Psychophysiological index during auditory selective attention correlates with visual continuous performance test sensitivity in normal adults

The effects of visual skills training on cognitive and executive functions in stroke patients: a systematic review with meta-analysis

The visual system and associated skills are of particular importance in stroke rehabilitation. The process of neuroplasticity involved in restoring cognitive function during this period is mainly based on anatomical and physiological mechanisms. However, there is little evidence-based knowledge about the effects of visual skills training that could be used to improve therapeutic outcomes in cognitive rehabilitation. A computerized systematic literature search was conducted in the PubMed, Medline, and Web of Science databases from 1 January 1960 to 11 Febuary 2024. 1,787 articles were identified, of which 24 articles were used for the calculation of weighted standardized mean differences (SMD) after screening and eligibility verification. The findings revealed moderate effects for global cognitive function (SMD = 0.62) and activities of daily living (SMD = 0.55) as well as small effects for executive function (SMD = 0.20) - all in favor of the intervention group. The analyses indicate that the results may not be entirely robust, and should therefore be treated with caution when applied in practice. Visual skills training shows positive effects in improving cognitive and executive functions, especially in combination with high cognitive load and in an early phase of rehabilitation. An improvement in activities of daily living can also be observed with this type of intervention. The high heterogeneity of the studies and different treatment conditions require the identification of a relationship between certain visual skills and executive functions in future research.

Cognitive Sequelae of Unruptured and Ruptured Intracranial Aneurysms and their Treatment: Modalities for Neuropsychological Assessment

BACKGROUND

Cognitive sequelae frequently follow subarachnoid hemorrhage (SAH) and include deficits across multiple domains of executive function. This factor affects overall functional outcomes negatively, especially in younger patients. Several clinical correlates predict development and severity of cognitive dysfunction after SAH. Hypothetical mechanisms of cognitive dysfunction in the absence of radiographic lesion include cerebral hypoperfusion and blood breakdown products, resulting in perturbed interneuronal communication and network synchrony, excitotoxicity, and altered microRNA expression.

METHODS

The PubMed database was searched for articles discussing cognitive outcomes in patients with unruptured and ruptured intracranial aneurysmal disease, sequelae of treatment, and modalities for neuropsychologic testing.

RESULTS

Treatment of unruptured intracranial aneurysms, although capable of preventing SAH, comes with its own set of complications and may also affect cognitive function. Neuropsychological tests such as the Montreal Cognitive Assessment, Mini-Mental Status Examination, and others have proved useful in evaluating cognitive decline. Studies using functional neurologic imaging modalities have identified regions with altered activation patterns during various cognitive tasks. The sum of research efforts in this field has provided useful insights and an initial understanding of cognitive dysfunction after aneurysm treatment and SAH that should prove useful in guiding and rendering future investigations more fruitful.

CONCLUSIONS

Development of finer and more sensitive neuropsychological tests in evaluating the different domains of cognitive function after aneurysm treatment and SAH in general will be useful in accurately determining outcomes after ictus and comparing efficacy of different therapeutic strategies.

Sustained attention in psychosis: Neuroimaging findings

To provide a systematic review of scientific literature on functional magnetic resonance imaging (fMRI) studies on sustained attention in psychosis. We searched PubMed to identify fMRI studies pertaining sustained attention in both affective and non-affective psychosis. Only studies conducted on adult patients using a sustained attention task during fMRI scanning were included in the final review. The search was conducted on September 10^th, 2013. 15 fMRI studies met our inclusion criteria: 12 studies were focused on Schizophrenia and 3 on Bipolar Disorder Type I (BDI). Only half of the Schizophrenia studies and two of the BDI studies reported behavioral abnormalities, but all of them evidenced significant functional differences in brain regions related to the sustained attention system. Altered functioning of the insula was found in both Schizophrenia and BDI, and therefore proposed as a candidate trait marker for psychosis in general. On the other hand, other brain regions were differently impaired in affective and non-affective psychosis: alterations of cingulate cortex and thalamus seemed to be more common in Schizophrenia and amygdala dysfunctions in BDI. Neural correlates of sustained attention seem to be of great interest in the study of psychosis, highlighting differences and similarities between Schizophrenia and BDI.

Attention effects on auditory scene analysis: insights from event-related brain potentials

Sounds emitted by different sources arrive at our ears as a mixture that must be disentangled before meaningful information can be retrieved. It is still a matter of debate whether this decomposition happens automatically or requires the listener's attention. These opposite positions partly stem from different methodological approaches to the problem. We propose an integrative approach that combines the logic of previous measurements targeting either auditory stream segregation (interpreting a mixture as coming from two separate sources) or integration (interpreting a mixture as originating from only one source). By means of combined behavioral and event-related potential (ERP) measures, our paradigm has the potential to measure stream segregation and integration at the same time, providing the opportunity to obtain positive evidence of either one. This reduces the reliance on zero findings (i.e., the occurrence of stream integration in a given condition can be demonstrated directly, rather than indirectly based on the absence of empirical evidence for stream segregation, and vice versa). With this two-way approach, we systematically manipulate attention devoted to the auditory stimuli (by varying their task relevance) and to their underlying structure (by delivering perceptual tasks that require segregated or integrated percepts). ERP results based on the mismatch negativity (MMN) show no evidence for a modulation of stream integration by attention, while stream segregation results were less clear due to overlapping attention-related components in the MMN latency range. We suggest future studies combining the proposed two-way approach with some improvements in the ERP measurement of sequential stream segregation.

Mismatch negativity is a stronger indicator of functional outcomes than neurocognition or theory of mind in patients with schizophrenia

OBJECTIVES

Mismatch negativity (MMN) is known to be associated with neurocognition, social cognition, and functional outcomes. The present study explored the relationships of MMN with neurocognition, theory of mind, and functional outcomes in patients with schizophrenia, first-degree relatives of patients with schizophrenia, and healthy controls.

METHODS

Twenty-five patients with schizophrenia, 21 first-degree relatives of patients with schizophrenia, and 29 healthy controls were recruited. We examined symptom severity, neurocognition, theory of mind, functional outcomes, and MMN.

RESULTS

MMN amplitudes decreased in order of patients with schizophrenia, then first-degree relatives, then healthy controls. MMN amplitude was significantly correlated with measures of neurocognition, theory of mind, and functional outcome measurements in patients with schizophrenia. However, the most powerful correlations were those between MMN in the frontal region and measures of functional outcomes. The power and frequency of the correlations were weaker in first-degree relatives and healthy controls than in patients with schizophrenia. Hierarchical regression analysis revealed that functional outcomes (relative to measures of neurocognition and theory of mind) constituted the most powerful predictor of MMN.

CONCLUSIONS

Our results suggest that MMN reflects functional outcomes more efficiently than do measures of neurocognition and theory of mind in patients with schizophrenia.

Impaired sustained attention in euthymic bipolar disorder patients and non-affected relatives: an fMRI study

OBJECTIVE

Behavioral deficits in sustained attention have been reported during both acute and euthymic phases of type I bipolar disorder (BD-I) and also in non-affected relatives of bipolar disorder (BD) patients. In particular, selective failure in target recognition was proposed as a potential trait marker for BD, but there are few studies exploring the neural correlates. The aim of the present study was to analyze the behavioral and functional magnetic resonance imaging (fMRI) response of euthymic BD-I patients and non-affected relatives during a sustained attention task.

METHODS

Twenty-four euthymic BD-I patients, 22 non-affected first-degree relatives of BD-I subjects, and 24 matched controls underwent a continuous performance test (CPT) with two levels of difficulty during event-related fMRI scanning.

RESULTS

Both patients and relatives showed a lower accuracy in target detection when compared to controls. The fMRI data analysis revealed between-group differences in several brain regions involved in sustained attention. During error in target recognition, both patients and relatives showed a larger activation in the bilateral insula and the posterior part of the middle cingulate cortex. By contrast, during correct target response, only patients failed to activate the right insula, whereas relatives showed an increased activation of the left insula and bilateral inferior parietal lobule - limited to the higher attention load - and an augmented deactivation of the posterior cingulate/retrosplenial cortex.

CONCLUSIONS

A selective impairment in target recognition during a CPT was behaviorally and functionally detectable in both euthymic BD-I patients and non-affected first-degree relatives, suggesting that specific sustained attention deficits may be a potential trait marker for BD-I.

Altered brain response without behavioral attention deficits in healthy siblings of schizophrenic patients: an event-related fMRI study

Attention deficits are common in schizophrenics and sometimes reported in their healthy relatives. The aim of this study was to analyse the behavioural performance and the brain activation of healthy siblings of schizophrenic patients during a sustained-attention task. Eleven healthy siblings of schizophrenic patients and eleven matched controls performed a Continuous Performance Test (CPT), during 1.5 T fMRI. The stimuli were presented at three difficulty-levels, using different degrees of degradation (0, 25 and 40%). There were no significant differences in CPT performance (mean reaction time and percentage of errors) between the two groups. Performance worsened with increasing degradation in both groups. Differences were found when comparing the BOLD signal change in the medial frontal gyrus/dorsal anterior cingulate, right precentral gyrus, bilateral posterior cingulate and bilateral insula. The most evident between group differences were observed in the left insula/inferior frontal gyrus: siblings showed a larger activation during wrong responses and a reduced activation during correct responses in the degraded runs. In conclusion, healthy siblings of schizophrenic patients showed differences in brain function in several brain regions previously reported in schizophrenic subjects, in the absence of behavioral attention deficits. The differences were greater in the two more difficult levels of attention demand and might be expressions of altered and/or compensatory mechanisms in subjects at increased risk for schizophrenia.

Measurement of development of cognitive and attention functions in children using continuous performance test

AIM

The development of attention function in children is still not sufficiently clear. Although it is difficult to objectively assess attention function, continuous performance tests (CPT) can be used to objectively assess cognitive function along with attention. The development of cognitive and attention functions was examined in children using a CPT.

METHODS

A total of 541 healthy girls aged 5-12 years participated. Ten parameters were calculated: numbers of cancellations for either target stimuli (T-cancel) or non-target stimuli (N-cancel), numbers of omission errors (Omission) and commission errors (Commission), hit rate (Hit), false alarm rate (False), mean reaction time for correct response (RT), coefficient of variance for mean reaction time (CVRT), sensitivity index (d'), and lnbeta.

RESULTS

The parameters were divided into three types based on pattern of change. T-cancel, False, and Commission, which are related to inhibition of response, N-cancel, Hit, and Omission, which are related to inattention to stimuli, and CVRT, which is related to stability of processing time, exhibited significant change until 5 or 6 years of age. d', which is related to ability to discriminate between target or non-target, exhibited significant change until 8 years of age. RT, which is related to processing time, exhibited significant change until 11 years of age. lnbeta exhibited no significant differences among age groups.

CONCLUSIONS

These findings indicate that inhibition function, inattention to stimuli, and stability of processing time develop first. Discrimination ability subsequently increases based on these developments, and finally processing time is reduced.

Tone duration mismatch negativity deficits predict impairment of executive function in schizophrenia

Impairment in mismatch negativity (MMN) potentials is a robust finding in schizophrenia. There are few studies which examined the correlation between MMN deficits and neuropsychological performances. The purpose of this study was to investigate the relationship between deficits of tone duration MMN and various neuropsychological measures in schizophrenic patients (n=23). The results demonstrated a significant correlation between low MMN amplitude and poor performances of executive function in Wisconsin Card Sorting Test, Stroop Test and Trail Making Test. Our finding suggests MMN deficits in schizophrenia predict deficits of executive function and might reflect ongoing functional abnormality of fronto-temporal interaction.

Altered auditory processing in acutely psychotic never-medicated first-episode patients

Individuals with psychosis fail to differentiate external impulses and suffer from distortions of reality testing. Schizophrenia group illnesses are also associated with deficits in working memory and perception. We examined the manifestations of a very early phase of psychotic illness to automatic auditory deviance detection to clarify the basic mechanisms underlying misinterpretations of perception.

METHODS

Twenty-five never-medicated patients admitted for hospital evaluation of acute psychosis were studied. Fifty-eight EEG channels were recorded during an auditory oddball paradigm. Event-related potentials (ERPs) time-locked to non-attended deviant auditory stimuli were studied in patients and compared with healthy controls. Auditory processing was examined both at the level of the measured biosignals (standard and deviant responses) and with subtraction waveforms. Topographical differences were characterized using global field power (GFP) and minimum norm estimates.

RESULTS

The maximum GFP amplitudes and mean amplitudes of the 58 channels within the time windows corresponding to the previously known 'N2b', 'P3a' and 'P3b' components were clearly reduced in patients when compared to healthy controls. However, the groups did not differ during attention-independent automatic processing corresponding to the 'N1' and 'MMN' components, or with respect to the peak latencies of the GFP maxima.

CONCLUSIONS

Impairment of the processing of a deviance in simple auditory input in acutely ill drug-naive first-episode psychotic patients only appears in attention-dependent processing after about 250 ms. The alterations in auditory processing differed between stimulus types, suggesting at least two mechanisms underlying the auditory discrimination impairments in acute psychosis. After 250 ms there was a linear and gradually increasing difference in magnitude between the groups in their responses to deviant stimuli, probably related to arousal. In addition, however, there was a striking difference between the groups in the processing of standard stimuli. The early processing was similar in patients and controls, but the striking difference appeared in later processing. The sensory memory deficits associated with psychosis may be explained by an abnormality in sensory model formation rather than by impaired deviant detection.