1.1 Background and Purpose

In recent years, Japan's population has been aging, with the elderly population accounting for 29.1% of the total population in October 2023 [1]. The number of elderly individuals with dementia is also expected to increase significantly, from 4.62 million in 2012 to up to 8.3 million in 2030 [2]. Currently, treatments for dementia involve a combination of pharmacological and non-pharmacological therapies. Among these, non-pharmacological therapy also plays a role in alleviating behavioral disorders and supporting independent living by creating an appropriate living environment. One of the daily challenges for individuals with dementia is disorientation, which can lead to various behavioral and psychological symptoms of dementia (BPSD), such as wandering behavior and incontinence, due to impaired spatial awareness. In this context, group homes for the elderly with dementia (hereafter referred to as GH) are positioned as facilities designed to enable elderly individuals with dementia to live as independently as possible within a communal setting, receiving necessary assistance based on their abilities.¹ As part of this effort, GHs install signs (hereafter referred to as residents' room signs and restroom signs) around the doors of residents' rooms and restrooms to support elderly individuals with dementia in visually recognizing and identifying these locations.

The authors have previously focused on the initiatives of these GHs across two papers, discussing the construction of environments using signs as a medium for elderly individuals with dementia. The first paper [3] clarified the needs of GH caregivers for residents' room signs and identified design elements for residents' room signs targeted at elderly individuals with dementia. The second paper [4], through experimental research involving elderly individuals with dementia, revealed the guiding effects of residents' room signs and restroom signs displayed in GHs. On the other hand, these studies have also revealed differing characteristics between residents' room signs and restroom signs. The second paper [4] identified that retaining “memory” is crucial for understanding the meanings conveyed by residents' room signs and restroom signs. According to classifications of memory in the field of neurology², photographs or personal items used in residents' room signs are categorized as “episodic memory,” whereas text or pictograms, such as the word “restroom,” used in restroom signs are classified as “semantic memory.” These types of memory are affected differently by dementia symptoms, leading to variations in the ability to comprehend the display content. Furthermore, residents' room signs, which rely on episodic memory, are intended to connect with the specific memories of individual residents, while restroom signs require symbols that can be understood by a broader range of residents.

Therefore, this study aims to summarize the needs of facility caregivers regarding restroom signs and to compile design elements for restroom signs targeted at elderly individuals with dementia, as part of ongoing efforts to construct environments with non-pharmacological therapy effects using signs as a medium for elderly individuals with dementia.

1.2 Review of Previous Research

Resources that indicate what types of signs should be displayed as spatial cues for elderly individuals with dementia include the audit tool developed and published by the Dementia Services Development Centre (hereafter referred to as DSDC) at the University of Stirling, UK (hereafter referred to as the DSDC Audit Tool) [5] and the guidelines formulated in 2020 by Fukuoka City with the cooperation of the DSDC (hereafter referred to as the Fukuoka City Guidelines) [6]. The DSDC Audit Tool compiles spatial designs that have been shown to reduce behavioral disorders and promote independent living, based on research findings from around the world, and includes items related to the installation of guidance signs. Similarly, the Fukuoka City Guidelines summarize spatial designs intended for implementation in facilities primarily targeting elderly individuals with dementia, including signs as one of its key components (Table 1).

Major studies on restroom signs displayed in elderly care facilities in Japan include research by Tanaka and Oida [7-9], who conducted a nationwide questionnaire survey targeting elderly care facilities and summarized staff evaluations regarding the status of restroom sign installation and their effectiveness in indicating locations for residents. The survey revealed that approx. 90% of facilities displayed some form of restroom signs, with most combining pictograms and text. Staff evaluations of effectiveness indicated that both “text-based displays such as ‘restroom’ or ‘toilet’” and “pictograms indicating restrooms” were deemed effective for elderly individuals with mild cognitive disorders. Regarding effective display methods, staff highly rated features such as “large text,” “internally illuminated signs,” and “externally illuminated signs.” In contrast, modifications like “changing the color of doors or walls” and “adding directional arrows” received lower ratings, with a preference for intuitive displays becoming apparent. Furthermore, a study using computer-generated (CG) images to evaluate the effectiveness of different types of signs for elderly individuals with dementia [8] reported that text-based displays featuring the words “restroom” or “toilet” were the easiest for residents to recognize.

There is no empirical research demonstrating that displaying pictograms used in restroom signs for elderly individuals with dementia leads to improvements in disorientation or wandering behavior. However, several studies have compiled findings on the ability of elderly residents with dementia to interpret pictograms, aiming to evaluate whether images or symbols, such as pictograms, could serve as alternatives to text-based signs. Okazawa [10] investigated the ease of understanding and retention of three types of pictograms for elderly individuals with dementia: “icons,” which directly depict their meaning through realistic imagery; “indexes,” which represent their meaning using images of related concrete objects; and “symbolic” pictograms, which use abstract shapes or arrows without realistic depiction. The study found that elderly individuals with mild dementia demonstrated comparable understanding and retention abilities to healthy elderly individuals. However, those with moderate to severe dementia struggled to comprehend the meaning of any type of pictogram, and their retention abilities were significantly diminished. Tanaka [11] compared the comprehension of pictograms with the level of care³ and the degree of independence of daily living⁴. The results showed no clear correlation between these factors; however, the study revealed that participants at Independence Level IIIa were able to comprehend pictograms and their meanings. On the other hand, as the study does not address the relationship between the severity of dementia and the readability of signs, it has limitations in demonstrating the effectiveness of the signs. In the process of developing the Fukuoka City Guidelines [7], Fukuoka City conducted a survey on the ability of elderly individuals with dementia to interpret pictograms. The survey revealed that pictograms with representations that are not visually similar to their intended meaning and require prior learning to understand were difficult to interpret. Additionally, it was reported that some individuals focused only on the visual shape or specific parts of the pictogram, failing to grasp the true meaning conveyed by the symbol.

Regarding studies on restroom signs, Namazi [12] reported that the most effective sign for helping individuals recognize the location of a restroom was an arrow on the floor pointing toward the restroom with the word “toilet” written on it. Additionally, another study [13] compared restroom usage between conditions where the restroom was visible from the perspective of elderly residents with dementia and where it was concealed by a curtain. The study found that restroom usage increased eightfold when the restroom was visible. These findings suggest that restroom signs should not only be designed for visibility at close range but should also consider ease of recognition from a distance.

Regarding studies on the visibility of signs, Tanaka [14] reported that there were no significant differences in color discrimination ability associated with cognitive levels among individuals with dementia. However, as age-related conditions such as cataracts and glaucoma can lead to acquired color vision deficiencies, the introduction of color universal design should be considered.

Although there are no studies specifically addressing text size in relation to dementia, text size is generally determined based on viewing distance. For example, an experiment by Akase [15] involving healthy individuals, including elderly participants, found that with a visual acuity of 0.5 or higher, a character height of 4 cm for a viewing distance of 10 m and 8 cm for a viewing distance of 20 m was sufficient for the majority of participants to read without difficulty. In addition to these, cases have shown that placing items associated with the pre-dementia memories of residents increases the likelihood of locating their rooms [16], while combining orientation training with environments featuring three-dimensional, large-scale signs such as pictures or objects improves spatial orientation [17], highlighting the need to consider unique theories for sign planning targeted at elderly residents with dementia, which differ from general principles.

On the other hand, several challenges remain. The DSDC Audit Tool has been criticized for a lack of robust evidence, as the foundational literature review suffers from insufficient sample sizes and the absence of adequate comparison groups. The Fukuoka City Guidelines, while based on international research and feedback from elderly individuals with dementia and adapted by experts to align with Japanese living environments, require future research reports targeting facilities where they have been implemented to confirm their actual effectiveness. Furthermore, although existing studies on restroom signs in Japanese facilities provide useful insights for planning directions, they have not verified outcomes such as the effectiveness of preventing wandering behavior after implementation. In this context, our second paper [4] clarified the characteristics of wandering behavior in elderly residents with dementia and the effects of signs. It was observed that residents with moderate dementia exhibited wandering behavior, where they could head toward the general location or direction of the restroom but struggled to pinpoint its exact location upon arrival. This often led to actions such as opening adjacent doors or searching aimlessly. In contrast, restroom signs intentionally displayed by staff for resident use—placed at a height of 1300 to 1400 mm and featuring text-based labels such as “toire” (toilet) or “otearai” (restroom)—were found to effectively reduce wandering behavior. Based on these findings, this paper aims to summarize appropriate design elements for restroom signs designed to guide elderly residents with dementia. It consolidates the fundamental needs required during the planning process and the conditions related to display content and placement plans based on restroom signs currently in use. Furthermore, it compares these conditions with the specifications outlined in the DSDC Audit Tool and the Fukuoka City Guidelines.

2.1 A Questionnaire Survey Aimed at Identifying the Needs for Restroom Signs (Survey A)

2.2 Field Survey for Identifying Specifications Related to Restroom Signs (Survey B)

2.2.1 Survey Target

The survey targeted eight facilities (18 units) randomly selected from 45 facilities that responded, “available for continued research” in the questions from Survey A (Tables 3 and 4). Each GH facility is equipped with two or three restrooms accessible to residents in shared spaces.⁸ Generally, residents in GH facilities are elderly individuals with mild to moderate dementia who are capable of living independently. However, even when dementia progresses after moving in, residents often continue to live in the units due to factors such as the inability to transfer to a dedicated facility or family preferences, resulting in a few residents with severe dementia within the units. Similarly, in Survey B, some units in each GH included residents with severe dementia and those who use wheelchairs.

TABLE 3. Overview of target facilities (survey B).

Name of group home	Average level of care (requiring long-term care level)	Number of residents		Date opened	Photograph date	Interview date
		Male	Female
WA
Unit 1	2.4	4	5	Apr. 1, 2014	Jul. 24, 2015	Nov. 30, 2015
Unit 2	2.6	3	6
Unit 3	2.8	3	6
KI
Unit 4	2.5	1	8	Mar. 15, 2011	Jul. 30, 2015	Dec. 9, 2015
Unit 5	1.7	1	8
SI
Unit 6	2.5	1	8	Feb. 2, 2011	Jul. 27, 2015
Unit 7	3.6	0	9
YU
Unit 8	2.7	0	9	Nov. 1, 2010	Jul. 15, 2015	Dec. 9, 2015
Unit 9	2.3	0	9
JY
Unit 10	3.1	2	7	Apr. 1, 2006	Oct. 2, 2015	Dec. 11, 2015
Unit 11	2.9	2	7
YA
Unit 12	3.3	0	9	Oct. 1, 2004	Jul. 16, 2015	Dec. 2, 2015
KA
Unit 13	3.8	1	5	Aug. 1, 2004	Sep. 17, 2015	Dec. 2, 2015
Unit 14	3.5	1	5
Unit 15	3.0	1	5
MO
Unit 16	3.3	0	9	Oct. 1, 2003	Sep. 29, 2015	Dec. 22, 2015
Unit 17	3.2	0	9
Unit 18	2.8	1	8

TABLE 4. Overall and restroom floor plans of the surveyed facilities (survey B).

3.1 Current State of Restroom Signs

The presence or absence of restroom signs and the combined use of different types of signs in each GH were summarized as shown below (Figures 1 and 2). The results revealed that 90% of GHs displayed some form of sign to identify restrooms. Analyzing the number of GHs by displayed content, “text-based signs” were displayed in 85 GHs (79%), indicating high demand as they were commonly used across many facilities. In contrast, “pictograms” were displayed in only 56 GHs (52%). Examining the combined use of different content types in restroom signs, only nine GHs (8%) displayed “pictograms” alone, while nearly all GHs with restroom signs tended to include text-based signs alongside pictograms.

3.2 Primary Target Audience for Restroom Signs

The primary target audience for restroom signs was summarized by displayed content (Figure 3). The results showed that for both text-based signs and pictograms, “residents” were overwhelmingly identified as the target audience, with responses ranging from 88% to 93%. Responses indicating “visitors” as the target audience were relatively high at 36%–46%, likely because restrooms within the units are also used by visitors. On the other hand, only 23%–30% of responses indicated “staff” as the target audience. These findings suggest that GH staff primarily consider residents as the main target audience for restroom signs, while visitor usage is regarded as a secondary effect.

3.3 Purpose of Displaying Restroom Signs

For GHs that identified “residents” as the target audience for restroom signs, the primary purposes of the sign were summarized by content type (Figure 4).

The results showed that responses for “provide an understanding of location” ranged from 81% to 85%, while “assist reaching destination alone” ranged from 62% to 68%, with similar trends observed for both text-based signs and pictograms. These findings suggest that the role of restroom signs in GHs is to serve as a cue for residents to identify locations and to assist their independent movement to restrooms as much as possible. Previous papers [6, 10] have indicated that elderly residents with dementia tend to have difficulty interpreting pictograms. However, the results of Survey A showed no significant differences in the stated purposes of display between text-based signs and pictograms. As mentioned in Section 3.1, this is likely because pictograms are often displayed alongside text-based signs, which may influence their effectiveness. For the “other” category, responses for both text-based signs and pictograms included “depends on the user,” indicating that needs may vary depending on the progression of dementia.

4.1 Classification of Restroom Signs

The restroom sign content displayed in each GH was summarized (Table 6). Restroom signs in the surveyed GHs were classified into two categories: restroom signs planned and installed by the designers at the time of the building's construction (referred to as “existing signs”) and those displayed by staff after the facility's opening (referred to as “additional signs”). Among the 18 units surveyed, 15 units had additional signs. In eight of these units, despite the presence of existing signs, staff had added additional signs, resulting in restroom signage being duplicated. Excluding Facility SI (Units 6 and 7), where interviews could not be conducted, staff members from units with additional signs were interviewed about their evaluation of existing signs. The reasons cited for installing additional signs included “inappropriate display content,” “display position is too high,” and “no existing signs installed (despite the necessity of restroom signs)” (Table 7). This suggests that the installation of additional signs is driven by the inadequacy of existing signs in meeting the visibility requirements for individuals with dementia. Furthermore, when staff at GHs with additional signs were interviewed about their effectiveness, all respondents reported that the additional signs had a certain level of effectiveness in guiding residents.

TABLE 6. Examples of restroom signs in each GH (survey B).

TABLE 7. Problems with existing signs (survey B).

4.2 Examination of the Display Contents of the Restroom Signs

4.2.2 Display Methods for Text-Based signs

4.2.2.1 Font Size

Previous papers [7, 9] have highlighted the importance of displaying large text in restroom signs based on staff evaluations⁹. Additionally, in Section 4.1, one of the reasons cited by staff for installing additional signs was the small size of the text on existing signs. This indicates that font size is a critical specification to consider when planning restroom signs. Therefore, the font sizes of text-based signs displayed in each GH, based on both existing signs and additional signs, were analyzed to determine font sizes suitable for visibility by elderly residents with dementia.

The font size of existing signs had a median of 39 mm (approx. 111 pt¹⁰), while additional signs had a median font size of 55 mm (approx. 157 pt). This indicates a tendency for staff to use larger text in additional signs to make them easier for residents to identify (Figure 5). Furthermore, an analysis of the relationship between the level of care in each unit and the font size of restroom signs showed a trend where larger font sizes were used as the level of care increased (Figure 6). Based on the analysis of additional signs, the font sizes of restroom signs showed a concentration between 48 mm and 55 mm for the lower limit, suggesting that a font size of approx. 50 mm (approx. 143 pt) is appropriate. For the upper limit, there was variability, as each interval from the maximum value to the third quartile and from the third quartile to the median was about 35 mm, showing a relatively even distribution. On the other hand, as indicated in our second paper [4], the primary target for restroom signs should be elderly individuals with moderate dementia that generally correspond to a level of care around 3. According to Figure 6, the font size distribution for residents with a level of care around 3 ranged approx. between 30 mm and 90 mm. Therefore, it can be inferred that a maximum font size of around 90 mm (approx. 257 pt) would accommodate the progression of dementia effectively.

Additionally, the frequent placement of restrooms at the end of hallways in GHs, the visibility of door-mounted signs from a distance, the tendency to use large font sizes, and the presence of protruding signs in Units 3, 4, and 17 all suggest that restroom signs may have been designed with consideration for long-distance visibility. Indeed, signs indicating the names of restrooms or similar facilities are reported to serve a guiding function from a distance when they are highly distinguishable.¹¹ Furthermore, Namazi's study [13] observed a tendency for restroom usage to increase when restrooms were visible from a distance. Considering font sizes for long-distance visibility, Akase [15] proposes an 80 mm font size as a standard for a viewing distance of 25 m. Based on this, font sizes ranging from approx. 50–90 mm (approx. 143–257 pt) would likely ensure adequate visibility even in facilities the size of GHs. In conclusion, when examining font sizes based on additional signs, a range of 50–90 mm, adjusted according to viewing distance, appears to be appropriate.

4.2.2.2 Font Type

The usage trends of fonts in text-based additional signs were analyzed. First, an overview of the production methods for text-based additional signs showed that 19 cases (51%) were printed, while 18 cases (49%) were handwritten or created using non-print methods (Figure 7). Next, the fonts used in printed text-based additional signs were categorized into “serif fonts,” “sans-serif fonts,” “brush script,” and “design fonts”¹². The analysis revealed that “serif fonts” were used in 10 cases (53%), while “sans-serif fonts” were used in seven cases (37%) (Figure 8). Although there was no significant difference in the usage rates of serif and sans-serif fonts, sans-serif fonts, with their uniform line thickness, are generally considered more legible for signage¹³. However, as restroom signs in additional signage tend to use large font sizes, it is likely that readability is ensured primarily through font size rather than font type.

4.2.2.3 Background and Text Color

The selection tendencies for background and text colors in additional signs were summarized (Table 8). The most common combination observed was a white background with black text, accounting for 62%, while other color combinations were used in significantly smaller proportions. Additionally, only combinations with light backgrounds and dark texts were utilized, while combinations with dark backgrounds and light texts were not observed. In general, greater lightness contrast between the background and text is considered to enhance visibility¹⁴, and this study also observed a tendency to adopt color combinations with significant lightness contrast. On the other hand, many printed additional signs were created by printing black text on white printer paper, suggesting that the creation process also influenced these results.

TABLE 8. Trends in selection of background color and text color.

	Text color (%)
	Black	Blue	Red	Brown	Multi colored
Background color
White	62	3	5	0	3
Yellow	5	0	0	0	0
Light blue	3	3	3	0	0
Light red	0	0	3	0	0
Light brown	0	0	0	5	0
Wood (dark brown)	0	0	3	0	0
Multicolored	3	0	0	0	0

• Note: N = 37.

4.3 Examination of the Layout Plan for Restroom Signs

4.3.1 Display Height

As noted in Section 4.1, one of the reasons staff cited for installing additional signs was the inappropriate display height of existing signs, which hindered residents' visibility. To examine a display height suitable for individuals with dementia, the visual height during hallway movement with independent walking was analyzed based on the average eye height and visual field range of men and women over 80 years old¹⁵ (Figure 9). The visual height was then compared with the display heights of existing signs and additional signs in each GH to determine appropriate display heights. It should be noted that protruding restroom signs, which were intentionally placed at high positions for long-distance visibility, were excluded from this analysis.

When considering visibility while moving down a hallway using a handrail, the average visual field range for men and women at a distance of 400 mm from the wall includes an eye height of 1329 mm, an appropriate range of display devices of 1169–1400 mm, and color discrimination limits of 1064–1631 mm (Figure 9). In comparison, the median display height of existing signs is 1507 mm, indicating a tendency for signs to be displayed higher than the appropriate range of display devices for residents (Figure 10). On the other hand, the median display height of additional signs is 1383 mm, which falls within the appropriate range. Furthermore, additional signs tend to cluster on the upper side of the appropriate range of display devices, from the third quartile (1422 mm) to the first quartile (1305 mm). An analysis of the relationship between the display height of additional signs and the average level of care showed no bias or correlation, suggesting that changes in display height due to increased care levels are minimal (Figure 11). Based on these findings, when planning the display height of restroom signs using additional signs as a benchmark, a height of approx. 1300–1400 mm is considered appropriate.

4.3.2 Display Position on the Surface

Based on the display positions of restroom signs installed around restroom doors in GHs, the suitability of display positions for visibility by elderly residents with dementia was examined (Figure 12). The display position of restroom signs, both existing and additional, was most commonly on the door surface. In Japanese GHs, where doors are aligned in close proximity with narrow spacing, displaying signs on the door surface is likely considered the most effective for identifying their location. In the case of residents' room signs, products that can be used to replace names are sometimes used, and residents' personal items¹⁶ are sometimes placed, so there is a tendency for the sign itself to have a lot of depth. Consequently, these signs were often unsuitable for installation on sliding door surfaces [3]. In contrast, restroom signs had a lower need for content replacement and showed no evidence of decorative elements being displayed. As a result, the thickness of these signs was minimized, making it possible to install them on door surfaces.

In contrast, in the case of Unit 3, the sliding door lacked a stopper function, posing a risk of residents tripping on doors that closed automatically. As a result, the restroom door was routinely kept open during operation. Consequently, the door surface could not be used as a display area, and restroom signs were instead displayed on the surrounding wall surfaces. Based on the above, the door surface is considered the most appropriate display position for restroom signs aimed at visibility by individuals with dementia. However, it is important to note the potential for operational scenarios where doors are kept open due to functional issues. In such cases, displaying signs on the surrounding wall surfaces must also be considered.

4.3.3 Relationship between Existing Sign and Additional Sign Display Positions

The positional relationships between existing signs and additional signs, in cases where both were displayed together for restroom signage, were categorized to identify trends (Table 9, Figure 13). Note that four protruding restroom signs were excluded from the analysis as they were designed for long-distance visibility. Overall, both existing and additional signs were frequently displayed on door surfaces, making Case 7 the most common. Additionally, four restroom signs in Units 11 and 13 corresponded to Case 5, where text-based additional signs were displayed directly below existing pictogram signs. These existing signs were displayed at heights of 1425 and 1543 mm, which are close to the optimal range. This suggests that staff may have added information to the existing signs by displaying the additional signs in a complementary manner.

TABLE 9. Classification of positional relationship between existing signs and additional signs.

4.4 Comparison of Design Elements

As noted in Section 1.2, the DSDC Audit Tool and the Fukuoka City Guidelines include guidance on signage as part of their recommendations for spatial design aimed at supporting individuals with dementia. In contrast, the authors discussed the design elements for residents' room signs in our first paper [3] and examined the specifications for restroom signs in this study. In this section, the design elements for these different types of signage are compared to identify differences and key characteristics (Table 10).

5.1 Needs for Restroom Signs Designed for Elderly Individuals With Dementia

Restroom signs were found to be displayed in 90 of the GHs surveyed. Among these, text-based signs were displayed in 79 of GHs, indicating a high prevalence. Pictograms were observed in 52 of GHs; however, only 8 of GHs used pictograms exclusively, with most cases combining them with text-based signs.

The primary roles of restroom signs in GHs are to serve as visual cues for residents to identify locations and to support independent movement to restrooms as much as possible. Additionally, as a secondary effect, the use of visitors is also taken into consideration.