An exploratory factor analysis of post-concussion syndromes in Thai people after head injury: A psychometric properties study

Abstract

Background: Thousands of patients suffer a head injury in Thailand. Some might recover completely but many
are still at risk of having post-concussion syndromes (PCS) for months or years after injury. PCS has a poor diagnosis. The Rivermead Post-Concussion Symptoms Questionnaire (RPQ) is one of the instruments used
for evaluating PCS.

Objectives: This study aimed to analyze the factors of PCS, and to validate the psychometric properties of RPQ
in Thai people after a head injury.

Method: In a secondary analysis of data drawn from two original studies, 253 head injury patients who visited
Neurosurgical Clinics of King Bhumibol Adulyadej Hospital, and the Police General Hospital, Thailand were recruited. Glasgow Coma Scores of all patients were 13 - 15. Data were collected using demographic and
illness-related questionnaires, and the RPQ.

Results: The RPQ achieved adequate internal consistency with Cronbach’s alpha of 0.88. An exploratory factor
analysis with Varimax Rotation found 4 factors. First, “psychological symptoms” which consisted of seven items,
and three items loaded to factor 2 called “cognitive symptoms”. As for physical symptoms or factor 3, three items,
and three were loaded. Finally, three items corresponded with factor 4 as “vision-related symptoms”. The fourfactor structure was based on the criteria of scree plot, eigenvalue, and factor interpretability in relation to clinical relevance.

Conclusion: This study confirmed both reliability and validity of the Thai-version RPQ. Future studies using a
confirmatory factor analysis in new samples are needed to further assess the psychometric properties of the RPQ.