Impaired cue identification and intention retrieval underlie prospective memory deficits in patients with first-episode schizophrenia

Further clarification of cognitive processes of prospective memory in schizophrenia by comparing eye-tracking and ecologically-valid measurements

The aim of this study is to compare ecologically-valid measure (the Cambridge Prospective Memory Test, CAMPROMPT) and laboratory measure (eye-tracking paradigm) in assessing prospective memory (PM) in individuals with schizophrenia spectrum disorders (SSDs). In addition, eye-tracking indices are used to examine the relationship between PM and other cognitive domains in SSDs patients. Initially, the study sample was formed by 32 SSDs patients and 32 healthy control subjects (HCs) who were matched in sociodemographic profile and the performance on CAMPROMPT. An eye-tracking paradigm was employed to examine the differences in PM accuracy and key cognitive processes (e.g., cue monitoring) between the two groups. Additional 31 patients were then recruited to investigate the relationship between PM cue monitoring, other cognitive functions, and the severity of clinical symptoms within the SSDs group. The monitoring of PM cue was reflected in total fixation time and total fixation counts for distractor words. Cognitive functions were assessed using the Chinese version of the MATRICS Consensus Cognitive Battery (MCCB). The Positive and Negative Syndrome Scale (PANSS) was applied to assess psychopathology. SSDs patients exhibited fewer total fixation counts for distractor words and lower PM accuracy compared to HCs, even though they were priori matched on CAMPROMPT. Correlation analysis within the SSDs group (63 cases) indicated a negative correlation between PM accuracy and PANSS total score, and a positive correlation with working memory and attention/vigilance. Regression analysis within the SSDs group revealed that higher visual learning and lower PANSS total scores independently predicted more total fixation counts on distractor words. Impairment in cue monitoring is a critical factor in the PM deficits in SSDs. The eye-tracking laboratory paradigm has advantages over the ecologically-valid measurement in identifying the failure of cue detection, making it a more sensitive tool for PM deficits in patients with SSDs.

The deficient cue monitoring and the facilitating effect of prosocial intention on prospective memory in patients with schizophrenia spectrum disorders

The study aimed to investigate the cognitive processing of prospective memory (PM) in patients with schizophrenia spectrum disorders (SSDs) by using an eye-tracking paradigm. In addition, the facilitating effects of prosocial intention (the desire to help others) on PM in SSDs were also examined. In phase 1, 26 patients (group1) and 25 healthy controls (HCs) were compared in an eye-tracking PM paradigm in terms of the PM accuracy and eye-tracking indices. In phase 2, 21 more patients (group2) were recruited, and a prosocial intention was introduced in the eye-tracking PM paradigm. Their PM accuracy and eye-tracking indices were compared with those in group1. The PM cue monitoring was indicated by the total fixation counts and fixation time on distractor words. In phase 1, group1 showed lower PM accuracy, fewer fixation counts and less fixation time on distractor words than HCs. In phase 2, group2 (with prosocial intention) performed significantly better than group1 (with typical instruction) on both PM accuracy and fixation time on distractor words. In both groups of SSDs, the PM accuracy was significantly correlated with both the fixation counts and the fixation time of distractor words. After controlling for the cue monitoring indices, the difference in PM accuracy remained significant between group1 and HCs but disappeared between group1 and group2. The cue monitoring deficit contributes to the PM impairment in SSDs. The facilitating effect of prosocial intention disappears after the control of cue monitoring, also indicating its critical role in PM.

Correlation of neurocognitive deficits with positive and negative symptoms in schizophrenia

BACKGROUND

Patients with schizophrenia manifests a broad array of cognitive impairments, including impaired performance on measures reflecting attention, information processing, executive functions, memory, and language capabilities.

AIM

This study aims to assess neurocognitive deficits and their correlation with positive and negative symptoms in patients with schizophrenia.

MATERIALS AND METHODS

Sample was collected from private clinic of Jabalpur, Bhopal, and Patna. Selection of sample was purposive sampling. The sample size consists of 60 diagnosed cases of schizophrenia on the basis of (International Classification of Diseases-10 [ICD-10] Diagnostic Criteria for Research criteria) and 30 normal controls. Annet's Hand Preference Battery was used to screen handedness and only right-handed male were included in this study. After screening according to inclusion and exclusion criteria, 60 diagnosed (ICD-10 criteria) schizophrenia patients were selected which was further divided into two groups on the basis of positive and negative syndrome scale, i.e. schizophrenia with positive and negative symptoms. Thirty matched normal controls having scores <2 scores on General Health Questionnaire-12 were selected for the study. After filling of sociodemographic details Luria-Nebraska Neuropsychological Battery (LNNB-I) was administered on both schizophrenia group and normal control.

RESULTS

Cognitive functions are severely impaired in schizophrenia compared to normal control and within schizophrenia groups negative schizophrenia had poor performance on LNNB-I than positive schizophrenia. Regarding the correlation of neurocognitive deficits, both schizophrenia groups were correlated but negative symptoms of schizophrenia were strongly correlated with neurocognitive deficits.

CONCLUSION

Cognitive functions are severely impaired in schizophrenia as compared to normal control and within schizophrenia groups, negative schizophrenia had poor performance on LNNB-I than positive schizophrenia. Regarding the correlation of neurocognitive deficits, both schizophrenias groups were correlated but negative symptoms of schizophrenia were strongly correlated with neurocognitive deficits.

Prospective memory in non-psychotic first-degree relatives of patients with schizophrenia: a meta-analysis

Prospective memory (PM) could be impaired in the non-psychotic first-degree relatives of patients with schizophrenia. This meta-analysis systematically examined the PM of non-psychotic first-degree relatives of patients with schizophrenia. Both Chinese and English databases were systematically searched for articles from the inception of the databases through November 13, 2018. Case-control studies of PM in non-psychotic first-degree relatives of patients with schizophrenia were included in the analyses. Confidence intervals (CIs) and standardized mean differences (SMDs) were calculated utilizing the random effects model. Four studies (n=268) that compared PM performance between non-psychotic first-degree relatives of patients with schizophrenia (n=136) and healthy controls (n=132) were included. Three studies were rated as "high quality", while the quality of evidence of the three outcomes included in this meta-analysis was moderate. Compared with the healthy controls, the non-psychotic first-degree relatives of patients with schizophrenia showed impairments in overall PM (two studies, n=127; SMD: -0.46; 95% CI=-0.82, -0.11, P=0.01; I=0%), event-based PM (EBPM) (four studies, n=268; SMD: -0.56; 95% CI=-0.80, -0.31, P<0.00001; I=0%), and time-based PM (TBPM) (four studies, n=268; SMD: -0.66; 95% CI=-0.90, -0.41, P<0.00001; I=0%). This meta-analysis demonstrated that the overall PM, EBPM, and TBPM might be impaired in the non-psychotic first-degree relatives of patients with schizophrenia.

Cognitive Deficits in Psychotic Disorders: A Lifespan Perspective

Individuals with disorders that include psychotic symptoms (i.e. psychotic disorders) experience broad cognitive impairments in the chronic state, indicating a dimension of abnormality associated with the experience of psychosis. These impairments negatively impact functional outcome, contributing to the disabling nature of schizophrenia, bipolar disorder, and psychotic depression. The robust and reliable nature of cognitive deficits has led researchers to explore the timing and profile of impairments, as this may elucidate different neurodevelopmental patterns in individuals who experience psychosis. Here, we review the literature on cognitive deficits across the life span of individuals with psychotic disorder and psychotic-like experiences, highlighting the dimensional nature of both psychosis and cognitive ability. We identify premorbid generalized cognitive impairment in schizophrenia that worsens throughout development, and stabilizes by the first-episode of psychosis, suggesting a neurodevelopmental course. Research in affective psychosis is less clear, with mixed evidence regarding premorbid deficits, but a fairly reliable generalized deficit at first-episode, which appears to worsen into the chronic state. In general, cognitive impairments are most severe in schizophrenia, intermediate in bipolar disorder, and the least severe in psychotic depression. In all groups, cognitive deficits are associated with poorer functional outcome. Finally, while the generalized deficit is the clearest and most reliable signal, data suggests specific deficits in verbal memory across all groups, specific processing speed impairments in schizophrenia and executive functioning impairments in bipolar disorder. Cognitive deficits are a core feature of psychotic disorders that provide a window into understanding developmental course and risk for psychosis.

Prospective memory in bipolar disorder: A meta-analysis

There are conflicting findings about prospective memory (PM) performance in bipolar disorder. This meta-analysis systematically examined PM in patients with bipolar disorders. Articles were systematically searched in both English and Chinese databases, from their inception to Nov 15, 2016. Only case-control studies on PM in bipolar patients were included for analyses. The random effect model was used in all meta-analytic outcomes. Four studies (n = 390) comparing PM performance between patients with bipolar disorder (n = 208) and healthy controls (n = 182) were included. Three studies were rated as "high quality", while the quality of evidence in 3 meta-analyzable outcomes ranged from "moderate" (67%) to "high" (33%). Compared to healthy controls, bipolar disorder patients showed impairments in overall PM [2 studies, n = 196; SMD: - 1.08 (95%CI: - 1.61, - 0.55), P < 0.0001; I² = 65%], event-based PM [4 studies, n = 367; SMD: - 0.51 (95%CI: - 0.78, - 0.23), P = 0.0003; I² = 37%] and time-based PM performance [4 studies, n = 367; SMD: - 0.82 (95%CI: - 1.11, - 0.52), P < 0.0001; I² = 41%]. In this meta-analysis, both time-based PM and event-based PM deficits appeared to be evident in bipolar disorder.