## 5 Discussion  
The living room of a nursing home (NH) hosting people with BPSD (among other residents) was considered as a case study to test the applicability of a prediction model of ambient noise levels and a simplified equation to determine the acoustical capacity of a space, as proposed by [PERSON] [24]. The original model was developed for eating establishments, and it was validated on different types of facilities, such as bistros, cafeterias and restaurants, and senior residence dining rooms, the latter being the closest type of facility to a NH living room, as included in the AcustiCare project. In particular, for the definition of the acoustical capacity relationship as a function of volume and reverberation time, the Equation (2) assumes a group size value \(g=3.5\), an absorption per person value \(A_{p}=0.35\) m\({}^{2}\), and a reference ambient noise level that does not exceed \(L_{\text{N,A}}=71\) dB to guarantee sufficient quality of verbal communication. However, the living rooms of NHs are quite an extreme case on the spectrum of possible facilities and the results of this study show that if the general formula were to be used with the abovementioned parameters values, the actual acoustical capacity of the NH living room would be overestimated by approximately 65%. The group size \(g\) value is an indicator of the level of arousal of the gathering and for the NH living room it was expected to be much higher than the 3-4 range typically working for average facilities. [PERSON] [24] proposes that for senior residence dining rooms, a group size as high as \(g=8\) should be considered, because the conversation might not be very lively. Results from the present study suggest that, for the specific group of people with dementia (with some of them expressing BPSD) in nursing homes, levels of interaction/conversation might be even lower because of (among other aspects) cognitive impairment, thus leading to higher \(g\) values. Because the levels of arousal are likely to vary at any facility over time, the optimal value for group size \(g\) might change accordingly. In [24], an example is provided for a reception in a public eating establishment where guests are served alcohol: the arousal level could increase with time, leading to a decreasing group size (i.e., more people talking) and increasing noise level with time. To some extent, similar dynamics of arousal and activity  
Figure 5: Picture of the nursing home (NH) living room after the installation of the acoustic floating floor and absorbing ceilings. variations might also be expected in the case of a nursing home. Thus, further research might consider this aspect and test different \(g\) values depending on the activity taking place in the NH living room. Indeed, verbal communication is certainly a key function of the NHs living rooms, but it is not the only function contributing to ambient noise levels, as both Figures 2 and 3 seem to confirm. According to [PERSON] [24], the absorption per person \(A_{p}\) value should range between 0.2 and 0.5 m\({}^{2}\). This is affected by people's behaviour in the environment (e.g., whether they are sitting or standing) and the type of clothes they are wearing. [PERSON] highlights that \(A_{p}\) would have a smaller effect on the accuracy of the model than the actual equivalent absorption area per person in the room, and in the case of seated people, \(A_{p}\) should be considered as the additional amount of absorption compared to the empty chairs. For seated persons wearing light summer clothes, [PERSON] suggests that the lowest value of the range should be considered [24]. The results of this study are in line with this suggestion, and this could be explained by the fact that the majority of NH residents are indeed sitting for most of the time and, being in a domestic environment, they tend to wear lighter clothes than other people would in a publicly accessible facility; the same applies, to some extent, to staff members who wear standard uniform for care personnel.