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Rehabilitation Psychology 2006, Vol. 51, No. 2, 140 –149

Copyright 2006 by the American Psychological Association 0090-5550/06/$12.00 DOI: 10.1037/0090-5550.51.2.140

Fatigue Following Traumatic Brain Injury: Frequency, Characteristics, and Associated Factors Marie-Christine Ouellet and Charles M. Morin Universite´ Laval Objectives: To document the frequency, characteristics, and factors associated with fatigue following traumatic brain injury (TBI). Design: Survey methodology and multivariate statistical design. Setting: Rehabilitation center and community. Participants: 452 participants aged 16 years and over with minor to severe TBI who answered a questionnaire measuring diverse aspects of fatigue as well as different dimensions of psychological distress, pain, and sleep quality. Measures: Proportion of participants reporting being significantly fatigued. Validated measures of fatigue, sleep quality, and psychological distress. Results of a logistic regression analysis. Results: Significant fatigue was reported by 68.5% of participants. Mental fatigue was the most prominent type of fatigue, followed by physical fatigue. Fatigue was present even several years following the accident and had many perceived impacts on day-to-day function. Factors associated with fatigue were a shorter time since injury; being on long-term disability leave; and higher levels of sleep problems, cognitive disturbances, and anxiety. Conclusion: Fatigue is a prevalent problem after TBI that requires more clinical and scientific attention because it probably has important repercussions on the quality of rehabilitation. Keywords: fatigue, traumatic brain inury

related to the severity of neurological abnormalities (Ingles et al., 1999; van der Werf et al., 1998), but factors such as depression and sleep disturbances have been found to contribute to fatigue (Strober & Arnett, 2005). It remains unclear how TBI-related fatigue resembles or differs from fatigue in other neurological conditions. Studies conducted mainly among persons with minor TBI and evaluating a variety of residual symptoms reveal that between 20% and 70% of individuals endorse fatigue as a symptom following their accident (Dikmen, McLean, & Temkin, 1986; Keshavan, Channabasavanna, & Narayana Reddy, 1981; Levin et al., 1987; Middleboe, Andersen, Birket-Smith, & Friis, 1992; Minderhoud, Boelens, Huizenga, & Saan, 1980; Oddy, Coughlan, Tyerman, & Jenkins, 1985; van Zomeren & van den Burg, 1985; Walker, Cardenas, Guthrie, McLean, & Brooke, 1991; Wrightson & Gronwall, 1981). Although very limited longitudinal data is available, there is some evidence to suggest that rates of fatigue decrease somewhat over time in persons with minor TBI, with 27– 69% reporting fatigue after 1 month, 22–37% after 3 months, and 19 –23% after 6 months (Dikmen et al., 1986; Levin et al., 1987; Minderhoud et al., 1980). Studies in more severe cases of TBI suggest that 30 – 63% of individuals report fatigue even up to several years post-TBI (Clinchot, Bogner, Mysiw, Fugate, & Corrigan, 1998; Keshavan et al., 1981; van Zomeren & van den Burg, 1985; Walker et al., 1991). Despite the apparently very high prevalence of fatigue following TBI, only two studies have focused specifically on this subject (LaChapelle & Finlayson, 1998; Walker et al., 1991). Walker et al. (1991) attempted to objectify fatigue in individuals with TBI by using measures of quadriceps strength and endurance. Although the participants reported more fatigue when evaluated with subjective measures, they did not significantly differ from healthy control participants on muscular strength or endurance. It is inter-

Among the persisting symptoms of traumatic brain injury (TBI), fatigue has received very little scientific attention despite the fact that it is reported by large numbers of individuals with TBI and seems to persist months and even years after the injury. The multidimensional and subjective nature of fatigue probably accounts for the fact that researchers have neglected this widespread and debilitating symptom of TBI. Indeed, even if fatigue is a universal phenomenon, there is a lack of consensus on its definition, no real answers pertaining to its physiological or neurological etiology (St-Clair Gibson et al., 2003), and few reliable subjective or objective measures to assess it (LaChapelle & Finlayson, 1998). Despite the elusiveness of fatigue, it appears essential to address more closely this issue in TBI since fatigue probably exacerbates other symptoms related to brain injury such as pain, cognitive deficits, or emotional difficulties. Thus, fatigue may compromise the speed or quality of the rehabilitation process and most certainly hinders individuals’ capacities to resume certain occupational, leisure, or social activities. Fatigue is a common consequence of various neurological disorders including stroke, multiple sclerosis, poliomyelitis, and chronic fatigue syndrome (Chaudhuri & Behan, 2004). Research has shown that fatigue can cause significant distress and have detrimental impacts on daily functioning and overall well-being (Ingles, Eskes, & Phillips, 1999; Strober & Arnett, 2005). In multiple sclerosis and stroke, fatigue has not been found to be

Marie-Christine Ouellet and Charles M. Morin, E´cole de Psychologie, Universite´ Laval. Correspondence concerning this article should be addressed to MarieChristine Ouellet, Ph.D., E´cole de Psychologie, Universite´ Laval, Pavillon Fe´lix-Antoine-Savard, Que´bec QC GK1 7P4, Canada. E-mail: [email protected] 140

FATIGUE FOLLOWING TBI

esting, however, that the participants with brain injury were found to have significantly higher depression and anxiety scores relative to healthy controls. Individuals reporting fatigue were also found to be more depressed and anxious than their nonfatigued counterparts. In another attempt to objectively measure fatigue in a group of persons with TBI, LaChapelle and Finlayson (1998) used a thumbpressing task and correlated it with three subjective measures of fatigue. No significant differences were found between participants having suffered TBI and control participants on the thumb-pressing task although there was a trend toward more fatigue in the TBI group. Nonetheless, the TBI group was found to be more fatigued when subjective measures such as the Fatigue Severity Scale were used. They also experienced fatigue more often per month than healthy participants, and 49% reported fatigue as being one of their worst symptoms. A negative correlation was found between the time since injury and the severity of fatigue, suggesting an improvement of fatigue over time. Together, the findings of these two studies suggest that objective measures such as physical strength or endurance probably fail to capture the subjective and multidimensional nature (e.g., mental vs. physical) of fatigue following TBI. Knowledge is still lacking regarding the appearance, time course, nature, and severity of fatigue. The daily variations and behavioral correlates (i.e., resttaking and napping habits) of fatigue have yet to be described, together with its impact on different areas of the lives of individuals with TBI such as their mood, cognitive functioning, and global quality of life. Finally, no study has examined potential risk factors for fatigue following TBI. A variety of factors such as age, the severity of injury, the presence of pain, depression, anxiety, cognitive disturbances, or sleep problems may be associated with the development or perpetuation of fatigue in persons with brain injury. A better understanding of the determinants of fatigue in TBI could stimulate the development of more systematic approaches to fatigue management. The objectives of this study were (1) to document the proportion of individuals suffering from significant fatigue in a heterogeneous

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sample of individuals with TBI in the postacute phase, (2) to describe different characteristics of post-TBI fatigue (e.g., nature, severity, appearance, duration, impact), and (3) to study the factors associated with the presence of fatigue in this population.

Method Participants The sample was composed of French-speaking individuals residing in the province of Quebec who sustained a TBI. Potential participants received by mail a questionnaire booklet entitled “The Quality of Sleep and Level of Fatigue Following a Traumatic Brain Injury” from which the data of this study were derived. The same data set was used in another study to explore the frequency, characteristics, and factors associated with insomnia in this population (Ouellet, Beaulieu-Bonneau, & Morin, in press). Approximately 1500 questionnaires were distributed through the archives of Que´bec City’s largest rehabilitation center and via mailing lists of TBI associations or support groups in 11 regions throughout the province. Among the participants who received the questionnaire by mail, 460 completed and returned the study material. Liberal inclusion criteria were used in order to obtain a global portrait of the TBI population. To participate in the study, potential participants (1) were aged 16 years or over and (2) had sustained either minor, mild, moderate, or severe TBI, regardless of the time since injury. Since we did not have access to patients’ medical files because of the anonymous nature of the study, we had to rely on the patients’ self-reports of the severity of their injuries as presented to them by their health professionals. TBI severity was determined by health professionals implicated in each patient’s case (e.g., neurologist, neuropsychologist) according to the following criteria used routinely in Que´bec rehabilitation centers (Gervais & Dube´, 1999): duration of altered consciousness, earliest Glasgow Coma Scale score, presence or absence of objective lesions upon neurological examination, duration of posttraumatic amnesia, and degree of incapacitation (see Table 1). To obtain a measure of the reliability of patients’ self-reports of severity of their injuries, we were able to match the reported TBI severity with that of medical charts for 13% of the global sample (individuals who voluntarily gave us their names). Of this subsample, only 5 individuals out of 61 did not give the exact TBI severity, suggesting that TBI was adequately reported in this study.

Table 1 Categorization of TBI Severity Used Routinely in Que´bec Rehabilitation Facilities as Described by Gervais and Dube´ (1999) Characteristics

Minor

Duration of loss of consciousness

0 to 10 minutes

Glasgow Coma Scale score in the emergency room or 30 minutes after the accident Objective identification of cerebral lesions

15

Duration of posttraumatic amnesia Sequelae or incapacities

0 to 10 minutes (maximum)

Negative scan, Negative MRI

None to mild and temporary

Mild

Moderate

Severe

A few minutes, up to 30 minutes 13 to 15

Generally between 30 minutes and 6 hours, not more than 24 hours 9 to 12

Generally more than 24 hours, must be more than 6 hours 8 or less

Negative scan, Negative or positive MRI Less than 24 hours

Scan is generally positive, Positive MRI

Positive scan, Positive MRI

Generally between 24 hours and 14 days

Several weeks

Mild to moderate

Mild to severe

Severe

Note. Adapted from E´tude exploratoire des besoins en services offerts a` la ciente`le troumatise´e cranio-ce´re´brale au Que´bec, by M. Gervais and S. Dube´, 1999, Quebec: Universite´ Laval, Institut de re´adaptation en de´ficience physique deq Ue´bec. Copyright 1999 by M. Gervais. Adapted with permission.

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Four questionnaires were excluded because they clearly had been completed by another person without the patient’s participation (as evaluated by a key question at the end of the questionnaire). Four questionnaires were excluded because the participants had not sustained TBI but some other form of trauma or neurological problem. The final sample thus consisted of 452 participants. The sample composition was 65% men, 35% women. The mean age was 40.22 years (SD ⫽ 13.07), and 40% were married or living with a partner. A total of 79.2% reported living in their own apartment or house, whereas the remainder were living with family members, friends, or in a rehabilitation center. The mean number of years of education was 11.5 (SD ⫽ 2.9). More than half (52.3%) of the entire sample reported being on long-term disability leave; 14.4% reported working or studying full time, whereas 17.4% were working or studying on a part-time basis. Of the entire sample, 16.7% were retired, and 23.3% were doing some form of volunteer work. The majority (59.9%) of the sample was composed of individuals who sustained severe TBI; 23.3% had sustained brain injury of moderate severity, 13.7% a mild TBI, and 3.1% a minor TBI. The average time elapsed since the accident was 7.85 years (SD ⫽ 7.53). Motor vehicle accidents were the cause of TBI in 73.6% of cases, whereas the rest involved other types of accidents (e.g., falls, assaults, work related injuries). The majority (87.2%) of participants were no longer in rehabilitation at the time of the study.

Procedure To obtain a sample as representative as possible, all potential participants were invited to complete the measures included in the mailing package. This package contained an information sheet, a questionnaire for the person with TBI, as well as a questionnaire for a significant other. Participants could complete the questionnaire anonymously and return the documents to the investigators by mail in a prepaid envelope. If necessary, participants could complete the measures with the help of a significant other (e.g., spouse, family member, or close friend) well acquainted with their day-to-day routine and habits. It was thought that this might help to minimize any biases induced by poor written comprehension or deficits in attention and concentration. Significant others were invited to complete a brief parallel evaluation to corroborate the data provided by the participants. In the overall sample, 28.6% of participants asked for help to complete the measures. The proportion was higher in moderate and severe TBI subgroups (30.9%) than in participants with milder injuries (18.6%). The time required to complete the entire questionnaire (including all measures) varied greatly, ranging from 10 minutes to 5 hours. The mean time for completion was 1.18 hours (71 minutes), and the median was 1 hour.

Measures General Questionnaire. This questionnaire, built for the exploratory purposes of this study, gathered information pertaining to the nature, severity, evolution, and manifestations of fatigue and sleep disturbances associated with TBI. It also addressed topics potentially related to fatigue such as pain and psychological distress. For most questions, participants were asked to reply according to a five-point Likert scale presented visually and adapted to each question (e.g., 0 ⫽ not at all, 1 ⫽ a little, 2 ⫽ moderately, 3 ⫽ very much, 4 ⫽ extremely). Questions specific to fatigue reviewed both past (e.g., before the accident) and present dimensions of fatigue. Seven questions documented the severity, time of onset, frequency, and duration of fatigue. Eight questions dealt with the impact of fatigue on different areas of functioning. One open-ended question related to the hypothesized cause of fatigue, and four items were used to document current nap and rest-taking habits. Finally, three questions pertained to the level of fatigue before the accident. The questionnaire also included questions relating to sleep habits and pain.

In addition to these questions, three validated scales were included in the questionnaire and evaluated the severity of fatigue (Multidimensional Fatigue Inventory), the severity of insomnia symptoms (Insomnia Severity Index), and the level of psychological distress (Indice de de´tresse psychologique de l’Enqueˆte Sante´ Que´bec [Psychological Distress Index of the Quebec Health Survey]). Multidimensional Fatigue Inventory (MFI; Smets, Garssen, Bonke, & De Haes, 1995). This scale is composed of 20 statements for which the responder has to indicate, on a 5-point Likert scale, to what extent the particular item applies to his or her situation in the previous days. The questionnaire measures five dimensions of fatigue: (1) general fatigue, (2) mental fatigue, (3) physical fatigue, (4) reduced activity, and (5) reduced motivation. For each scale, the score varies between 4 and 20, a higher score indicating a higher level of fatigue. The internal consistency and the construct validity of this scale are adequate (Smets et al., 1995). The authors found that the General Fatigue scale is the most sensitive subscale of this instrument. The French-Canadian version (Fillion, Ge´linas, Simard, Savard, & Gagnon, 2003) has been demonstrated to be equivalent to the original version in terms of its psychometric qualities. This scale was chosen because a valid and reliable French-Canadian version is available, which is not the case with other measures such as the Fatigue Severity Scale. Insomnia Severity Index (ISI; Morin, 1993). This seven-item questionnaire yields a subjective yet quantitative index of sleep impairment. On a 5-point Likert scale, participants rate the (1) severity of sleep onset, sleep maintenance, and early awakening problems; (2) satisfaction with their current sleep patterns; (3) interference of their sleeping difficulties with daily functioning; (4) noticeability of impairment attributed to the sleep problem; and (5) degree of distress caused by the sleep problem. The time frame used for completing this measure is the last month. Total scores range from 0 to 28 (0 –7: no clinically significant insomnia, 8 –14: subthreshold insomnia, 15–21: clinical insomnia of moderate severity, 22–28: severe clinical insomnia). The ISI has adequate internal consistency, concurrent validity, and sensitivity to clinical improvements in sleep (Bastien, Vallie`res, & Morin, 2001). The French version of this questionnaire has good internal consistency, appropriate test–retest reliability, and convergent validity with a sleep diary (Blais, Gendron, Mimeault, & Morin, 1997). Indice de de´tresse psychologique de l’Enqueˆte Sante´ Que´bec [Psychological Distress Index of the Quebec Health Survey] (IDPESQ; Enqueˆte Sante´ Que´bec, 1987). This questionnaire is a self-administered French adaptation of the Psychiatric Symptom Index (PSI; Ilfeld, 1976) and has been used extensively in large epidemiological studies in the Quebec population. It contains 29 questions relating to four factors: (1) depression, (2) anxiety, (3) cognitive disturbance, and (4) irritability/anger. Each answer is coded on a 4-point Likert scale (0 ⫽ never, 1 ⫽ once in a while, 2 ⫽ fairly often, 3 ⫽ very often). The sum of scores obtained is divided by the maximum score (87) and multiplied by 100 in order to obtain a standardized score. The psychometric qualities of the PSI are considered to be adequate, as are those of the French version of this scale (Enqueˆte Sante´ Que´bec, 1987; Pre´ville, Boyer, Potvin, Perrault, & Le´gare´, 1992). Although it was initially decided to use other well-established measures of psychological distress (i.e., Beck Depression and Anxiety Inventories), the use of the IDPESQ was requested by the Ethics Committee in order to minimize potential distress caused by the completion of such measures. Significant Other’s Evaluation questionnaire. This questionnaire included a subsample of the same questions found in the General Questionnaire completed by the person with TBI. It reviewed several dimensions of fatigue and sleep quality. This questionnaire took 5 to 10 minutes to complete.

Data Analysis Frequency and characteristics of fatigue. Descriptive statistics (e.g., means, percentages) were used to document the frequency, severity, nature,

FATIGUE FOLLOWING TBI duration, and impact of fatigue. The total sample was also divided into two subsamples: participants presenting significant fatigue and participants not presenting significant fatigue. Fatigue was considered significant if participants reported on a specific question that they were either very much or extremely more fatigued than before their accidents. Participants were not considered to have significant fatigue if they reported being either less, equally, or a little more fatigued than before their injuries. The two subgroups were compared (with t tests) on several clinical variables (e.g., severity of TBI, depression, anxiety, insomnia, pain). Although the division of the sample was based on a comparison of current and preinjury states, thus potentially including a bias due to poor recall, we believe that this measure of fatigue most adequately represents participants’ perceptions of their level of fatigue. Correlations were computed to examine relationships between different sociodemographic and clinical variables. Factors associated with the presence of fatigue. A logistic regression analysis was carried out in order to determine whether some of the demographic and clinical variables could predict the presence of significant fatigue. Twelve variables were entered in the regression model: sex, age, marital status, TBI severity, time since injury, inability to return to work (all measured by individual questions), depressive symptomatology, anxious symptomatology, cognitive disturbance symptomatology, irritability and anger symptomatology (measured with the IDPESQ subscales), sever-

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ity of sleep disturbances (measured with the ISI), and extent of pain currently experienced (measured with 5-point Likert scale ranging from no pain to extreme level of pain). The sample size was adequate considering the recommended figure of 8 –10 participants per variable for logistic regression (Tabachnick & Fidell, 1996). Because we did not have a specific theory or model suggesting that certain variables contributed more than others to the prediction of fatigue, variables were entered in the regression equation using a stepwise forward conditional procedure. In this type of regression, the entry of variables is based on a statistical decision and not on theory (Tabachnick & Fidell, 1996). The analysis was completed using the Statistical Package for Social Sciences (SPSS), version 10.0, and an alpha level of .05 was used.

Results Table 2 presents sociodemographic and clinical characteristics of the Significantly Fatigued and Nonsignificantly Fatigued subsamples. Table 3 presents correlations among different variables measured in the study.

Table 2 Sociodemographic and Clinical Characteristics of the Significantly-Fatigued and NonSignificantly-Fatigued Subgroups Variablesa Age Sex Female Male Marital status Married/Unmarried couple Single/Divorced/Separated/Widowed Education (years) Declared on permanent disability Time since injury (months) Severity of injury Minor Mild Moderate Severe Insomnia severity (ISI score) Number of naps per week Number of rest periods per week Psychological distress (IDPESQ) Depression Anxiety Cognitive disturbances Anger/Irritability Total score Fatigue (MFI) General fatigue Physical fatigue Mental fatigue Reduced activity Reduced motivation Total score Pain (0–4 scale) Presence Frequency

Nonsignificantly fatigued (n ⫽ 139)

Significantly fatigued (n ⫽ 302)

39.86 (13.90)

40.47 (12.70)

Total sample (N ⫽ 452) 40.22 (13.07)

46 (33.6%) 91 (66.4%)

106 (35.6%) 194 (64.7%)

157 (35.0%) 291 (65.0%)

90 (66.7%) 45 (33.3%) 11.56 (2.50) 52 (37.7%) 112.38 (106.30)

174 (58%) 126 (42%) 11.54 (3.07) 177 (58.6%) 83.90 (79.94)*

176 (39.4%) 271 (60.6%) 11.55 (2.90) 236 (52.3%) 94.18 (90.30)

7 (2.5%) 44 (15.4%) 73 (25.7%) 161 (56.5%) 13.01 (6.63)** 6.88 (6.35)** 16.01 (16.25)**

13 (3.1%) 57 (13.7%) 97 (23.3%) 249 (59.9%) 10.88 (6.88) 5.84 (7.09) 12.97 (16.20)

7.37 (5.68) 5.58 (5.19) 4.11 (2.99) 3.05 (2.53) 22.61 (16.75)

13.59 (6.69)** 11.88 (6.82)** 7.45 (2.91)** 5.49 (3.20)** 44.19 (19.67)**

11.60 (7.01) 9.86 (6.97) 6.39 (3.32) 4.70 (3.21) 37.50 (21.25)

10.37 (3.84) 9.79 (4.30) 10.87 (4.33) 10.10 (3.64) 8.87 (3.56) 49.47 (4.84)

15.69 (2.99)** 13.78 (4.00)** 14.63 (3.61)** 13.08 (3.79)** 11.17 (3.83)** 68.38 (13.55)**

13.98 (4.12) 12.49 (4.49) 13.42 (4.24) 12.07 (3.99) 10.41 (3.90) 62.27 (16.56)

1.09 (1.21) 1.45 (1.38)

1.95 (1.19)** 2.71 (1.32)**

1.67 (1.26) 2.31 (1.46)

6 (4.9%) 12 (9.8%) 23 (18.7%) 82 (66.7%) 6.48 (5.06) 3.74 (8.19) 6.85 (14.63)

Note. Sample sizes include participants for whom there are missing data on certain variables. a Displays mean (standard deviation) for the continuous variables, n (%) for the discrete variables. * p ⬍ .01. ** p ⬍ .001, independent groups t-test comparison to nonsignificantly fatigued subgroup.

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Table 3 Pearson Correlation Coefficients for Continuous Variables Variables

Variables

Fatigue severity (MFI-Gen)

Age

Severity of TBI

Time since injury

ISI score

Anxious sympt.

Depressive sympt.

Cognitive sympt.

Irritability sympt.

Age Severity of TBI Time since injury Insomnia severity Anxious sympt. Depressive sympt. Cognitive sympt. Irritability sympt. Pain

⫺0.09 0.08 ⫺0.17* 0.56* 0.50* 0.53* 0.55* 0.42* 0.46*

⫺0.91 0.12* ⫺0.02 0.04 0.06 0.18* 0.02 0.05

0.18* ⫺0.13* ⫺0.06 ⫺0.03 ⫺0.03 0.02 ⫺0.09

⫺0.07 ⫺0.05 ⫺0.05 ⫺0.09 ⫺0.02 ⫺0.11*

0.55* 0.58* 0.52* 0.42* 0.46*

0.81* 0.62* 0.68* 0.56*

0.67* 0.57* 0.47*

0.57* 0.41*

0.35*

* p ⬍ .05 (two-tailed test).

Characteristics of Fatigue Frequency and severity of fatigue. Among all participants, 94.9% reported being more fatigued than before their accidents. According to our criteria, 68.5% were significantly more fatigued than prior to their injuries, whereas 31.5% were either less, equally, or a little more fatigued than before the TBI. Using a cutoff of 12 on the General Fatigue subscale of the MFI to differentiate participants with and without fatigue, as has been done in previous studies on fatigue in cancer patients (Holzner et al., 2002, 2003), 77% of our sample could have been currently characterized as clinically fatigued. Perception of fatigue by significant others. Most significant others (79.4%) rated fatigue in the same category (significant fatigue vs. nonsignificant fatigue) as the participants themselves, whereas 10.3% judged fatigue to be less severe, and a 10.3% judged it more severe than what was reported by the participant.

Figure 1.

Thus, it appears that participants’ subjective evaluation was in general corroborated by significant others. Nature of fatigue. Mean scores on the different MFI subscales indicate that items in the General Fatigue subscale were the most endorsed by all participants (M ⫽ 13.98, SD ⫽ 4.12). When specific types of fatigue were examined, the Mental Fatigue subscale received the highest mean score (M ⫽ 13.42, SD ⫽ 4.24) followed by Physical Fatigue (M ⫽ 12.49, SD ⫽ 4.49). Items in the Reduced Activity (M ⫽ 12.09, SD ⫽ 3.99) and Reduced Motivation (M ⫽ 10.41, SD ⫽ 3.89) subscales were the less endorsed by participants. Appearance, duration, and time course of fatigue. Only 1.9% of all participants reported that the onset of their fatigue was before the accident. The majority estimated that it appeared either a few days (35.7%), a few weeks (15.5%), or a few months (30.7%) following the trauma. Figure 1 presents the average MFI General

Mean MFI General Fatigue score by time elapsed since injury for the whole sample.

FATIGUE FOLLOWING TBI

Fatigue score for participants categorized by time since injury. The peak level of fatigue was reported by participants having sustained a TBI one to two years (12 to 23 months) before the time of the study. Fatigue severity was negatively correlated with time since injury (see Table 3), suggesting that fatigue is a problem that persists after TBI but seems to improve with time. Daily variations in fatigue. Only 2.5% of all participants reported being either never or rarely fatigued during a typical week, whereas 63.9% reported being fatigued nearly every day or every day of the week. In the General Questionnaire, participants were asked to rate on a 5-point Likert scale (0 ⫽ not at all, 1 ⫽ a little, 2 ⫽ moderately, 3 ⫽ very much, 4 ⫽ extremely) the severity of fatigue they usually felt at different times during the day (e.g., upon awakening, during the morning, around lunch time, during the afternoon, etc.). Figure 2 illustrates the mean fatigue ratings reported. Fatigue was reported to be less severe in the morning and increased steadily as the day passed by with the highest ratings being noted in the evening after suppertime. Relationship of fatigue with clinical variables (see Tables 2 and 3). Fatigue severity as measured with the MFI General subscale score was positively correlated with insomnia severity, all psychological distress scales, and pain ratings. Compared to participants who were categorized as not significantly fatigued, fatigued participants had significantly higher scores on the depression, anxiety, cognitive disturbance, and anger/irritability subscales of the IDPESQ as well as a higher total psychological distress score (p ⬍ .001 for all measures). They also reported significantly more severe and frequent pain (p ⬍ .001) and more severe sleep disturbances as measured by the ISI (p ⬍ .001). Impact of fatigue on different areas of functioning. Interference of fatigue was considered significant if participants indicated, on specifics items in the General Questionnaire, that fatigue affected a particular area of functioning either very much or ex-

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tremely. Among all participants, 25.5% reported that fatigue interfered significantly with their daily routine activities such as eating or personal hygiene, 44.3% that fatigue affected their moods, 57.9% that it interfered with their mental abilities such as memory or concentration, 43.3% that it interfered with social or leisure activities, 44.8% that it interfered with their principal occupation (e.g., volunteer or paid work, studies), and 32.9% that it interfered with their past or present rehabilitation activities (e.g., physiotherapy, occupational therapy). For 38.2% of the sample, participants estimated that their fatigue was either very much or extremely apparent to others in terms of deterioration of their quality of life. Furthermore, 38.6% of the total sample reported being either very much or extremely preoccupied with their level of fatigue. Fatigue and TBI severity. A one-way ANOVA of the MFI General Fatigue subscale score indicated that there were no significant differences in fatigue severity between minor, mild, moderate, or severely brain-injured participants. Naps and rest periods. In the total sample, 96.7% of participants reported that they either never or rarely had to stop their activities to take a nap or rest during the day before their accident. After the accident, 50% noted that they had to stop their activities to rest either nearly every day or every day of the week. Furthermore, 21.9% reported that they took rest periods (e.g., lying down without sleeping) 3 to 7 times a week, and 49.5% needed rests more than 7 times a week. In terms of naps, 21.3% reported never taking naps, whereas 36.2% took naps 3 to 7 times a week, and 19.7% reported napping more than 7 times a week. Compared to participants who were categorized as not significantly fatigued, fatigued participants took on average significantly more naps (6.88 vs. 3.74) and rest periods without sleep (16.01 vs. 6.85) per week (p ⬍ .001).

Figure 2. Mean fatigue ratings (ranging from 0 ⫽ no fatigue to 5 ⫽ extreme fatigue) at different times during the day for significantly fatigued participants.

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146 Factors Associated With the Presence of Fatigue

Data was available for 313 participants (69.4% of the total sample—percent of sample for which all data points were available) to perform the logistic regression analysis. A comparison of the full to a constant-only model indicated that the model was statistically valid, ␹2(12, N ⫽ 313) ⫽ 119.03, p ⬍ .001. A moderate fit was observed between obtained and predicted data (pseudo-R2 Nagelkerke ⫽ .45). The model correctly classified 80.8% of the participants with a sensitivity of 90.5% and a specificity of 57.1%. Table 4 presents the regression coefficients from the final model, Wald statistics, odds ratios, and confidence intervals for each of the potential predictors. According to the Wald criterion, five variables were found to contribute significantly to the prediction of the presence of significant fatigue: a shorter time since the injury (B ⫽ ⫺.005, p ⬍ .01), being declared on long-term disability (B ⫽ .765, p ⬍ .05), a higher level of insomnia (B ⫽ .108, p ⬍ .001), a higher severity of cognitive disturbances (B ⫽ .192, p ⬍ .01), and a higher severity of anxious symptoms (B ⫽ .113, p ⬍ .01). Variables that were not part of the final predictive model were sex, age, marital status, TBI severity, depressive symptomatology, irritability and anger symptomatology, and pain.

Discussion The first objective of this study was to estimate the frequency and severity of fatigue in a heterogeneous sample of individuals with postacute TBI. Although almost all participants reported being more fatigued than before the accident, significant fatigue was found to be a complaint in 68.5% of all individuals. This figure is somewhat higher than that reported in studies which have examined fatigue among a variety of residual symptoms following TBI. It is important to note, however, that the bulk of these studies involved individuals with minor TBIs and were conducted mainly in the first year following the accident. This study represents the first effort to concentrate specifically on fatigue and to characterize this symptom in a sample of persons with TBI of varying levels of injury severity and covering a broad span of time elapsed since the injury. Hence, it appears that a very large proportion of persons with TBI complain of significant fatigue, even many years after their accident. A second objective of this study was to describe different characteristics of fatigue following TBI. When using the MFI, mental fatigue was found to be the most prominent type of symptom, followed by physical fatigue. Symptoms relating to a reduced level of activity and motivation also characterized the general

sensation of fatigue, although they were endorsed at a lower level. Fatigue following TBI thus involves several dimensions but could be best described as a general sense of reduced energy and as fatigue felt more particularly at the cognitive or mental level. Fatigue generally appeared either a few days or a few months following the accident, indicating that it is clearly a consequence of TBI rather than a preexisting condition. The most severe levels of fatigue were reported by individuals who sustained TBI between one and five years prior to this study. Although crosssectional in nature, our results suggest that the severity of fatigue generally decreases as time since the injury goes by. A longitudinal examination of the evolution and time course of fatigue following TBI would confirm this claim. Nonetheless, fatigue persists in time for many individuals and is still widely endorsed even many years after the TBI. For most participants, fatigue was present nearly every day or every day of the week. In general, it was least severe upon awakening and gradually increased during the day with the peak level of fatigue reported being in the evening. These results confirm the general clinical impression suggesting that persons having suffered TBI function better during the morning than during the afternoon. Our data thus support the recommendation clinicians may give to their clients to plan activities requiring the most mental or physical energy in the morning rather than in the afternoon to maximize effectiveness and satisfaction, and minimize errors or occupational hazards. Thereby, if a person with TBI is encouraged to resume work or studies gradually, morning shifts should probably be recommended to start with. A reorganization of leisure and social activities taking into account daily variations in fatigue might also help the person with TBI to resume and benefit from such activities that they might have put aside because of fatigue. The results of the present study start to uncover the probable impacts of fatigue on the day-to-day functioning of individuals with TBIs. Indeed, a large proportion of our participants felt that fatigue interfered significantly with their moods, mental capacities, social or leisure activities, or principal occupations, be it work, studies or ongoing rehabilitation. Furthermore, significantly higher levels of insomnia, pain, and psychological distress were found in participants with fatigue compared to those who were not significantly more fatigued than before their accidents. Although these results do not imply a causal relationship, they nonetheless strongly suggest that fatigue probably has important and widespread impacts on the functioning, well-being, and quality of life of after TBI.

Table 4 Results of the Logistic Regression Analysis (Final Model) for the Prediction of Significant Fatigue Predictor

B

Wald ␹2

Odds ratio

95% CI

Time since injury Inability to work Anxious symptomatology Cognitive disturbances symptomatology Insomnia severity

⫺0.005 0.765 0.113 0.192 0.108

9.860** 5.759* 9.310** 8.909** 13.318**

0.995 2.149 1.120 1.211 1.114

0.991–0.998 1.151–4.014 1.041–1.204 1.068–1.373 1.051–1.180

* p ⬍ .05.

** p ⬍ .01.

FATIGUE FOLLOWING TBI

The extremely frequent need to take rest periods or naps further illustrates the impacts of fatigue on functioning in this population. For many TBI survivors, having to stop their activities frequently to rest because of excessive fatigue may be one of the most important barriers to returning to work or to school, because they can no longer keep up with regular professional or academic schedules that do not allow much time for rest. Employers or teachers who know little about TBI may also interpret behaviors such as napping or taking frequent breaks as a lack of motivation or even laziness. Further research describing the importance and impact of post-TBI fatigue may help foster a better understanding and acceptance of this problem on the part of employers, teachers, friends, and relatives of persons with TBI, and thus perhaps smooth out the rehabilitation process by encouraging a more flexible reorganization of goals, activities, and schedules. The third objective of this study was to identify factors associated with the presence of fatigue using a logistic regression analysis. Several factors were found to contribute to predict the presence of significant fatigue. In line with previous studies and with our descriptive results, a shorter time since the injury was predictive of the presence of fatigue, further demonstrating that fatigue tends to lessen as years go by after the accident. This is an encouraging result for persons with TBI, although it nonetheless appears that fatigue still is a common complaint even more than 10 years after the injury. Participants who were declared on long-term disability were more likely to report significant fatigue. Although it makes intuitive sense to assume that individuals with TBI may be unable to work in part because of excessive fatigue, the inverse relationship may also be possible. Being unable to work most probably induces inactivity, frequent napping or rest-taking, and the lack of a regular routine (i.e., getting up and preparing for work every weekday), factors which might actually contribute to fatigue. Indeed, in the chronic fatigue syndrome literature, it has been proposed that fatigue is perpetuated by a vicious circle of inactivity, physical deconditioning, myalgia, and depression, which leads to even more fatigue and inactivity (Klonoff, 1992). Although still scarce, there is some evidence to suggest that cognitive– behavioral interventions involving gradual increases in activity can be beneficial to persons suffering from chronic fatigue (Butler, Chalder, Ron, & Wessely, 1991; Sharpe et al., 1996), a result that might also apply to the TBI population. Suffering from sleep disturbances was found to be significantly related to the presence of fatigue. Fatigue is one of the most prominent consequences of sleep disturbances and appears in a wide range of sleep disorders (Lichstein, Means, Noe, & Aguillard, 1997). Reports of fatigue almost systematically accompany insomnia complaints. Because between 30 and 70% of individuals with TBI report being affected by some insomnia symptoms, and about 30% fulfill the criteria for an insomnia syndrome (Ouellet, Savard, & Morin, 2004), insomnia probably plays an important part in causing or exacerbating post-TBI fatigue. Measures of cognitive disturbances were also found to be associated with the presence of significant fatigue. This result fits well with our finding that mental fatigue was the most prominent type of fatigue reported. It also corroborates previous reports of an association between fatigue and self-reported cognitive symptoms (Bohnen, Twijnstra, & Jolles, 1992; Cicerone & Kalmar, 1995; Kischka, Ettlin, Heim, & Schmid, 1991). There exists an abundant

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literature describing the different cognitive deficits induced by head trauma. A variety of cognitive functions can be impaired following TBI, problems with speed of processing, attention, vigilance, executive functions, learning, and memory being particularly common (McAllister, 1992). Mental fatigue may result from increased or inefficient cognitive activity when individuals try to sustain or divide attention, deal with simultaneous cognitive tasks, or strive to mentally organize or retrieve information. Finally, anxious symptomatology was found to be associated with the presence of fatigue. It can be hypothesized that anxiety can result from a constant need for individuals with TBI to compensate for their deficits in order to cope with demands from their environment. The logistic regression model explained only 47% of the variance. It is thus clear that many other variables not included in the model may have contributed to explain the presence of significant fatigue following TBI. For example, the duration of coma or the localization of cerebral lesions might have had a predictive value. Heavy rehabilitation schedules, medications, extent and quality of social support, stressful life events, genetic factors, and involvement in litigation could also have been found to be linked to the presence of fatigue. Several variables were not found to be associated with fatigue, although it made intuitive sense to expect that they would. For example, TBI severity was not found to be predictive of the presence of significant fatigue. This result suggests that fatigue is not proportional to the severity or extent of detectable brain damage. Thus, it seems that any significant blow to the head, be it considered minor or severe, may lead to post-TBI fatigue. This result fits with the literature on other neurological conditions indicating that fatigue does not seem related to the severity of neurological abnormalities (Ingles et al., 1999; van der Werf et al., 1998). The present study suggests that in addition to possible physiological factors, the development and maintenance of fatigue is probably also associated with behavioral, cognitive, and emotional factors such as inactivity, sleep disturbances, cognitive inefficiency, or overload, and the resulting anxiety. If multiple interacting factors contribute to post-TBI fatigue, it comes as no surprise that fatigue has impacts on various functional levels (e.g., decreased endurance, changes in mood, decreased social and leisure activities, problems with attention and memory). A broad perspective is thereby needed to capture fully the essence of TBI fatigue, and any effective intervention approach should probably involve multiple (i.e., biological, psychological, social) components. For example, a combination of gradual physical reconditioning, cognitive restructuring, cognitive training, gradual increase in social or occupational activities, anxiety-reducing strategies, and teaching of proper energy management techniques could prove beneficial to persons having sustained TBI. Such a cognitive– behavioral approach could also be combined to appropriate medications to treat fatigue, such as antidepressants or psychostimulants. Unfortunately, research on the pharmacological management of fatigue— be it related to any medical condition—is also still in its infancy, and large controlled clinical studies are still needed to determine which agents are most effective in relieving fatigue. Several methodological limitations must be taken into consideration when interpreting the results of this study. First of all, the present data are based entirely on subjective reports that were not

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corroborated either by medical records or face-to-face clinical interviews. Caution is thus warranted in interpreting the present data because some variables may have been biased by poor recall or subjective impressions. Nonetheless, we believe that participants’ perceptions of their conditions are most representative of the impact and distress caused by fatigue. We must assume that recall or perception errors related to self-report are inherent to this type of research. Second, the present sample does not represent the entire TBI population because minor and mild injuries compose approximately 75% of all cases (Kraus, 1993). Yet, these individuals are more difficult to contact since they often pass rapidly through the health care system and do not participate as actively in TBI associations. Third, it might be the case that individuals with fatigue were more motivated to participate in the study, thus leading to a potential overestimation of the frequency of fatigue. Unfortunately, we had no way to compare the characteristics of responders relative to nonresponders. Despite these limitations, this study represents an effort to establish a comprehensive portrait of fatigue following TBI. Our descriptive results clearly highlight the importance of fatigue and will hopefully stir up scientific and clinical interests for this prevalent, severe, and debilitating consequence of TBI which has been ignored in the rehabilitation literature. Despite the fact that fatigue is subjective, difficult to define, and even more difficult to measure, systematic research in this area is nonetheless possible and would greatly benefit individuals who see their mental and physical capacities, as well as their ability to enjoy life, significantly diminished by fatigue. A great deal of research is still needed to pinpoint preventive and therapeutic approaches to this problem. Future studies should focus mainly on evaluating different treatment options for fatigue following TBI (e.g., pharmacological, psychological, combined) because this whole field of study still remains untouched.

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Received March 10, 2005 Revision received September 26, 2005 Accepted December 1, 2005 䡲

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