Factors Associated With Fatigue in People With Spinal Cord Injury: A Systematic Review and Meta-analysis.

OBJECTIVE: To investigate the association between fatigue and clinical and demographic variables in people with spinal cord injury (SCI). DATA SOURCES: Five databases (MEDLINE, Physiotherapy Evidence Database, Cochrane, Google Scholar, Cumulative Index to Nursing and Allied Health) were searched up to November 2021. STUDY SELECTION: Observational studies that reported the association between fatigue and clinical and demographic variables in English or Spanish were eligible. Reviews, qualitative research studies, and nonoriginal articles were excluded. Twenty-three of the 782 identified studies met the inclusion criteria for the meta-analysis. DATA EXTRACTION: Two researchers independently extracted the data. The strength of the association between each factor and fatigue was determined by the effect size. When the results of the effect size were expressed with different statistics, the correlation coefficient was the preferred estimation. The risk of bias was assessed using the Appraisal Tool for Cross-Sectional Studies and the Newcastle-Ottawa Scale. DATA SUMMARY: A pooled analysis of the associations between fatigue and 17 factors was performed. A direct association was found between fatigue and 9 factors (sorted by effect size): anxiety (r=0.57; 95% CI, 0.29-0.75), stress (r=0.54; 95% confidence interval [CI], 0.26-0.74), depression (r=0.47; 95% CI, 0.44-0.50), pain (r=0.34; 95% CI, 0.16-0.50), analgesic medication (r=0.32; 95% CI, 0.28-0.36), assistive devices (r=0.23; 95% CI, 0.17-0.29), lesion level (r=0.15; 95% CI, 0.07-0.23), incomplete SCI (r=0.13; 95% CI, 0.05-0.22), and medication (r=0.12; 95% CI, 0.01-0.23). An inverse association was found with 3 factors (sorted by effect size): self-efficacy (r=-0.63; 95% CI, -0.81 to -0.35), participation (r=-0.32; 95% CI, -0.58 to -0.001), and physical activity (r=-0.17; 95% CI, -0.28 to -0.05). No association was found with age, sex, educational level, time since injury, and spasticity. CONCLUSIONS: Several factors were associated with fatigue in people with SCI, with those related to mental health showing the strongest associations. These results should be interpreted with caution because of the high heterogeneity observed in some factors.

Hand Motor Fatigability Induced by a Simple Isometric Task in Spinal Cord Injury.

This study aimed: (1) to evaluate the hand motor fatigability in people with spinal cord injury (SCI) and compare it with measurements obtained form an able-bodied population; (2) to compare the hand motor fatigability in people with tetraplegia and in people with paraplegia; and (3) to analyse if motor fatigability is different in people with SCI with and without clinical significant perceived fatigability. MATERIALS AND METHODS: 96 participants with SCI (40 cervical and 56 thoracolumbar) and 63 able-bodied controls performed a simple hand isometric task to assess motor fatigability. The Fatigue Severity Scale was used for perceived fatigability evaluation. RESULTS: The main results of this study can be summarized as follows: (1) the waning in muscle force (motor fatigability) during a fatiguing task is similar in controls and participants with SCI; (2) the motor fatigability is influenced by the maximal muscle force (measured at the beginning of the task); and (3) the perceived fatigability and the motor fatigability are largely independent in the individuals with SCI. CONCLUSION: Our findings suggest that the capability to maintain a prolonged effort is preserved in SCI, and this capacity depends on the residual maximal muscle force in people with SCI.

Effects of fatigue induced by repetitive movements and isometric tasks on reaction time.

PURPOSE: The understanding of fatigue of the human motor system is important in the fields of ergonomics, sport, rehabilitation and neurology. In order to understand the interactions between fatigue and reaction time, we evaluated the effects of two different fatiguing tasks on reaction time. METHODS: 83 healthy subjects were included in a case-control study with three arms where single and double choice reaction time tasks were performed before and after 2 min fatiguing task (an isometric task, a finger tapping task and at rest). RESULTS: After an isometric task, the right-fatigued hand was slower in the choice component of a double choice reaction time task (calculated as the individual difference between single and double choice reaction times); also, the subjects that felt more fatigued had slower choice reaction time respect to the baseline assessment. Moreover, in relationship to the performance decay after two minutes, finger tapping task produces more intense fatigability perception. CONCLUSIONS: We confirmed that two minutes of isometric or repetitive tasks are enough to produce fatigue. The fatigue perception is more intense for finger tapping tasks in relation to the performance decay. We therefore confirmed that the two fatiguing tasks produced two different kind of fatigue demonstrating that with a very simple protocol it is possible to test subjects or patients to quantify different form of fatigue.

Effects of transcranial direct current stimulation on temperature and pain perception.

Transcranial direct current stimulation modifies cortical excitability and in consequence some cerebral functions. In the present study we aimed to elucidate whether tDCS could affect temperature and pain perceptions in healthy subjects testing different stimulation parameters. A total of 20 healthy subjects were studied by means of quantitative sensory testing. Two different experiments were performed. First, we studied the effects of 15 minutes 2 mA anodal transcranial direct current stimulation applied over left M1 and parietal cortex in two separated sessions. Then, we tested the effects of 5 minutes tDCS over M1 by means of a sham controlled design to optimize the possibility to study minimal effects of tDCS using different polarities (cathodal and anodal) and intensities (1 and 2 mA). 2 mA anodal tDCS, when applied for both 15 and 5 minutes over the motor cortex, increased cold perception threshold. Conversely, motor cortex cathodal tDCS modulated cold perception threshold only when 1 mA intensity was used. M1-tDCS can modify the temperature perception; these effects are polarity and intensity dependent. As stimulation intensity seems critical to determine the effects, we suggest that for clinical application strong anodal tDCS (>1 mA) or weak cathodal tDCS (<2 mA) should be used for pain control.

Prevalence of Fatigue and Associated Factors in a Spinal Cord Injury Population: Data from an Internet-Based and Face-to-Face Surveys.

Fatigue has a profound impact on patients with spinal cord injury (SCI), but only limited treatments are available. The aim of this study was to determine the prevalence of fatigue in SCI and its association with clinical and demographic factors. We used an internet-based survey and a face-to-face interview to estimate the prevalence of fatigue in a SCI population. Fatigue was measured using the Fatigue Severity Scale (FSS). Clinically significant fatigue was defined as FSS scores greater than or equal to four. A total of 253 participants with SCI were included in the study. Clinically significant fatigue was present in one third of our sample. There was no relationship between fatigue and injury level or completeness. We found significant correlations between depression, pain, and level of injury. The relation of fatigue with completeness of injury and spasticity is less clear. Moreover, the online survey and the standard face-to-face interview showed similar results concerning fatigue evaluation. Several factors may contribute to fatigue, however. Future studies should be conducted to clarify which are the most relevant ones and, if possible, to determine which factors are modifiable.