Annotated Abstracts of Journal Articles
2014, 1st Quarter
Annotations by Nicholas Kontos, MD
March 2014
Also of interest:
ANNOTATION (Nicholas Kontos)
The Finding: The authors postulate and support the existence of “echothymia,” an affective version of what is referred to in various contexts as environmental dependency (utilization and imitation behaviors), echophenomena (echolalia, echopraxia), or stimulus bounded-ness.
Strengths and Weaknesses: The concept makes sense anatomically and clinically. There is inherent interest in seeing a genuinely new phenomenological concept introduced and neuroanatomically situated. The authors do take some liberties with their own ideas, especially when considering treatment. While the article appears in a subspecialty journal, it does presume knowledge of Lhermitte’s original work on environmental dependency, and so the anatomic mechanism of echothymia might not be clear to all readers. The quality of the writing is not very good, and sometimes leads to confusion and unnecessary repetition even within a short paper.
Relevance: Given its fundamentally different nature/etiology compared with other secondary and primary affective disturbances, the concept of echothymia is not just an interesting consideration, but one of potential practical importance.
Echothymia is stimulus-bound affective behavior, an echophenomenon in the domain of affect. Like echolalia and echopraxia, it is a concomitant of the environmental dependency associated with dysfunction of the frontal-striatal systems that mediate so-called frontal lobe functions. The authors introduce the definition and phenomenology of echothymia, overview its differential diagnosis and clinical significance, and suggest ways in which understanding echothymia may contribute to clinical management.
ANNOTATION (Nicholas Kontos)
The Finding: Among patients with fibromyalgia, “moderate” support is found for various differences in brain anatomy and connectivity among areas associated with pain processing.
Strengths and Weaknesses: The authors provide a nice basic review of the concept of central sensitization. The paper serves an admirable function in pausing to gather together and make collective sense of the findings to-date in this relatively booming topic area. The authors are predominantly from the field of rehabilitation, and this might contribute to a sometimes superficial discussion of the relevant neuroanatomy.
Relevance: Central sensitization is a major area of study within the field of somatic symptom disorders and functional somatic syndromes. While psychodynamic understandings and assumptions about “somatization” remain important, central sensitization connects neuroscience and the cognitive-behavioral model of problematic medically unexplained symptoms in intriguing and falsifiable ways.
Objectives: The aim of the present study was to systematically review the literature addressing pain-induced changes in the brain related to central sensitization in patients with fibromyalgia (FM) using specific functional (rs-fMRI and fMRI) and structural (voxel-based morphometry-VBM) brain MRI techniques.
Methods: PubMed and Web of Science were searched for relevant literature using different key word combinations related to FM, brain MRI, and central sensitization. Full-text reports fulfilling the inclusion criteria were assessed on risk of bias and reviewed by two independent reviewers.
Results: From the 61 articles that were identified, 22 met the inclusion criteria and achieved sufficient methodological quality. Overall, eight articles examined structural brain (VBM) changes in patients with FM, showing moderate evidence that central sensitization is correlated with gray matter volume decrease in specific brain regions (mainly anterior cingulate cortex and prefrontal cortex). However, global gray matter volume remains unchanged. A total of 13 articles evaluated brain activity (fMRI) in response to a nociceptive stimulus. Findings suggest a higher but similar pattern of activation of the pain matrix in FM patients compared to controls. There is also evidence of decreased functional connectivity in the descending pain-modulating system in FM patients. Overall, two articles examined intrinsic brain connectivity in FM patients with rs-fMRI. In conclusion, there is moderate evidence for a significant imbalance of the connectivity within the pain network during rest in patients with FM.
Conclusions: The included studies showed a moderate evidence for region-specific changes in gray matter volume, a decreased functional connectivity in the descending pain-modulating system, and an increased activity in the pain matrix related to central sensitization. More research is needed to evaluate the cause-effect relationship.
ANNOTATION (Nicholas Kontos)
The Finding:
Cognitive deficits at six months post-stroke (without regard for localization) were startlingly common in a relatively young cohort. Further, a screening instrument employed at the time of discharge was of limited use in predicting this.
Strengths and Weaknesses: Strict definitions for cognitive impairment were used; along with the relatively young sample, this makes the study’s findings fairly striking. Baseline cognitive status of the subjects is unknown, however; and while presumed to be buoyed by age, relative youth plus stroke suggests unfavourable CNS vasculopathy burden, thus mitigating assumptions about baseline cognition.
Relevance: This study highlights the need for serial cognitive screening in acute, subacute, and remote stroke victims. The importance of formal neuropsychological testing when subjective functioning and “bedside” screening are incongruent is suggested.
Background: We aim to facilitate recognition of the cognitive burden of stroke by describing the parallels between cognitive deficits and the National Institutes of Health Stroke Scale (NIHSS), a widely used measure of stroke severity.
Methods: A consecutive cohort of 223 working-age patients with an acute first-ever ischaemic stroke was assessed neuropsychologically within the first weeks after stroke and at a 6-months follow-up visit and compared with 50 healthy demographic controls. The NIHSS was administered at the time of hospital admittance and upon discharge from the acute care unit. The associations between total NIHSS scores and domain-specific cognitive deficits were analysed correlatively and with a binary logistic regression.
Results: Of the NIHSS measurements (admittance median=3, range 0-24; discharge median=1, range 0-13), the total score at the time of discharge had systematically stronger correlations with cognitive impairment. Adjusted for demographics, the NIHSS discharge score stably predicted every cognitive deficit with ORs ranging from 1.4 (95% CI 1.2 to 1.6) for episodic memory to 1.9 (95% CI 1.5 to 2.3) for motor skills. The specificities of the models ranged from 89.5-97.7%, but the sensitivities were as low as 11.6-47.9%. Cognitive deficits were found in 41% of patients with intact NIHSS scores and in all patients with NIHSS scores ≥4, a finding that could not be accounted for by confounding factors.
Conclusions: Cognitive deficits were common even in patients with the lowest NIHSS scores. Thus, low NIHSS scores are not effective indicators of good cognitive outcomes after stroke.