In the validation study five groups of patients (103 ALS patients, 10 ALS-FTD patients, 25 patients with FTD without ALS, 39 patients with muscle diseases, 31 subjects evaluated at the out-patient neurology clinic for diverging complaints (other controls)) were included.
The patients with ALS-FTD and FTD served as positive controls (n=35); the patients with muscle diseases and the other controls served as negative controls (n=70).
In addition to other clinimetric properties, we examined reliability, clinical validity and construct validity of the ALS-FTD-Q. We compared the ALS-FTD-Q with the Frontal Systems Behavior Scale (FrSBe) and the Frontal Behavioral Inventory (FBI).
We believe that the ALS-FTD-Q measures behavioural changes more precisely than the FrSBE and the FBI in ALS patients, because the effect of motor and speech dysfunction has been minimised in the ALS-FTD-Q. By using the FrSBe and FBI, ALS patients may be falsely qualified as having frontotemporal dementia.
In table 1 the number of patients with mild or severe behavioural changes is shown, as meausured with the different questionaires.
Table 1. Patients with mild or severe behavioural changes.
The preliminary cutoff values are as follows:
Mild behavioural changes: ≥ 22 and < 29
Severe behavioural changes:
≥ 29
In figure 1 the correlation of the ALS-FTD-Q with the FrSBE and the FBI is shown. The blue line represents the correlations with the FrSBe, r = 0.80. The red line shows the correlation with the FBI, r = 0.79. The high correlations indicate that all three instruments measure the same construct, that is frontal-lobe mediated behaviour. The correlation is expressed as Spearman rank correlation coefficient.
Figure 1. Correlation of the ALS-FTD-Q with the FrSBe and FBI.
This boxplot (figure 2) shows the scores of the different groups in our study. The scores of the negative control groups are low, whereas the scores of the ALS patients and ALS-bvFTD patients are high.
Figure 2. Scores on the ALS-FTD-Q.
Reference
1. Raaphorst J, Beeldman E, Schmand B, et al. The ALS-FTD-Q: a new screening tool for behavioral disturbances in ALS. Neurology 2012 Sep 25;79(13):1377-83.
