Paul Eling

Work stress and attentional difficulties: An initial study on burnout and cognitive failures

Professional burnout is a stress-related disorder, having mental exhaustion due to work stress as its most important characteristic. Burned out individuals also often complain about attentional problems. However, it is currently not clear whether such complaints are based on true cognitive deficits or whether they merely reflect the way burned out individuals rate their own cognitive performance. To confirm the cognitive complaints we used a cognitive failure questionnaire (CFQ) to assess the level of self-reported attentional difficulties in daily life. We also measured performance on tasks of sustained attention and response inhibition (the SART and the Bourdon-Wiersma Test). We compared three groups: (1) a group of ‘burned out’ individuals (n=13) who stopped working due to their symptoms and sought professional treatment; (2) teachers at a vocational training institute (n=16) who reported high levels of burnout symptoms but continued to work; and (3) teachers from the same institute (n=14) who reported no burnout symptoms. The level of burnout symptoms was found to be significantly related to the number of cognitive failures in daily life, and to inhibition errors and performance variability in the attentional tasks. To our knowledge, explicit tests of objective cognitive deficits in burned out individuals have not been conducted before. Consequently, this is the first study to indicate that burnout is associated with difficulties in voluntary control over attention and that the level of such difficulties varies with the severity of burnout symptoms.

Time Pressure Management as a Compensatory Strategy Training after Closed Head Injury

Following severe closed head injury, deficits in speed of information processing are common. As a result, many head-injured patients experience a feeling of “information overload” in daily tasks that once were relatively easy. Many remedial programmes have been designed that treat different aspects of attention (often including mental speed requirements) by repetitive exercises. In the present study, a different approach to slow information processing has been taken, namely Time Pressure Management (TPM). TPM consists of a set of alternative cognitive strategies that allow head-injured patients in real-life tasks to compensate for their mental slowness. In a randomised pre-training vs. post-training vs. follow-up group study, the effectiveness of TPM training was compared with concentration training in which verbal instruction was the key element. The results indicate that specific TPM strategies are learned by the experimental subjects but that both treatments improve task performance significantly for an information intake task. TPM, however, produces greater gains than concentration training and also appears to generalise to other measures of speed and memory function.

Response Shifting and Inhibition, but Not Working Memory, Are Impaired After Long-Term Heavy Alcohol Consumption

Chronic alcohol abuse leads to cognitive deficits. The authors investigated whether a systematic increase of interference in a 2-back working memory paradigm would lead to cognitive deficits in alcoholic participants and compared their performance in such a task with that in an alternate-response task. Twenty-four nonamnesic and nondemented alcohol abuse (AA) patients and 12 patients with Korsakoffs syndrome (KS) were compared with a control group. AA patients were impaired in the alternate-response task but not in working memory interference resolution. KS patients performed worse than the AA patients and the controls in both tasks. The neurotoxic side effects of alcohol therefore lead to a specific deficit in alternating between response rules but not in working memory, independently of whether the working memory task involves interference resolution or not.

The association between California Verbal Learning Test performance and fibre impairment in multiple sclerosis: evidence from diffusion tensor imaging

The California Verbal Learning Test (CVLT) is recognized as a standard clinical tool for assessing episodic memory difficulties in multiple sclerosis (MS), but its neural correlates have not yet been examined in detail in this patient population. We combined neuropsychological examination and diffusion tensor imaging (DTI) analysis in a group of MS patients (N = 50) and demographically matched healthy participants (N = 20). We investigated the degree of impairment of the uncinate fascicle (UF), the superior longitudinal fascicle (SLF), the fornix (FX) and the cingulum (CG). The patients were impaired on all CVLT parameters and the DTI parameters correlated moderately with disease-related variables. Regression analyses in the complete study sample showed that CVLT learning scores correlated with impairment of the right UF. This association reached marginal significance in the patient sample. In contrast to other studies claiming retrieval deficits, our results suggest that encoding and consolidation deficits may play a major role in verbal memory impairments in MS. The findings also provide evidence for an association between degree of myelination of prefrontal fibre pathways and encoding efficiency. Finally, DTI-derived measurements appear to reflect disease progression in MS. The results are discussed in light of functional MRI studies investigating compensatory brain activity during cognitive processing in MS.

Attentional set shifting in autism spectrum disorder: differentiating between the role of perseveration, learned irrelevance, and novelty processing.

Autism spectrum disorders (ASD) are associated with impaired attentional set shifting, which may reflect enhanced perseverative responding, enhanced learned irrelevance, and/or reduced novelty processing. We assessed the contribution of these potential error sources in ASD adults. A total of 17 ASD and 19 matched comparison individuals first solved a discrimination learning task. Thereafter, the participants faced three types of attentional shift, specifically designed to isolate the effect of the three possible error sources. ASD participants made more errors than comparison individuals in a shift implying a choice between a novel relevant stimulus attribute and a familiar attribute that was previously relevant but now irrelevant. However, they made fewer errors in a shift involving a choice between a novel irrelevant attribute and a familiar, previously irrelevant but now relevant attribute. The results in combination suggest that the performance difference, at least in the present shift task, is caused by reduced novelty processing in ASD participants.

How simple complex words can be: Morphological processing and word representations

In four lexical decision experiments we studied the effect of morphological complexity on word recognition. Some potentially relevant linguistic aspects of derived nouns were varied: the location of the affix (prefix vs. suffix); the genuineness of the affix (real vs. pseudo); the orthographic legality of pseudo-stems; semantic compositionality; the nature of the stem (free vs. bound); the origin of the complex word (Latinate vs. Germanic); the currency of the stem (current vs. moribund). Furthermore, in the first two experiments, we systematically varied the proportion of complex and simple words to see whether strategies influence morphological effects on recognition times. Consistent with Tafts notion of affix stripping, pseudoprefixed words show longer mean decision times and higher error rates than truly prefixed words. Further, the prefixed and nonprefixed (but not pseudoprefixed) words are processed equally rapidly, indicating that a decompositional process is efficient. No differences were found, however, for suffixed, pseudosuffixed, and nonsuffixed words. There was no effect of the proportion of simple and complex words. There are some indications that the etymological origin of words may affect recognition times, but no other linguistic aspects of derivations do so. The results of the four experiments are interpreted as supporting a left-to-right process for word recognition in which morphemes are extracted automatically. During this process information encoded by morphological structure becomes available for other processes.

Decreased hippocampal volume, indirectly measured, is associated with depressive symptoms and consolidation deficits in multiple sclerosis:

Background: The human hippocampus plays a role in episodic memory and depression. Recently, it has been shown, using manual tracings, that the hippocampus is smaller in volume in MS patients compared with healthy controls, and that, at least for depression, hippocampal atrophy correlates with symptom severity. Methods: Because manual tracing of the hippocampus is time consuming, we used a semi-automatic procedure for temporal horn volumetry in 72 multiple sclerosis (MS) patients and 16 control subjects as an indirect measure of hippocampal volume. We analysed memory performance with the California Verbal Learning Test (using separate indices for encoding, consolidation and retrieval) and depressive mood with the Beck’s Depression Inventory (distinguishing between psychic and somatic aspects). Results: MS patients had significantly larger temporal horn volumes and volume correlated with psychic symptoms of depressive mood. Temporal horn volume was also associated with consolidation, in particular in the most impaired group. Conclusions: Temporal horn volume can be measured relatively easily and appears to correlate with two major clinical problems in MS patients: memory performance and depressive mood. The link between temporal horn volume, consolidation and depression may be hippocampal atrophy, as suggested by their adjacent neuroanatomical localization, and by the similarity in functional loss following impairment of these two structures.

Efficacy of an executive function intervention programme in MS: a placebo-controlled and pseudo-randomized trial

We evaluated a rehabilitation programme for executive deficits in multiple sclerosis patients by comparing outcome scores of a cognitive intervention group (CIG; n = 11) with those of a placebo group (n = 14) and an untreated group (n = 15). Executive functioning and verbal learning improved significantly more in the CIG. The treatment effect on verbal learning was still present at 1-year follow-up. Baseline brain atrophy, quantified by the brain parenchymal fraction, was associated with treatment effects for one aspect of executive functioning. Consequently, cognitive intervention may be beneficial and baseline brain atrophy has some predictive value in determining treatment outcome for executive functioning.

The representation of inflammatory signals in the brain - a model for subjective fatigue in multiple sclerosis

In multiple sclerosis (MS) patients, fatigue is rated as one of the most common and disabling symptoms. However, the pathophysiology underlying this fatigue is not yet clear. Several lines of evidence suggest that immunological factors, such as elevated levels of pro-inflammatory cytokines, may contribute to subjective fatigue in MS patients. Pro-inflammatory cytokines represent primary mediators of immune-to-brain-communication, modulating changes in the neurophysiology of the central nervous system. Recently, we proposed a model arguing that fatigue in MS patients is a subjective feeling, which is related to inflammation. Moreover, it implies that fatigue can be measured behaviorally only by applying specific cognitive tasks related to alertness and vigilance. In the present review, we focus on the subjective feeling of MS-related fatigue. We examine the hypothesis that the subjective feeling of MS-related fatigue may be a variant of inflammation-induced sickness behavior, resulting from cytokine-mediated activity changes within brain areas involved in interoception and homeostasis including the insula, the anterior cingulate, and the hypothalamus. We first present studies demonstrating a relationship between pro-inflammatory cytokines and subjective fatigue in healthy individuals, in people with inflammatory disorders, and particularly in MS patients. Subsequently, we discuss studies analyzing the impact of anti-inflammatory treatment on fatigue. In the next part of this review, we present studies on the transmission and neural representation of inflammatory signals, with a special focus on possible neural concomitants of inflammation-induced fatigue. We also present two of our studies on the relationship between local gray and white matter atrophy and fatigue in MS patients. Finally, we discuss some implications of our findings and future perspectives.

The internal representation of arithmetical word problem sentences : frontal and posterior-injured patients compared

Patients with frontal and left posterior brain lesions have severe difficulties in arithmetical word problem solving. In the present study the origin of these difficulties is investigated from an information-processing perspective. Following this perspective the first stage in word problem solving consists of a translation of individual sentences to an internal representation. This translation process is examined in 30 frontal patients, 10 left posterior-injured patients, and 10 healthy controls with a recognition and a sentence-picture matching task. In addition, the relationship between sentence representation and arithmetical word problem solving is studied. The results suggest that error rates in the translation of different types of arithmetical word problem propositions differ substantially in our three groups. A relationship between translation skills and arithmetical word problem solving ability is also found.