Neuropsychological dysfunction in chronic fatigue syndrome and the relation between objective and subjective findings

Abstract:

OBJECTIVE: This study aimed to explore the relationship between self-reported cognitive difficulties, objective neuropsychological test performances, and subjective health complaints in chronic fatigue syndrome (CFS) and to examine the degree of impaired cognitive functions.

METHOD: A total of 236 consecutively recruited outpatients, 18-62 years of age, completed the tests. Self-administered questionnaires were used for assessing fatigue, pain, depression, anxiety and subjective cognitive complaints (Everyday Memory Questionnaire [EMQ]). Also, neuropsychological tests, that is, Stroop I-IV, California Verbal Learning Test-Second Edition (CVLT-II) learning and delay, Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) Letter Number (L-N) Sequencing, and the Paced Auditory Serial Addition Task were performed to examine whether these objective measures correlated with subjective complaints and were compared with normative data.

RESULTS: There was a trend of association (p < .05) between the unadjusted EMQ with Stroop IV (inhibition and shifting attention), the CVLT-II learning and delay (verbal learning and memory), and the WAIS-III L-N Sequencing (working memory), but none were statistically significant at the .001 level. The EMQ was positively associated with fatigue, pain, and depression (p < .001). The PASAT (working memory) was negatively associated with pain (p < .001). Between 21% and 38% of the patients performed below the 1.5-SD cutoff for clinically significant impairment on the Stroop tests.

CONCLUSION: The self-reported cognitive performance was not strongly associated with the objective cognitive performances on any domains in patients with CFS. Patients with higher fatigue, pain, and depression levels reported greater subjective cognitive difficulties, as well as higher pain related to lower objective working memory function. The CFS patients had problems mainly in the domains of psychomotor speed and attention measured by the objective neuropsychological tests. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

TRIAL REGISTRATION: ClinicalTrials.gov NCT00920777.

Source: Rasouli O, Gotaas ME, Stensdotter AK, Skovlund E, Landrø NI, Dåstøl P, Fors EA. Neuropsychological dysfunction in chronic fatigue syndrome and the relation between objective and subjective findings. Neuropsychology. 2019 Jun 6. doi: 10.1037/neu0000550. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31169386

Decreased basal ganglia activation in subjects with chronic fatigue syndrome: association with symptoms of fatigue

Abstract:

Reduced basal ganglia function has been associated with fatigue in neurologic disorders, as well as in patients exposed to chronic immune stimulation. Patients with chronic fatigue syndrome (CFS) have been shown to exhibit symptoms suggestive of decreased basal ganglia function including psychomotor slowing, which in turn was correlated with fatigue. In addition, CFS patients have been found to exhibit increased markers of immune activation.

In order to directly test the hypothesis of decreased basal ganglia function in CFS, we used functional magnetic resonance imaging to examine neural activation in the basal ganglia to a reward-processing (monetary gambling) task in a community sample of 59 male and female subjects, including 18 patients diagnosed with CFS according to 1994 CDC criteria and 41 non-fatigued healthy controls. For each subject, the average effect of winning vs. losing during the gambling task in regions of interest (ROI) corresponding to the caudate nucleus, putamen, and globus pallidus was extracted for group comparisons and correlational analyses.

Compared to non-fatigued controls, patients with CFS exhibited significantly decreased activation in the right caudate (p = 0.01) and right globus pallidus (p = 0.02). Decreased activation in the right globus pallidus was significantly correlated with increased mental fatigue (r2 = 0.49, p = 0.001), general fatigue (r2 = 0.34, p = 0.01) and reduced activity (r2 = 0.29, p = 0.02) as measured by the Multidimensional Fatigue Inventory. No such relationships were found in control subjects.

These data suggest that symptoms of fatigue in CFS subjects were associated with reduced responsivity of the basal ganglia, possibly involving the disruption of projections from the globus pallidus to thalamic and cortical networks.

 

Source: Miller AH, Jones JF, Drake DF, Tian H, Unger ER, Pagnoni G. Decreased basal ganglia activation in subjects with chronic fatigue syndrome: association with symptoms of fatigue. PLoS One. 2014 May 23;9(5):e98156. doi: 10.1371/journal.pone.0098156. ECollection 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4032274/ (Full article)

 

Cognitive impairment in fatigue and sleepiness associated conditions

Abstract:

Although relating to very different concepts, sleepiness and fatigue are often confounded. However, both fatigue-associated conditions such as the chronic fatigue syndrome (CFS) and sleepiness-associated conditions such as the sleep apnea-hypopnea syndrome (SAHS) are associated with cognitive impairment with impaired attention, concentration and memory performances.

Fifteen pure CFS patients, without primary sleep disorders or clinically relevant sleepiness, were compared to 15 untreated SAHS patients, without clinically relevant fatigue, and to 16 healthy controls of similar age. The auditory verbal learning test (AVLT), digit span, digit symbol and finger tapping test (FTT) were used as cognitive and behavioural measures. In addition we assessed daytime EEG spectral power and P300 evoked potentials.

With exception for the digit span, all tests showed lower performances in patient groups. Recall on the AVLT did not differ between the two patient groups, but the digit and symbol spans showed more severe impairment in SAHS patients. Psychomotor performance on the FTT presented with slower hit rates in SAHS than in CFS. EEG theta power was highest in CFS patients. P300 latencies and amplitudes did not differ between groups.

Fatigue- and sleepiness-associated conditions can both present with significant and objective impairment of cognitive functioning and behavioural motor performance. In our sample cognitive impairment and psychomotor performance were worse when associated to sleepiness in SAHS than with fatigue in CFS.

Copyright © 2010 Elsevier Ltd. All rights reserved.

 

Source: Neu D, Kajosch H, Peigneux P, Verbanck P, Linkowski P, Le Bon O. Cognitive impairment in fatigue and sleepiness associated conditions. Psychiatry Res. 2011 Aug 30;189(1):128-34. doi: 10.1016/j.psychres.2010.12.005. Epub 2010 Dec 31. https://www.ncbi.nlm.nih.gov/pubmed/21196050

 

Cognitive functioning in patients with chronic fatigue syndrome

Abstract:

A comprehensive battery of neuropsychological tests was administered to 35 outpatients suffering from Chronic Fatigue Syndrome (CFS). They were compared to 33 normal controls matched for age, gender, intelligence, and education.

The patients displayed psychomotor slowing and impaired attention. The learning rate of verbal and visual material for patients with CFS was slower, and delayed recall of verbal and visual information was impaired. Because there was a high variability in cognitive impairment within the CFS group, it would be inappropriate to generalize results to the entire CFS population. Two neuropsychological variables indicating aspects of psychomotor performance and verbal memory were found to discriminate best between patients and controls.

 

Source: Michiels V, Cluydts R, Fischler B, Hoffmann G, Le Bon O, De Meirleir K. Cognitive functioning in patients with chronic fatigue syndrome. J Clin Exp Neuropsychol. 1996 Oct;18(5):666-77. http://www.ncbi.nlm.nih.gov/pubmed/8941852

 

The existence of a fatigue syndrome after glandular fever

Abstract:

This prospective cohort study was designed to test whether a distinct fatigue syndrome existed after the onset of glandular fever.

Two hundred and fifty primary care patients, with either glandular fever or an ordinary upper respiratory tract infection (URTI) were interviewed three times in the 6 months after the clinical onset of their infection. At each interview a standardized psychiatric interview was given and physical symptoms were assessed. There were 108 subjects with and Epstein-Barr virus (EBV) infection; 83 subjects had glandular fever not caused by EBV and 54 subjects had an ordinary URTI. Five subjects were excluded because they had no evidence of an infection.

Principal components analyses of symptoms supported the existence of a fatigue syndrome, particularly in the two glandular fever groups. The addition of symptoms not elicited by the standard interviews gave the full syndrome. This included physical and mental fatigue, excessive sleep, psychomotor retardation, poor concentration, anhedonia, irritability, social withdrawal, emotional lability, and transient sore throat and neck gland swelling with pain. A fatigue syndrome probably exists after glandular fever.

 

Source: White PD, Thomas JM, Amess J, Grover SA, Kangro HO, Clare AW. The existence of a fatigue syndrome after glandular fever. Psychol Med. 1995 Sep;25(5):907-16. http://www.ncbi.nlm.nih.gov/pubmed/8588009

 

Quality of attention in chronic fatigue syndrome: subjective reports of everyday attention and cognitive difficulty, and performance on tasks of focused attention

Abstract:

Patients with chronic fatigue syndrome (also known as post-viral fatigue syndrome or myalgic encephalomyelitis) commonly report cognitive difficulties concerning attention, concentration and memory. In this study, patients were compared with matched controls on two questionnaires which assess subjective difficulties with attention and general cognitive functioning, and on two tasks requiring focused attention.

Patients reported significantly greater difficulty with attention on the Everyday Attention Questionnaire and more cognitive symptoms on the Profile of Fatigue-Related Symptoms. The objective tests did not clearly indicate a deficit in patients’ focused attention; patients tended to perform less well on the Embedded Figures Test and the Stroop Colour-Word Interference Test, but these differences were not significant.

There was, however, evidence of psychomotor retardation, with patients having longer response times for word reading and colour naming in the Stroop test. Difficulties in interpreting findings for both subjective and objective cognitive measures are discussed.

 

Source: Ray C, Phillips L, Weir WR. Quality of attention in chronic fatigue syndrome: subjective reports of everyday attention and cognitive difficulty, and performance on tasks of focused attention. Br J Clin Psychol. 1993 Sep;32 ( Pt 3):357-64. http://www.ncbi.nlm.nih.gov/pubmed/8251968