This study identified nine rehabilitation assessment instruments that have most commonly been referred to in the literature for adults with brain tumors, that covers all components of the ICF, and has good psychometric properties. As far as the authors are aware, this is the only systematic review of assessment instruments used for adults with brain tumors. However, this systematic review did not identify one unique assessment instrument for the target group. This patient group is specific in a way that there is no unifying patient-specific clinical set of symptoms and their symptoms depend on various other factors.(15)
Five of these tools are used for objective assessment: KPS, MMSE, FIM, TMT, BI, four are self-assessment tools: FACT-Br, SF-36, EORTC QLQ-C30, EORTC QLQ- BN20.
The most frequently used assessment instrument is the Karnofsky Performance Scale as it is used as a criterion for the selection of participants by measuring their level of physical activity.(16) This assessment tool is developed for general assessment of oncological patients(17) and reflects overall ability to perform usual daily activities (component of Activities and Participation of the ICF) in the context of help needed from other people (Environmental Factors).
Only three of these instruments are specifically intended for evaluation in patients with brain tumors: EORTC QLQ-C30; EORTC QLQ-BN20; FACT-Br; they are all linked to the quality of life. Moreover, the EORTC team recommends that QLQ-C30 and QLQ-BN20 tools be used together.(18) These two tools cover both functioning components of the ICF and from the perspective of content, complement each other. QLQ-C30 contains more specific questions on problems specific to patients with brain tumors.(19, 20) The QLQ-C30 and the QLQ-BN20 provide comprehensive information about the patient's quality of life, but this is often overlooked in studies identified in this systematic review. The FACT-Br questionnaire has been used less and it has as good properties in terms of intra-rater reliability and structural validity as other two specific quality of life measurements, contains problems that has not been included in any of previous tools, and can clearly be important for this population, such as handling stress or driving a car. It also considers important Environmental factors, such as help and attitudes of family members and friends, as well as health professionals. Some important concepts also overlap with the SF-36 that have developed as a multipurpose tool that is used for assessment of functional health and well-being(21) and has been widely used for patient-reported outcomes in populations with different diagnosis.(22) Therefore, this could be good choice to use the SF-36, if the comparison between populations is needed.
Between the most used assessment tools, the FIM and BI has been listed. As SF-36, these instruments are non-specific to diagnosis, and both have been widely used in different rehabilitation populations.(23–25) Both scales, the FIM and the BI, are performance based assessment tools and both analyze the level of independence in most important activities of daily living, psychometric properties have been profoundly analyzed, and the ceiling effect for the BI can be observed when compared to the FIM.(26) However, the psychometric properties of the objective assessment instruments specific for the patient group have not been proven; therefore, their psychometric properties were demonstrated in patients suffering from stroke, traumatic brain injury (TBI) or similar neurological condition. Interestingly, two neuropsychological assessment tools (the MMSE and the TMT) are mentioned between the most frequently for persons with brain tumors. It can be explained with the fact that cognitive impairments are a common symptom in patients with brain tumors.(4) Both instruments focus mostly on the cognitive functions of the component of the Body Functions and Structures of the ICF and both are performance based. However, the psychometric properties of the MMSE have been better documented.
Using the ICF framework, it was possible to link the majority of elements identified in the assessment instruments to certain categories. Some elements could not be linked since they covered topics such as quality of life, personal factors, or certain elements not defined in the ICF. Body Function categories were dominated by MMSE, TMT, EORTC QLQ-BN20, EORTC QLQ-C30, activity and participation categories – FIM, BI, KPS, but FACT-Br viewed these two domains equally. Environmental factors were assessed by EORTC QLQ-30, FACT-Br, FIM, BI and KPS. Given that the clinical picture of brain tumor patients is similar to that of other neurological conditions, such as stroke(6) or TBI(7), the ICF Core Sets were reviewed for stroke and TBI(27) and their categories were compared to categories identified in this systematic review. Comprehensive core sets for stroke listed 13 categories in body functions and structures, 14 in activities and participation, and 23 categories in environmental factors that were not identified in assessment instruments analyzed in this study. Comprehensive core sets for TBI listed 10 categories in body functions domain, 22 in activities and participation, and 28 categories in environmental factor domain that were not identified in any of 9 assessment instruments analyzed within this study. This can be explained by the fact that the most frequently used assessment instruments do not cover all the possible impairments for people with brain tumors.
Given that the ICF Core Sets for stroke and TBI were compared to categories identified in this review and they proved to be overall covering similar areas it can be concluded that all 9 assessment tools identified in this study can be appropriate and specific assessment instruments for patients with brain tumors, as they have been proven valid, reliable and responsive to a variety of neurological conditions. Further research is recommended to assess reliability, validity, and responsiveness of assessment instruments specifically for brain tumor patient groups.