Feasibility of application-based psychomotor vigilance testing to assess fatigue in doctors working night shifts and correlation with smartwatch assessed shift intensity.

OBJECTIVES: To assess: (1) the feasibility of novel data collection methods (wearable technology and an application-based psychomotor vigilance test (PVT)), (2) the impact of night shift working on fatigue, both objective and perceived, for doctors working night shifts in acute hospital specialties and (3) the effects of shift intensity and naps obtained on participant fatigue. METHODS: We adopted an innovative, multimodal approach to data collection allowing assessment of objective and perceived measures of fatigue, in addition to markers of shift intensity. This comprised 5 min PVT for objective quantification of fatigue (via the validated, smartphone-based NASA PVT+ application), wearable electronic devices (Fitbit Versa2) for assessment of shift intensity (step counts and active minutes) and questionnaires to elicit perceptions of fatigue and shift intensity. RESULTS: Data was collected from 25 participants for a total of 145 night shifts. Objective fatigue (assessed by PVT performance) was significantly increased post night shift, with a PVT mean reaction time 257 ms pre shift versus 283 ms post shift (p<0.0001). However, differences in PVT pre and post shift were not affected by night shift intensity, nor breaks or naps taken on shift. Differences in psychomotor performance between doctors working in different specialties were also observed. CONCLUSIONS: The data collection methods used were found to be feasible with good participant engagement. Findings support existing evidence that night shift working in healthcare workers is associated with fatigue, with psychomotor impairment observed post shift. Lower shift intensity and napping did not appear to mitigate this effect.

Comparing the Salzmann Index to automatic qualifying conditions when selecting medically necessary orthodontic patients.

INTRODUCTION: This study compared the Salzmann Index (SI) to the American Association of Orthodontists-proposed Automatic Qualifying Conditions (AQC) list in determining eligibility for medically necessary orthodontic care (MNOC). In Pennsylvania, The SI must reflect a score of ≥25, whereas the AQCs are considered binary indicators of a treatment need-the presence of any AQC qualifies a patient for treatment under Medicaid. This study was designed to determine whether the same patients are selected as eligible for MNOC regardless of which selection method is used. METHODS: The orthodontic records of 139 participants aged 10-17 years were used to calculate SI scores and identify any AQCs present. McNemar's test of agreement was used to compare patients selected for treatment needs on the basis of SI to those selected on the basis of the presence of an AQC. RESULTS: The mean SI score was 14.7. Twelve patients (8.6%) were selected for treatment needs because of an SI of ≥25, whereas 44 patients (31.7%) were deemed to have at least 1 AQC present. Of the 44 patients with AQCs, only 11 had SI scores of ≥25. McNemar's test of agreement found that SI score and AQC presence did not select patients similarly (P <0.001). CONCLUSIONS: The SI and AQCs do not appear to select the same patients for MNOC, suggesting that replacing the SI with a list of AQCs would significantly impact which patients are selected for Medicaid-funded orthodontic care in Pennsylvania.

Uncovering the burden of hidden ciliopathies in the 100 000 Genomes Project: a reverse phenotyping approach.

BACKGROUND: The 100 000 Genomes Project (100K) recruited National Health Service patients with eligible rare diseases and cancer between 2016 and 2018. PanelApp virtual gene panels were applied to whole genome sequencing data according to Human Phenotyping Ontology (HPO) terms entered by recruiting clinicians to guide focused analysis. METHODS: We developed a reverse phenotyping strategy to identify 100K participants with pathogenic variants in nine prioritised disease genes (BBS1, BBS10, ALMS1, OFD1, DYNC2H1, WDR34, NPHP1, TMEM67, CEP290), representative of the full phenotypic spectrum of multisystemic primary ciliopathies. We mapped genotype data 'backwards' onto available clinical data to assess potential matches against phenotypes. Participants with novel molecular diagnoses and key clinical features compatible with the identified disease gene were reported to recruiting clinicians. RESULTS: We identified 62 reportable molecular diagnoses with variants in these nine ciliopathy genes. Forty-four have been reported by 100K, 5 were previously unreported and 13 are new diagnoses. We identified 11 participants with unreportable, novel molecular diagnoses, who lacked key clinical features to justify reporting to recruiting clinicians. Two participants had likely pathogenic structural variants and one a deep intronic predicted splice variant. These variants would not be prioritised for review by standard 100K diagnostic pipelines. CONCLUSION: Reverse phenotyping improves the rate of successful molecular diagnosis for unsolved 100K participants with primary ciliopathies. Previous analyses likely missed these diagnoses because incomplete HPO term entry led to incorrect gene panel choice, meaning that pathogenic variants were not prioritised. Better phenotyping data are therefore essential for accurate variant interpretation and improved patient benefit.

Relationship of 3 indexes of orthodontic treatment need used by Medicaid and oral health-related quality of life.

INTRODUCTION: This study aimed to assess the relationship between 3 indexes of orthodontic treatment need that are used by Medicaid, namely the Salzmann Index (SI), the handicapping labiolingual deviation (HLD) Index, and the HLD California Modification Index, and oral health-related quality of life (OHRQOL). METHODS: The orthodontic records of 100 participants aged 11-14 years were used to calculate occlusal index scores. The condition-specific oral impacts on daily performances (OIDP) index questionnaire was used to quantify OHRQOL and to identify detriments attributable to malocclusion-related conditions (MRCs). The relationship between occlusal index scores and OHRQOL was analyzed using descriptive statistics, Spearman rank-order and biserial correlations, and logistic regression. RESULTS: The mean index scores were: SI, 15.4; HLD, 13.2; and HLD California Modification, 15.8. Ninety percent of participants did not have normative orthodontic treatment need according to current index criteria. OIDP scores were not normally distributed, and the mean score was 3.1. Of those participants who reported an impact, 83% attributed at least 1 of those impacts to MRCs; however, 90% of these were of mild or moderate intensity. Smiling was the performance most impacted by MRCs. The only statistically significant correlation between an occlusal index and OIDP scores was for the SI, though this association was weak (r = 0.27). None of the variables used in the logistic regression model (age, sex, 3 index scores) were significant predictors of OHRQOL. CONCLUSIONS: No meaningful association exists between the 3 indexes studied and OHRQOL. These findings challenge the validity of current systems for the allocation of Medicaid-funded orthodontic treatment.

Molecular diagnoses in the congenital malformations caused by ciliopathies cohort of the 100,000 Genomes Project.

BACKGROUND: Primary ciliopathies represent a group of inherited disorders due to defects in the primary cilium, the 'cell's antenna'. The 100,000 Genomes Project was launched in 2012 by Genomics England (GEL), recruiting National Health Service (NHS) patients with eligible rare diseases and cancer. Sequence data were linked to Human Phenotype Ontology (HPO) terms entered by recruiting clinicians. METHODS: Eighty-three prescreened probands were recruited to the 100,000 Genomes Project suspected to have congenital malformations caused by ciliopathies in the following disease categories: Bardet-Biedl syndrome (n=45), Joubert syndrome (n=14) and 'Rare Multisystem Ciliopathy Disorders' (n=24). We implemented a bespoke variant filtering and analysis strategy to improve molecular diagnostic rates for these participants. RESULTS: We determined a research molecular diagnosis for n=43/83 (51.8%) probands. This is 19.3% higher than previously reported by GEL (n=27/83 (32.5%)). A high proportion of diagnoses are due to variants in non-ciliopathy disease genes (n=19/43, 44.2%) which may reflect difficulties in clinical recognition of ciliopathies. n=11/83 probands (13.3%) had at least one causative variant outside the tiers 1 and 2 variant prioritisation categories (GEL's automated triaging procedure), which would not be reviewed in standard 100,000 Genomes Project diagnostic strategies. These include four structural variants and three predicted to cause non-canonical splicing defects. Two unrelated participants have biallelic likely pathogenic variants in LRRC45, a putative novel ciliopathy disease gene. CONCLUSION: These data illustrate the power of linking large-scale genome sequence to phenotype information. They demonstrate the value of research collaborations in order to maximise interpretation of genomic data.

Hepatectomy risk assessment with functional magnetic resonance imaging (HEPARIM).

BACKGROUND: Post hepatectomy liver failure (PHLF) remains a significant risk in patients undergoing curative liver resection for cancer, however currently available PHLF risk prediction investigations are not sufficiently accurate. The Hepatectomy risk assessment with functional magnetic resonance imaging trial (HEPARIM) aims to establish if quantitative MRI biomarkers of liver function & perfusion can be used to more accurately predict PHLF risk and FLR function, measured against indocyanine green (ICG) liver function test. METHODS: HEPARIM is an observational cohort study recruiting patients undergoing liver resection of 2 segments or more, prior to surgery patients will have both Dynamic Gadoxetate-enhanced (DGE) liver MRI and ICG testing. Day one post op ICG testing is repeated and R15 compared to the Gadoxetate Clearance (GC) of the future liver remnant (FLR-GC) as measure by preoperative DGE- MRI which is the primary outcome, and preoperative ICG R15 compared to GC of whole liver (WL-GC) as a secondary outcome. Data will be collected from medical records, biochemistry, pathology and radiology reports and used in a multi-variate analysis to the value of functional MRI and derive multivariant prediction models for future validation. DISCUSSION: If successful, this test will potentially provide an efficient means to quantitatively assess FLR function and PHLF risk enabling surgeons to push boundaries of liver surgery further while maintaining safe practice and thereby offering chance of cure to patients who would previously been deemed inoperable. MRI has the added benefit of already being part of the routine diagnostic pathway and as such would have limited additional burden on patients time or cost to health care systems. (Hepatectomy Risk Assessment With Functional Magnetic Resonance Imaging - Full Text View - ClinicalTrials.gov , n.d.) TRIAL REGISTRATION: ClinicalTrials.gov, ClinicalTrials.gov NCT04705194 - Registered 12th January 2021 - Retrospectively registered.

Corrigendum: Base Rates, Blindness, and Schizophrenia.

[This corrects the article on p. 157 in vol. 4, PMID: 23565104.].

Prevalence and Risk of Violent Ideation and Behavior in Serious Mental Illnesses: An Analysis of 63,572 Patient Records.

Research has consistently demonstrated that people diagnosed with serious mental illness (SMI) are at increased risk for violent ideation and behavior (VIB) and that this is especially the case for SMI patients with comorbid substance use disorders (SUD). Despite this, what is still largely unknown is the relative prevalence of VIB across diagnostic categories, whether the rates of VIB in SMI groups exceed the rates observed in people with SUD only, and which demographic factors increase the likelihood of VIB under different circumstances for people with SMI. To address these questions, we analyzed the intake records of 63,572 patients diagnosed with SMIs (i.e., schizoaffective disorder, schizophrenia, bipolar disorder, and unipolar depression), substance use disorders, and non-SMI psychiatric disorders. Raw prevalence rates for a combined metric of VIB were established and compared for each group, and a series of logistic regression analyses were performed to estimate how various demographic factors influenced the likelihood of VIB endorsement in each study group. Our results revealed that (a) patients with SMI conditions had higher rates of VIB than both patients with non-SMI psychopathology and those with substance use disorders only; (b) patients with SMI and comorbid substance use pathology were responsible for the majority of VIB within each SMI condition; and (c) men with SMI conditions had higher prevalence rates of VIB than females. In addition, we found that for every SMI diagnosis, comorbid substance use disorders and younger age were related to greater risk for VIB, and where race and gender were found to significantly alter the likelihood of VIB endorsement, African American status and female gender were independently related to greater risk. The implications of these findings and directions for future research are discussed.

Flash Electroretinography Parameters and Parkinson's Disease.

BACKGROUND: Parkinson's disease (PD) is known to affect retinal structure and activity. As such, retinal evaluations may be used to develop objective and possibly early PD diagnostic tools. OBJECTIVE: The aim of this study was to investigate the effects of Parkinson's disease (PD) manifestation and treatment on retinal activity. METHODS: Data were collected on 21 participants diagnosed with PD, including the number of medications taken, clinical scales and flash electroretinography (fERG) measurements, under light-adapted and dark-adapted conditions. The fERG parameters measured included a-wave and b-wave amplitude and implicit time (i.e., latency). First, we investigated correlations between symptom measure scores and the fERG parameters. Next, we divided participants into two groups based on their antiparkinsonian medication load and analyzed differences between these groups' fERG parameters. RESULTS: fERG parameters were strongly correlated with a number of clinical variables, including motor and non-motor symptoms and age at PD onset. Photoreceptor cell implicit time was longer among participants taking one or less antiparkinsonian medication as compared to those taking two or more. However, overall there was not strong evidence of a relationship between the number of antiparkinsonian medications taken and the fERG parameters. CONCLUSION: Findings suggest that fERG may be a useful, non-intrusive measure of retinal, and, perhaps overall CNS function, in PD. However, additional studies in larger samples are needed to clarify this association.

Responsiveness to change over time and test-retest reliability of the PROMIS and Neuro-QoL mental health measures in persons with Huntington disease (HD).

BACKGROUND: The majority of persons with Huntington disease (HD) experience mental health symptoms. Patient-reported outcome (PRO) measures are capable of capturing unobservable behaviors and feelings relating to mental health. The current study aimed to test the reliability and responsiveness to self-reported and clinician-rated change over time of Neuro-QoL and PROMIS mental health PROs over the course of a 24-month period. METHODS: At baseline, 12-months, and 24-months, 362 participants with premanifest or manifest HD completed the Neuro-QoL Depression computer adaptive test (CAT), PROMIS Depression short form (SF), Neuro-QoL Anxiety CAT, PROMIS Anxiety SF, PROMIS Anger CAT and SF, Neuro-QoL Emotional/Behavioral Dyscontrol CAT and SF, Neuro-QoL Positive Affect and Well-Being CAT and SF, and Neuro-QoL Stigma CAT and SF. Participants completed several clinician-administered measures at each time point, as well as several global ratings of change at 12- and 24-months. Reliability (test-retest reliability and measurement error) and responsiveness (using standardized response means and general linear models) were assessed. RESULTS: Test-retest reliability and measurement error were excellent for all PROs (all ICC ≥ .90 for test-retest reliability and all SEM percentages ≤ 6.82%). In addition, 12- and 24-month responsiveness were generally supported for the Neuro-QoL and PROMIS mental health PROs; findings relative to clinician-rated anchors of change (e.g., SRMs for the group with declines ranged from .38 to .91 for 24-month change and .09 to .45, with the majority above .25 for 12-month change) were generally more robust than those relative to self-reported anchors of change (e.g., SRMs for the group with declines ranged from .02 to .75, with the majority above .39 for 24-month change and .09 to .45, with the majority above .16 for 12-month change). CONCLUSIONS: The Neuro-QoL and PROMIS mental health PROs demonstrated strong psychometric reliability, as well as responsiveness to self-reported and clinician-rated change over time in people with HD.

Relationships Between Working Alliance and Outcomes in Group Therapy for People Diagnosed with Schizophrenia.

Working alliance (WA) is an important predictor of treatment outcomes in therapy. Forming a strong WA can be challenging with people diagnosed with schizophrenia, and differences between client-rated and clinician-rated WA have been found in this population. This project examined WA in people diagnosed with schizophrenia who completed a skills training and attention shaping group intervention. Paired samples t-tests revealed differences between client and clinician ratings on the Working Alliance Inventory Short Form (WAI-S). Clinician-rated WAI-S scores were related to symptom severity, cognitive functioning, and attention during group sessions. Yet, the primary hypothesis was not supported as WAI-S scores were unrelated to clients' treatment response. Clinician-rated WAI-S was found to partially mediate the relationship between negative symptoms and overall attention. Client-rated WAI-S scores were associated with client measures of self-efficacy and mastery. Results reinforce the importance of working alliance in the treatment of those diagnosed with schizophrenia and indicate clinical and functional factors that may influence the quality of WA.

People with current major depression resemble healthy controls on flash Electroretinogram indices associated with impairment in people with stabilized schizophrenia.

Flash electroretinography (fERG) has been used to identify anomalies in retinal functioning in several psychiatric disorders. In schizophrenia (SCZ), fERG abnormalities are reliably observed, but findings from studies of major depressive disorder (MDD) have been less consistent. In this study, fERG data were recorded from MDD patients in a current major depressive episode (n = 25), and compared to data from SCZ patients (n = 25) and healthy controls (HC; n = 25), to determine the degree to which fERG anomalies in acute MDD overlap or contrast with those observed in stabilized (though not symptom free) SCZ. The primary variables of interest were a-wave (photoreceptor activity), b-wave (bipolar-Müller cell activity), and photopic negative response (PhNR; ganglion cell activity) amplitudes and implicit times. Across most conditions, there were no significant differences between the MDD and HC groups in a- or b-wave response, but the SCZ group consistently demonstrated reduced amplitudes. Interestingly, MDD patients demonstrated an increase in photopic a-wave implicit time relative to SCZ patients, and a decrease in PhNR implicit time relative to controls. Correlations between BDI-II scores and fERG metrics were not significant for either patient group. Overall, these data indicate that, using an fERG protocol that distinguishes SCZ patients from controls, MDD patients experiencing a current depressive episode closely resemble healthy controls in their fERG responses. Therefore, MDD-related fERG changes may be more subtle than those observed in SCZ and detectable only with larger sample sizes than we employed and/or using a different set of fERG test parameters.

Transversus Thoracis Muscle Plane Block.

The transversus thoracis muscle plane block (TTP) block is a newly developed regional anesthesia technique which provides analgesia to the anterior chest wall. Since its introduction, this technique has been utilized for a wide range of surgical procedures as well as nonsurgical indications. Current evidence suggests that the TTP block provides effective analgesia for breast and cardiac surgeries, cardiac device implantation, pericardiocentesis, and acute and chronic pain management. To date, no major complications have been reported. Currently there is an urgent need to standardize the nomenclature of this technique to facilitate accurate communication amongst care providers, researchers, and authors. In this review, we describe the TTP block technique, review the indications and available evidence in clinical practice, and discuss alternative blocks and future prospects.

Smartphone Application as an Education Platform in Hepato-Pancreato-Biliary Surgery.

Background. There are no data to assess the need for smartphone applications (SA) as an educational tool in hepato-pancreato-biliary (HPB) surgery. The primary objective of this study was to assess if SA can be used as an educational tool in HPB surgery. The secondary objective was to assess if SA can help as a decision-making tool for fellowship applicants in HPB surgery. Methods. A preapproved questionnaire was e-mailed by International Hepato-Pancreato-Biliary Association to all its 2350 members. Results. Two hundred seventy-one surgeons responded to the survey. Eight were excluded for incomplete data. A total of 48.7% of responders were between 28 and 43 years old (generation X) and 45.2% between 44 and 62 years old (baby boomers). A total of 37.6% of the responders considered SA as an effective method to teach future trainees, and there were slightly higher odds of choosing SA as a teaching tool if the responder considered themselves as an innovator (odds ratio: 2.24). A total of 87.8% of the responders believe that SA in HPB surgery can be directed toward surgical trainees' education, and 91.6% believed SA can be directed toward a fellow. Ninety-five percent of the responders believed that SA in HPB surgery can possibly help a future applicant to choose an HPB fellowship program. Conclusion. SA can complement other teaching techniques and educational tools in HPB surgery. In addition, it can potentially be used as a platform for HPB surgery fellowship by helping in making a decision regarding appropriate fellowship programs.

Transversus thoracis muscle plane block in cardiac surgery: a pilot feasibility study.

INTRODUCTION: Cardiac surgery patients often experience significant pain after median sternotomy. The transversus thoracis muscle plane (TTP) block is a newly developed, single-shot nerve block technique that provides analgesia for the anterior chest wall. In this double-blind pilot study, we assessed the feasibility of performing this novel block as an analgesic adjunct. METHODS: All patients aged 18-90 undergoing elective cardiac surgery were randomized to the block or standard care control group on admission to the intensive care unit after surgery. Under ultrasound guidance, patients in the block group received the TTP block with 20 mL of either 0.3% or 0.5% ropivacaine bilaterally, based on weight. The control group did not receive any injections. All blocks were performed by a single anesthesiologist, and data collection was performed by blinded assessors. The primary feasibility outcomes were rate of recruitment, adherence, and adverse events. The rate of recruitment was defined as the ratio of patients giving informed consent to the number of eligible patients who were approached to participate. Secondary outcomes included 12-hour and 24-hour Numeric Rating Scale (NRS) pain scores, 24-hour hydromorphone and acetaminophen requirements, time to extubation, time to first opioid administration, and patient satisfaction (on a yes/no questionnaire) at 24 hours. RESULTS: Twenty patients were approached for this study and 19 were enrolled. Eight patients received the intended intervention in each group. The recruitment rate was 95% of all approached eligible patients, and the adherence rate to treatment group was 94%. There were no block-related adverse events. The mean (SD) NRS pain scores at rest were 3.3 (3.2) in the block group vs 5.6 (3.2) in the control group at 12 hours. At 24 hours, the pain scores were 4.1 (3.9) vs 4.1 (3.3) in the block and control group, respectively. The mean (SD) 24-hour hydromorphone administration was 1.9 (1.1) mg in the block group vs 1.8 (0.9) mg in the control group. DISCUSSION: The TTP block is a novel pain management strategy poststernotomy. The results reveal a high patient recruitment, adherence, and satisfaction rate, and provide some preliminary data supporting safety. TRIAL REGISTRATION NUMBER: NCT03128346.

Electroretinographic anomalies in schizophrenia.

Flash electroretinography (fERG) has been used to identify anomalies in retinal cell function in schizophrenia. Several consistent findings have now emerged, but several potentially important parameters have not yet been investigated. In this study, we recorded light- (photopic) and dark-adapted (scotopic) fERG data from 25 schizophrenia patients and 25 healthy control subjects to (1) determine if past key findings on abnormal photoreceptor and bipolar cell signaling could be replicated; (2) for the first time, examine retinal ganglion cell functioning using the photopic negative response of the fERG; (3) also for the first time, determine responsiveness of schizophrenia patients to a flickering stimulus, as an additional method to isolate cone photoreceptor function; and (4) determine if schizophrenia-related changes in the fERG could be detected using a portable hand-held ERG device. In both photopic and scotopic conditions, schizophrenia patients demonstrated weakened photoreceptor and bipolar cell activations that were most pronounced in response to the most intense stimuli. A reduced cone response to a flicker stimulus and attenuation in ganglion cell activity were also observed in the schizophrenia group. In general, groups did not differ in implicit time of retinal cell responses. These findings (1) replicate and extend prior studies demonstrating reduced photoreceptor (both rod and cone) and bipolar cell functioning in schizophrenia; (2) indicate that retinal ganglion function abnormality can also be detected using fERG; and (3) indicate that these anomalies can be detected using a portable testing device, thereby opening up possibilities for more routine administration of ERG testing. (PsycINFO Database Record

Patient, staff, and clinician perspectives on implementing electronic communications in an interdisciplinary rural family health practice.

Aim To conduct an environmental scan of a rural primary care clinic to assess the feasibility of implementing an e-communications system between patients and clinic staff. BACKGROUND: Increasing demands on healthcare require greater efficiencies in communications and services, particularly in rural areas. E-communications may improve clinic efficiency and delivery of healthcare but raises concerns about patient privacy and data security. METHODS: We conducted an environmental scan at one family health team clinic, a high-volume interdisciplinary primary care practice in rural southwestern Ontario, Canada, to determine the feasibility of implementing an e-communications system between its patients and staff. A total of 28 qualitative interviews were conducted (with six physicians, four phone nurses, four physicians' nurses, five receptionists, one business office attendant, five patients, and three pharmacists who provide care to the clinic's patients) along with quantitative surveys of 131 clinic patients. Findings Patients reported using the internet regularly for multiple purposes. Patients indicated they would use email to communicate with their family doctor for prescription refills (65% of respondents), appointment booking (63%), obtaining lab results (60%), and education (50%). Clinic staff expressed concerns about patient confidentiality and data security, the timeliness, complexity and responsibility of responses, and increased workload. CONCLUSION: Clinic staff members are willing to use an e-communications system but clear guidelines are needed for successful adoption and to maintain privacy of patient health data. E-communications might improve access to and quality of care in rural primary care practices.

Seeing more clearly through psychosis: Depth inversion illusions are normal in bipolar disorder but reduced in schizophrenia.

Schizophrenia patients with more positive symptoms are less susceptible to depth inversion illusions (DIIs) in which concave objects appear as convex. It remains unclear, however, the extent to which this perceptual advantage uniquely characterizes the schizophrenia phenotype. To address the foregoing, we compared 30 bipolar disorder patients to a previously published sample of healthy controls (N=25) and schizophrenia patients (N=30). The task in all cases was to judge the apparent convexity of physically concave faces and scenes. Half of the concave objects were painted with realistic texture to enhance the convexity illusion and the remaining objects were untextured to reduce the illusion. Subjects viewed objects stereoscopically or via monocular motion parallax depth cues. For each group, DIIs were stronger with texture than without, and weaker with stereoscopic information than without, indicating a uniformly normal response to stimulus alterations across groups. Bipolar patients experienced DIIs more frequently than schizophrenia patients but as commonly as controls, irrespective of the face/scene category, texture, or viewing condition (motion/stereo). More severe positive and disorganized symptoms predicted reduced DIIs for schizophrenia patients and across all patients. These results suggest that people with schizophrenia, but not bipolar disorder, more accurately perceive object depth structure. Psychotic symptoms-or their accompanying neural dysfunction-may primarily drive the effect presumably through eroding the visual system's generalized tendency to construe unusual or ambiguous surfaces as convex. Because such symptoms are by definition more common in schizophrenia, DIIs are at once state-sensitive and diagnostically specific, offering a potential biomarker for the presence of acute psychosis.

INTERMITTENT DEGRADATION AND SCHIZOTYPY.

Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy) is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-report questionnaires assessing schizotypy and psychological state variables (e.g., anxiety, depression), and their reaction times were recorded as they did so. Intermittent degradation was defined as the number of times a subject's reaction time for questionnaire items met or exceeded three standard deviations from his or her mean reaction time after controlling for each item's information processing load. Intermittent degradation scores were correlated with questionnaire scores. Our results indicate that intermittent degradation is associated with total scores on measures of positive and disorganized schizotypy, but unrelated to total scores on measures of negative schizotypy and psychological state variables. Intermittent degradation is interpreted as potentially derivative of schizotypy and a candidate endophenotypic marker worthy of continued research.