Reliability and validity of Questionnaire for Neurobehavioral Disability following traumatic brain injury


Michihiko Yamasato, MD, Department of Psychiatry, Tsukuba Memorial Hospital, 1187-299 Kaname, Tsukuba, Ibaraki-ken 300-2622, Japan. Email:


Abstract  The neurobehavioral disability recognized in traumatic brain injury (TBI) is a severe sequela, but there is no appropriate classification due to its various manifestations. In the present study a questionnaire for a simple investigation of this disability was prepared, and its reliability and validity verified. The survey was conducted on 72 patients with TBI by the caregiver of each patient. As a result, good reliability was indicated by the split-half method (coefficient of reliability: 0.95, obtained using Spearman–Brown correction formula). The total score of the questionnaire had a significant correlation with the total score of the simultaneously conducted Japanese version of Neuropsychiatry Inventory at the 0.01 level (Spearman's rank correlation, 0.47). It also had a significant correlation with the total score of the simultaneously conducted Japanese version of the Dysexecutive Questionnaire at the 0.05 level (Spearman's rank correlation, 0.36). Six factors constituting this neurobehavioral disability were extracted from a factor analysis of the questionnaire survey. These factors are angry outburst, avolition, deficits of sympathy, depressed mood, discourse deficits, and degradation of appearance. Each factor indicated good internal consistency (Cronbach α, 0.86–0.94). The present results indicate that this questionnaire has good reliability and validity, therefore it can be a significant indicator in TBI neurobehavioral disability study.


It is known that various psychotic manifestations occur in association with traumatic brain injury (TBI).1,2 In particular, neuropsychiatric manifestations continuing after the chronic phase are defined as head injury sequelae3 and are classified into the six following types: (i) manifestations, mainly autonomic nervous system dysfunction (headache, dizziness, numbness, sleep disorder, lack of concentration, easy fatigability);4 (ii) intellectual function disorder (aphasia, apraxia, agnosis, memory disorder);5 (iii) neurobehavioral disability such as personality change; (iv) manifestations similar to schizophrenia (hallucination, delusion);6,7 (v) traumatic epilepsy; and (vi) traumatic neuropathy.

Among these sequelae, neurobehavioral disability such as personality change in particular, has been investigated.8 According to Thomsen, two-thirds of young TBI patients have shown neurobehavioral disability,9 which distresses their family (caregivers), and causes serious problems.10

Therefore, intervention such as drug administration or behavioral therapy is required as well as empiric evaluation. However, neurobehavioral disability is difficult to classify because personality change following TBI is diverse and irregular, and it is also difficult to set the boundary between normal and abnormal.

Regarding neurobehavioral disability, Prigatano has classified personality change occurrences in TBI into three types: active manifestations (irritability, agitation, belligerence, anger, impulsiveness, impatience, restlessness, inappropriate social response etc.), passive manifestations (aspontaneity, sluggish, loss of drive or initiative, tires easily, depressed etc.), and syndromes (childishness, lack of insight or awareness etc.).11 However, this classification is not necessarily appropriate for evaluating each factor and developing methods for treatment interventions, because this classification was only arranged from retrospective studies. In addition, caregiver viewpoint is important when evaluating detailed personality change because they observe the real life of patients in detail. However, it is not included.

Therefore, we carried out a questionnaire survey on neurobehavioral disability among caregivers of TBI patients in order to solve these problems. First we investigated reliability and validity. Second we carried out factor analysis. Through such investigations, further detailed assessment of personality change and setting of rational target manifestation will become possible.



First, TBI was defined as a head injury with loss of consciousness at the time of injury.12 The study subjects consisted of 60 male and 12 female TBI patients who visited Tsukuba Memorial Hospital, Higher Brain Function Outpatient Department or Saitama Prefectural General Rehabilitation Center, Neuropsychiatry Outpatient Department during 2 years from April 2004. The patient age range was 10–63 years (mean age: 38.3 ± 17.1), with an average period of 24.3 days for loss of consciousness, an average education period of 13.7 years and an average period of 5.8 years from the time of injury to the survey.


Based on the items used in the Japanese version of the General Health Questionnaire (GHQ)13 and the Japanese version of the Dysexecutive Questionnaire (DEX-J),14 a total of 97 preliminary questions about the neurobehavioral disability were created. The questionnaire required close family members of the patients to select the most appropriate answer for each question from three answers (yes, no, unknown).

Among the preliminary questions, 50 items that were appropriate for this questionnaire were selected (Appendix I).

Statistical analysis

For verification of reliability by the split-half method, these 50 items were split into two groups of odd numbers and even numbers to obtain a correlation coefficient between the scores of two groups, which was substituted with the Spearman–Brown correction formula to obtain the coefficient of reliability. Additionally, for verification of validity, DEX-J and Neuropsychiatry Inventory–Japanese version (NPI-J) were also conducted simultaneously to obtain Spearman's rank correlation.

Factor analysis (principal factor method, varimax rotation for eigenvalues >1) was carried out. Fifty items were selected from the preliminary questions with factor loading >0.46. In this condition, no item belonged to plural factors. SAS Learning Edition 4.1 (SAS Institute, Cary, NC, USA) was used.

The present study was approved by the Tsukuba Memorial Hospital Ethical Committee.



The correlation coefficient between two groups of odd numbers and even numbers obtained using the split-half method was r = 0.90, and the coefficient of reliability obtained by substituting the correlation coefficient in Spearman–Brown correction formula was ρ = 0.95.


In verification of validity, Spearman's rank correlation between the total score of this questionnaire and NPI-J and DEX-J were 0.47 and 0.36, respectively (Table 1).

Table 1.  Spearman rank correlation
  • *

     < 0.05;

  • **

     < 0.01.

  • DEX-J, Dysexecutive Questionnaire–Japanese version; NPI-J, Neuropsychiatry Inventory–Japanese version.

Present questionnaire3874.438.7708145  

Factor structure

The following six factors were extracted (Table 2). Factor 1 (variance of 12.8%) related to ‘angry outburst’. Factor 2 (variance of 14.2%) related to ‘avolition’. Factor 3 (variance of 8.3%) related to ‘deficits of sympathy’. Factor 4 (variance of 7.7%) related to ‘depressive mood’. Factor 5 (variance of 6.4%) related to ‘discourse deficits’. Factor 6 (variance of 4.9%) related to appearance of degradation. The cumulative contribution of these six factors was 54.2%.

Table 2.  Varimax rotation of 50 items of present questionnaire Thumbnail image of


The coefficient of reliability obtained using the split-half method was >0.9. Therefore, it was verified that this questionnaire has good reliability.

Significant correlations were indicated between this questionnaire and the DEX-J at the 0.05 level and the NPI-J at the 0.01 level. For these investigations, Oikawa et al. reported that there was a significant correlation between the DEX-J and Alzheimer's Disease Assessment Scale (ADAS),15 and Hirono et al. also reported that the NPI-J had the same sufficient reliability as the original NPI.16 Accordingly, validity of this questionnaire was verified.

The significance of each factor obtained by factor analysis was discussed. Each factor indicated good internal consistency (Cronbach α, 0.86–0.94).

Factor 1 included items about agitation, impulsiveness, easy stimulability, quick temper and mood swing. Similar factors were also noted by Prigatano (irritability, agitation, anger, episodic dyscontrol)11 and Schneider (hyperirritability, displeasure, explosiveness, violence, lack of control).17 Tateno et al. reported that these disorders of emotional control were observed in approximately one-third of TBI patients, and which may interfere with their social functions and return to work if appropriate measures are not taken.18 The etiology of this disability is considered to be either decreased function of orbital prefrontal cortex19 or excess function of amygdaloid nucleus.20 In the former explanation, the excitation appears when there is no suppression effect in usual social norms, for the reason that natural emotional response to others becomes difficult. In contrast, the latter explains that emotional response for minor external irritation increases, to develop into aggressive behaviors. In both disorders it is considered that the impact is caused by the sphenoid bone pressing on the basal surface of the cerebral hemisphere.18

Factor 2 included items about decreased appetite, decreased initiative and apathy. Similar factors were also noted by Schneider (indifference, decreased initiative, bovinity, opacity)17 and Prigatano (aspontaneity and loss of interest in the environment).11 As for foci of such an avolition, some may be easily caused by damage to the hemisphere inner surface of the frontal cortex3,21 (especially damage to the circuits connecting anterior cingulate gyrus and subcortex),17 and other foci may be caused by damage to the right hemisphere of the brain.22

Factor 3 included items about the lack of theory of mind, emotional recognition and emotional expression disorder. Theory of mind is the ability to make assumptions of various mental states for oneself and others, which is essential to establish basic human relationships.23 The lack of this leads to a state in which so called ‘sympathy’ cannot be performed. Bibby and Macdonald reported that TBI patients presented decreased ability to understand psychological states of others.24 In addition, Milders et al. reported that TBI patients tend to have decreased understanding of other people's emotions, expressed in their facial and body expression and behaviors.25 Some of the lesions related to this factor are located in the prefrontal cortex,23,26 and the others are in a large area of the right hemisphere.27 Concerning the former lesion, Mimura suggests that theory of mind and the function of the prefrontal cortex are intimately related.28 For this, the damage in this area may cause a lack of consciousness of the disease, discourtesy or rude behavior and frequent deviant social behavior. In contrast, for the latter, Ponsford suggested that patients with extensive lesions on the right hemisphere have emotional recognition disorders such as visual impairments and auditory impairments, which means that they can understand sentences spoken by others, but not easily interpret the feelings in their voice tone and facial expressions.27

Factor 4 included items to evaluate the emotional aspect of depression. Depression is a complication frequently recognized in TBI.29 According to Jorge and Robinson, 33% of 91 TBI patients suffered major depression in the first year after injury.30 Such depressed moods are also noted by Prigatano11 (depression, anxiety, sensitivity to distress, catastrophic reaction). As for lesions causing depressed moods, Jorge and Robinson considered that patients with depressed moods had decreased volume of the left prefrontal cortex (especially the ventrolateral side and dorsolateral side), and decreased function of such parts would cause major depression disorder.30 Also, there are reports on the etiology of depressed moods indicating that social and psychological factors are added to organic factors,31 and it has often been witnessed in patients with a previous history of feeling disorder and anxiety disorder.30

Factor 5 included items about periphrases and difficulties in summarizing speech, which corresponded with discourse deficits.27 Patients with discourse deficits tend to talk in a roundabout way and talk about themselves selfishly and endlessly. In the background of these deficits is the disorder of executive function.32 Also Okuma includes circumstantialities and cohesion in TBI personality changes.3 Dennis and Barnes reported that three-quarters of TBI patients had abnormality in some tests for discourse deficit.33 The focus of discourse deficits is considered to be in the frontal cortex.34

Factor 6 included items about maintenance of cleanliness and sanitation such as ‘degradation of appearance’ and ‘dressing’. This factor may evaluate motivated behavioral aspect, but it can also be assumed that lack of self-insight may be the cause.

To conclude, this questionnaire can be a significant indicator in neurobehavioral disability following TBI and in setting up intervention goals to develop practical treatment methods.



Questionnaire for Neurobehavioral Disability

Table 3. Please check one of yes, no, or unknown to indicate the presence of problems.
 1Does he(she) become furious when he gets excited?   
 2Does he get excited by small things?   
 3Does he sometimes get over-angry at the slightest?   
 4Does he continue to nit-pick?   
 5Is he short-tempered?   
 6Does he get irritated by minor things?   
 7Do you think his feelings fluctuating severely?   
 8Is he capricious?   
 9Does he lose his temper at the slightest?   
10Does he take a defiant attitude for no particular reason?   
11Do you find that he has no real desire to do anything?   
12Do you find that he does not have any appetite to do things voluntarily?   
13Do you find that he is doing anything unless someone instructs him?   
14Is it hard for him to do things without instruction by others?   
15Does he easily give up?   
16Do you find that he is lacking in appetite for daily activities?   
17Does he need to be instructed or told what to do due to lack of initiative?   
18Do you find that he is uninterested in things around him?   
19Does he depend on someone for everything just like a child?   
20Do you find that he cannot decide anything alone without an instruction?   
21Do you find that he has no close friends?   
22Does he neglect degradation of his ability?   
23Do you find that he is not aware of how others feel about his behavior?   
24Do you think that he cannot be considerate of a feeling of a partner?   
25Do you find that he is not able to express his feelings?   
26Does he keep changing topics to the extent people cannot cope with it?   
27Do you find it hard for him to maintain friendship with others?   
28Do you find it hard for him to become close to others?   
29Do you find he cannot sense the atmosphere of the situation?   
30Do you find it hard for him to understand the situation he is in?   
31Does he repeat selfish opinions?   
32Does he say selfish things like a child?   
33Does he think that himself is miserable?   
34Has he become unable to have confidence in himself?   
35Does he think that himself is a worthless human?   
36Does he feel the burden of even minor things?   
37Do you find it hard for him to summarize what he wants to say?   
38Does he always talk in a roundabout way?   
39Does he impose upon others by repeating the same things?   
40Do you find that his over-persistence annoys others?   
41Do you find that he does not take care about how to dress?   
42Do you find that he comes not to care about his appearance?   
43Do you think he can no longer be patient?   
44Does he have trouble being patient?   
45Do you find it difficult to change something he insists on?   
46Does he continue being particular when he does not like it?   
47Do you find it hard for him to go back to sleep after waking up too early?   
48Do you find that he does not feel fine in the morning?   
49Does he stay idle all day?   
50Is his daily rhythm irregular?