social Adjustment Scale II (SAS II) ranged from 0.78 to 0.86. Nevertheless, redundancy analysis using canonical correlation demonstrated that, although the two instruments overlap, the MSIF contains information that is not contained in the SAS II. Furthermore, there was only modest shared variance with conceptually non-overlapping subscales in the SAS II. Interrater reliability (intraclass correlation coefficients) ranged from 0.74 to 1.00 for global and subscale scores. MSIF subscales performed as expected with respect to external validators such as hours of employment, earned income, supported versus nonsupported employment and housing, and mainstream versus nonmainstream educational status. MSIF global ratings were modestly correlated with IQ and psychopathology ratings, consistent with reports in the literature. Construct validity, estimated using Cronbach's alpha coefficient, was 0.72. The MSIF is a promising new instrument designed to circumvent several limitations with existing functional outcome instruments for longitudinal studies, intervention research, and services research.

Demography↗

PubMed1994

On the perceptual organization of speech.

A general account of auditory perceptual organization has developed in the past 2 decades. It relies on primitive devices akin to the Gestalt principles of organization to assign sensory elements to probable groupings and invokes secondary schematic processes to confirm or to repair the possible organization. Although this conceptualization is intended to apply universally, the variety and arrangement of acoustic constituents of speech violate Gestalt principles at numerous junctures, cohering perceptually, nonetheless. The authors report 3 experiments on organization in phonetic perception, using sine wave synthesis to evade the Gestalt rules and the schematic processes alike. These findings falsify a general auditory account, showing that phonetic perceptual organization is achieved by specific sensitivity to the acoustic modulations characteristic of speech signals.

Adult↗