Domains of Awareness in Young and Late Onset Dementia

Abstract

Background:

There is a lack of research investigating whether there are differences in the domains of awareness according to the age at onset of dementia.

Objective:

This study is designed to investigate differences in awareness of cognitive functioning and health condition, functional activity impairments, emotional state, and social functioning and relationships among people with young onset (YOD) and late onset dementia (LOD); and examine associations between awareness and its domains with cognition, functionality, neuropsychiatric symptoms, social and emotional functioning, and quality of life (QoL) in both groups.

Methods:

A group of 136 people with dementia and their respective caregivers (YOD = 50 and LOD = 86) were consecutively selected. We assessed awareness of disease, dementia severity, cognition, functionality, neuropsychiatric symptoms, social and emotional functioning, and QoL.

Results:

People with YOD had more neuropsychiatric symptoms than people with LOD. People with YOD were more aware of disease (total score), of their cognitive functioning and health condition and of their functional activity impairments, even if this group was more severely cognitive impaired and had a worse level of functionality than LOD group. Multivariate linear regressions showed that functionality has a wide relationship to awareness for people with YOD. While neuropsychiatric symptoms and QoL has a greater relation to awareness for people with LOD.

Conclusion:

Different clinical variables are associated to different domains in YOD and LOD groups, reinforcing the heterogeneity of awareness in dementia.

Keywords

Awareness of disease awareness’ domains dementia late onset young onset

INTRODUCTION

In dementia, awareness can be defined as the recognition of changes caused by deficits related to the disease process, which may include the ability to recognize a specific deficit, the emotional response to the difficulties presented, and the ability to understand the impact of the disease in activities of daily living [1 –3]. Thus, awareness is a multidimensional construct and has three main characteristics: 1) It is not dichotomous as it may vary in degree, from preserved, mildly impaired awareness to a complete denial of a deficit [4]; 2) it oscillates [5]; and 3) it is considered relational since it can only be expressed in relation to something, i.e., an object, such as the pathological state or the non-morbid experience. Therefore, awareness is a concept that must be understood in relation to a given object [6].

In dementia research, there are many objects of awareness that include external stimuli, symptoms of memory problems, or changes in the person’s internal states [6], a combination of cognitive impairment and behavioral changes, and/or affective symptoms and the disease process as a whole [7]. The majority of studies tend to consider awareness in a global sense, although recent research has emphasized the need to relate it to specific domains [8]. Objects of awareness, like memory functioning or financial skills, among many others, can be grouped into a range of domains including cognition, functional ability, emotional and social functioning, and behavioral difficulties [6, 9]. Most studies have focused primarily on awareness of cognitive functioning impairments [10, 11] and only few studies assessed other domains such as awareness of deficits in activities of daily living [12], emotional and social functioning [13] or behavioral difficulties [8]. People with dementia may recognize some cognitive deficits, but that does not always imply an awareness of changes in other domains [2, 14].

Starkstein et al. [15] were one of the first to report the multidimensional aspect of awareness by studying two domains: awareness of cognitive deficits and awareness of behavioral problems. While lack of awareness of cognitive deficits was related to the severity of intellectual impairment, and the presence of a delusional apathetic mood, the lack of awareness of behavioral problems appeared as part of a disinhibition syndrome. Interestingly, each of these domains showed a correlation with different clinical, cognitive, and psychiatric aspects, pointing out that awareness domains may have different mechanisms of functioning [15].

The deficit in awareness as a whole has been related to global cognitive impairment [16], memory function impairment [4], neuropsychiatric symptoms [17], depression [18], worse perceived quality of life (QoL) [17], and caregiver burden [13]. However, when considering awareness domains, there may be several differences in their pattern of functioning. Lacerda et al. [11], in a systematic review, concluded that cognitive impairments and the severity of dementia do not have a direct relationship with awareness, which can worsen or remain stable in people with Alzheimer’s disease (AD). Even considering the close association between awareness and memory impairments, a relationship between awareness and attention, language, and executive functioning has also been observed [19]. Besides, cross-sectional research found that impaired awareness of cognitive functioning and health condition demonstrated an association with reduced awareness of impairment on functional activities, and also with the age of the person with dementia and the perceived caregiver’s burden [20].

The socio-emotional domain of awareness in-volves the perception of people with dementia regarding their behavior, personality, and perceptions of themselves and others [6]. Impaired awareness of socio-emotional functioning has been related to lower cognitive performance, which suggests a rela-tionship between the severity of dementia and the degree of awareness in this domain [6]. Another study found a relationship between self-reported QoL and level of awareness in three areas of social-emotional functioning (emotional recognition and empathy, social relationships, and pro-social behavior) [13]. These results showed the importance of investigating not only the cognitive domain, but other domains of awareness which may influence the functioning of people with dementia, such as functional activity.

The functional activity domain is related to the ability to acknowledge deficits in the activities of daily living. The literature shows that the degree of complexity of different types of functional activities is important to the ability to recognize deficits in performance among people with dementia [21]. From early stages of dementia, cognitive deficits may be associated with impairment on activities of daily living [22]; people with dementia can identify changes in their routine, but usually underestimate their severity, which shows impairment in awareness of the functioning of activities of daily living [23]. In addition, increased difficulties in activities of daily living appear to be related to impaired awareness and becomes worse when associated with depression [12, 23].Thus, although one domain can influence another, the factors related to each domain of awareness may vary [14, 20]. This leads to the question of whether early age would have a different impact on awareness and its domains on this specific group of people with dementia.

Young onset dementia (YOD) is a diagnosis given when the neurocognitive process sets in before 65 years of age [24]. AD is the most common type of dementia associated with YOD. Those people are more likely to initially present deficits in attention, visual-spatial function, praxis, and language, whereas in late-onset AD, the most prominent loss occurs in short-term memory [25]. Another characteristic of YOD is a faster course of the disease [26]. The YOD dementia process poses specific challenges related to financial issues, work and social demands, marriage, and parenthood, including losses and shifting roles, care responsibilities, as well as prospects for the future [27]. Those challenges might account for the difference in awareness between YOD and late onset dementia (LOD) [28, 29]. Preserved awareness in people with YOD has been reported and might also be partially explained by their atypical cognitive profile, since they often present more preserved memory at the time of diagnosis as opposed to those with LOD [28, 30]. However, there is a lack of research investigating whether there are differences in the domains of awareness according to the age at onset of dementia.

In this context, the present work aims to assess whether there are differences in awareness domains between people with YOD and LOD. We also aim to examine associations between awareness and its domains (cognitive functioning and health condition, functional activity impairments, emotional state, social functioning, and relationships) with cognition, functionality, neuropsychiatric symptoms, social and emotional functioning, and QoL. Considering our previous study [29], we hypothesize that people with YOD are significantly more aware in all domains of awareness than people with LOD, even though the first group may have a greater impairment in cognition.

MATERIALS AND METHODS

Design

Cross-sectional design.

Participants

The participants were 136 people with dementia (YOD = 50 and LOD = 86) and their caregivers recruited from an AD outpatient unit in Rio de Janeiro. They were consecutively selected according to the physicians’ referrals from January 2016 to January 2019. The participants were diagnosed with possible or probable AD or vascular dementia according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) [24], since these are the most common causes of dementia and have a similar clinical presentation. A psychiatrist made the diagnosis using clinical interviews with people with dementia and their caregivers as well as cognitive screening tests, laboratory tests, and imaging.

Only individuals with mild and moderate dementia according to the Clinical Dementia Rating (CDR) [31, 32], and with scores between 11–26 on the Mini-Mental State Examination (MMSE) [33, 34] were included in the study. We excluded people with a history of psychiatric or other neurological disorders as well as those with other causes of dementia, such as frontotemporal dementia, aphasia, head trauma, epilepsy, or alcohol and drug abuse, as defined by DSM–V.

The primary family caregiver was defined as the person most responsible for the care of the person with dementia. This person had to care for the patient at least once to twice a week and had to be able to express judgments on actual daily life behaviors and impairments. Caregivers with a reported history of psychiatric or cognitive disorders were excluded. All caregivers had been previously informed of the AD or vascular dementia diagnosis by the psychiatrist. The people with dementia completed assessments about QoL, cognition, social and emotional functioning, and their awareness. The caregivers provided information about the person with dementia (including demographics, the ability to perform activities daily living, awareness, social and emotional functioning, and neuropsychiatric symptoms).

The study was approved by the Ethics in Research Committee of the Institute of Psychiatry (IPUB) of the Universidade Federal do Rio de Janeiro (UFRJ).

All people with dementia and their caregivers signed the informed consent term.

Instruments

Awareness. The Assessment Scale of Psychosocial Impact of the Diagnosis of Dementia (ASPIDD) is a multidimensional 30-question scale based on dyad reports. It evaluates awareness of disease through scoring of discrepant responses across the following domains: awareness of cognitive functioning and health condition, functional activity impairments, emotional state, social functioning, and relationships. The awareness score is based on the degree of discrepancy between the person with dementia and the caregiver’s dyad responses, with one point being scored for each discrepant response. The ratings of awareness total score range from preserved (0–4), mildly impaired (5–11), moderately impaired (12–17), to absent (over 18). The scores for domains are given as follows: Awareness of cognitive functioning and health condition (0–7), emotional state (0–5), social functioning and relationships (0–7), and functional activity impairments (0–11) [9].

Dementia severity. The severity of dementia was measured with the clinical dementia rating scale (CDR), with stages ranging from 0 (no dementia) to 3 (severe dementia) according to cognitive, behavioral and activities of daily living impairment [31, 32]. A higher score denotes more severe dementia.

Cognition. Cognitive level was measured using the MMSE which includes tasks of orientation, registration, short-term memory, language use, comprehension, and basic motor skills. The total score ranges from 0 to 30. Lower scores indicate more impaired cognition [33, 34].

Functionality. The Pfeffer Functional Activities Questionnaire (PFAQ) is a caregiver-reported inventory that evaluates activities of daily living. The ratings for each item range from normal (0) to dependent (3), with a total of 30 points. Higher scores indicate worse functional status [35, 36].

Neuropsychiatric symptoms. Neuropsychiatric In-ventory (NPI) assesses the presence of delusions, hallucinations, dysphoria, anxiety, agitation/aggres-sion, euphoria, disinhibition, irritability/lability, apathy, aberrant motor activity, night-time behavior disturbances, and appetite and eating abnormalities. Each item is rated concerning their frequency, one (absent) to four (frequently), and intensity, one (mild) to three (severe). The total score can range from zero to 144 points. A higher score means a higher presence of neuropsychiatric symptoms [37, 38].

Social and emotional functioning. Social and Emotional Questionnaire (SEQ) consists of 30 items distributed in 5 aspects: recognition of emotion, empathy, social conformity, antisocial behavior, and sociability. The ratings are scored on a 5-point Likert scale, from strongly disagree (1) to strongly agree (5). The people with dementia and the caregiver versions are essentially identical. Both participants and informants were asked to answer the questionnaire individually. This ensured anonymity of responses as well as preventing conferring over answers between participants and informants. The person with dementia rated his/her socioemotional functioning with regards to the ability to recognize emotions, their behavior in social situations, and the extent of their empathetic reactions. Caregivers also answered about the current emotional and social functioning of their person with dementia. The score is based on the degree of the discrepancy between people with dementia and caregivers’ ratings. Discrepancy scores close to 0 indicate good agreement between them. Positive and negative discrepancy scores are interpreted as indicating lower awareness [39, 40].

Quality of life. We used the Quality of Life in Alzheimer’s Disease scale (QoL-AD). This questionnaire was developed specifically to assess QoL in dementia. The QoL-AD includes 13 domains: physical health, energy, mood, living situation, memory, family, marriage, friends, chores, fun, money, self, and life as a whole. The 13 domains are rated as poor (1), fair (2), good (3), or excellent (4), and the total score ranges from 13 to 52. Higher scores mean better self-reported QoL [41, 42].

Statistical analyses

Kolmogorov–Smirnov and Levene tests were used to verify the normal and homoscedasticity distribution, respectively. Parametric variables were des-cribed by their mean and standard deviations (SD), and the non-parametric variables by their median, minimum and maximum or frequency and percentages for categorical variables. Chi-square and Mann-Whitney U tests were used for non-parametric and Independent T-tests for parametric comparation between YOD and LOD groups. Also, Kruskal-Wallis and ANOVA One Way tests were used for non-parametric and parametric comparison between YOD and LOD groups separated by CDR classification. Finally, multivariate linear regressions with the stepwise method were elaborated using the ASPIDD total scores and its domains as dependent variables, in order to identify the association with the independent variables (CDR, MEEM, NPI, SEQ, QOL, and PFEFFER). Regression models were performed separately for YOD and LOD groups and the best models were selected according to highest explained variance of the R square (R²) and the variance inflation factor (VIF) close to 1, for the collinearity in each independent variable. Statistical analyses were performed using SPSS® software, version 26.0 (IBM Corporation, NY, USA), and the level of significance adopted was p≤0.05.

RESULTS

Sociodemographic characteristics

People with YOD

The individuals with YOD (N = 50) had a median age of disease onset of 59 (41–64), and a median duration of disease of 5 years (0–13). Almost half of the group with YOD were in the mild stage of the disease (CDR 1) (48%, N = 24). Most people in the YOD sample had AD (88%, N = 44). They had a median of 11 years (2–16) of education, and 52%were male (N = 26).

People with LOD

The individuals with LOD (N = 86) had a median age of disease onset of 75 (65–90), and a median duration of disease of 4 years (1–16). Most people with LOD were in a mild stage of the disease (CDR1; 59.3%, N = 51) and the vast majority had AD (88.4%, N = 76). They had a median educational level of 7.5 years (2–20), and 30, 2% were male (N = 26).

As expected, a significant difference was found in the age of disease onset between the two groups, people with YOD were significantly younger than people with LOD (p < 0.001). The YOD group also presented higher education level than the LOD group (p = 0.001).

The comparison between people with YOD and LOD characteristics are presented in Table 1.

Table 1

People with dementia’s sociodemographic characteristics according to disease onset

Variable	PwYOD (N = 50)	PwLOD (N = 86)	χ²	p
Male N (%)	26 (52)	26 (30.2)	6,344	0.012^**
Female N (%)	24 (48)	60 (69.8)
Age of onset (y)	59 (41–64)	75 (65–90)	4,300	< 0.001^***
Years of disease (y)	5 (0–13)	4 (1–16)	1,970.5	0.43
Mild stage N (%)	24 (48)	51 (59.3)	1,633	0.20
Moderate stage N (%)	26 (52)	35 (40.7)
DA N (%)	44 (88)	76 (88.4)	136,000	< 0.001^***
DV N (%)	6 (12)	10 (11.6)
Schooling (y)	11 (2–16)	7.5 (2–20)	1,418	0.001^***

PwYOD, people with young onset dementia; PwLOD, people with late onset dementia; ^***p < 0.001; ^**p < 0.01; ^*p < 0.05.

Table 3

Regression model of factors related to awareness of disease and its domains among people with YOD

	B	IC95%	R²	Significance
ASPIDD total score
PFAQ	0.451 (p < 0.001^***)	0.299; 0.602	0.433	< 0.001^***
ASPIDD Cognitive functioning and health condition
PFAQ	0.092 (p = 0.003^**)	0.033; 0.152	0.171	0.003^**
ASPIDD Functional activity impairments
PFAQ	0.257 (p < 0.001^***)	0.171; 0.343	0.433	< 0.001^***
ASPIDD Emotional State
PFAQ	0.068 (p = 0.003^**)	0.025; 0.112	0.174	0.003^**

ASPIDD: Assessment Scale of Psychosocial Impact of the Diagnosis of Dementia; PFAQ, Pfeffer Functional Activities Questionnaire; B, Linear coefficient; R2, coefficient of determination. ^***p < 0.001; ^**p < 0.01; ^*p < 0.05.

Clinical characteristics of people with YOD and LOD

People with YOD were more severely cognitive impaired, according to MMSE (p < 0.001); they also had a worse level of functionality, being more dependent on activities of daily living, even in the mild stage of disease (p < 0.001) and had more neuropsychiatric symptoms (p = 0.015) than people with LOD. Regarding awareness and its domains, people with YOD were more aware of disease (total score) (p = 0.012), of their cognitive functioning and health condition (p < 0.001), and of their functional activity impairments (p = 0.033) than people with LOD, even in the moderate stage of the disease. We did not find any other significant differences between groups on the other domains of awareness and clinical variables. The differences between the clinical characteristics of both groups are summarized in Table 2.

Table 2

People with dementia’s clinical characteristics according to disease onset and disease stage

Variable	YOD CDR1 (N = 24)	YOD CDR2 (N = 26)	LOD CDR1 (N = 51)	LOD CDR2 (N = 35)	χ²	p
ASPIDD Total score (score)	7 (0–22)	8.5 (1–19)	8 (0–17)	12 (4–20)	11.002	0.012^*
ASPIDD cognitive functioning and health condition (score)	1 (0–6)	2.5 (0–6)	2 (0–6)	4 (0–7)	22.297	< 0.001^***
ASPIDD functional activity impairments (score)	2 (0–11)	5 (0–11)	3 (0–9)	5 (0–10)	8.748	0.033^*
ASPIDD emotional state (score)	1 (0–4)	1 (0–5)	1 (0–5)	1 (0–5)	1.202	0.753
ASPIDD social functioning and relationships (score)	1 (0–5)	1 (0–3)	1 (0–5)	1 (0–4)	1.552	0.670
MMSE (score)	21 (12–26)	14 (7–19)	22 (16–27)	15 (11–19)	88.942	< 0.001^***
NPI (score)	12 (1–61)	21 (0–77)	9 (0–48)	13 (2–91)	10.434	0.015^*
SEQ (score)	0.11 (–0.14; 0.78)	0.01 (–0.13; 2.00)	0.04 (–0.25; 1.00)	0.03 (–0.38; 0.35)	3.918	0.270
QoL-AD (SD)	33.69 (6.28)	34.34 (6.43)	33.13 (5.11)	33.28 (5.23)	0.287	0.835
PFAQ (score)	17 (3–30)	22 (3–30)	11 (1–30)	25 (8–30)	25.652	< 0.001^***

PwYOD, people with young onset dementia; PwLOD, people with late onset dementia; SD, standard deviation; ASPIDD, Assessment Scale of Psychosocial Impact of the Diagnosis of Dementia; MMSE, Mini-Mental State Examination; NPI, Neuropsychiatric Inventory; SEQ, Social and Emotional Questionnaire; QoL-AD, Quality of Life in Alzheimer’s disease-score patient about yourself; PFAQ, Pfeffer Functional Activities Questionnaire. ^***p < 0.001; ^**p < 0.01; ^*p < 0.05.

Multivariate analyses

Multivariate linear regressions examined the relationship between awareness total score and its domains and all clinical variables in both YOD and LOD groups.

People with YOD

A lower total score on awareness was related to lower levels of functionality (p < 0.001). The final model explained 43% of the observed variance (p < 0.001).

Lower levels of awareness of cognitive functioning and health condition were related to lower levels of functionality (p = 0.003). The final model explained 17% of the observed variance (p = 0.003).

Lower levels of awareness of functional activity impairments were related to lower levels of functionality (p < 0.001). The final model explained 43% of the observed variance (p < 0.001).

Lower levels of awareness of emotional state were related to lower levels of functionality (p = 0.003). The final model explained 17% of the observed variance (p = 0.003).

There was no relationship with any of the clinical variables for social functioning and relationships domain.

People with LOD

Lower total scores on awareness were related to lower levels of functionality (p = 0.002), better self-reported QoL (p < 0.001), higher levels of neuropsy-chiatric symptoms (p = 0.008). and worse cognitive performance (p = 0.029). The final model explained 48% of the observed variance (p < 0.001).

Lower levels of awareness of cognitive functioning and health condition were related to lower levels of functionality (p = 0.001), better self-reported QoL (p < 0.001), and higher levels of neuropsychiatric symptoms (p = 0.024). The final model explained 35% of the observed variance (p < 0.001).

Lower levels of awareness of functional activity impairments were related to lower levels of functionality (p < 0.001) and better self-reported QoL (p < 0.001). The final model explained 36% of the observed variance (p < 0.001).

Lower levels of awareness of emotional state were related to better self-reported QoL (p = 0.010) and lower levels of functionality (p = 0.031). The final model explained 13% of the observed variance (p = 0.003).

Lower levels of awareness of social functioning and relationships were related to higher levels of neuropsychiatric symptoms (p < 0.001). The final model explained 14% of the observed variance (p < 0.001).

Table 4

Regression model of factors related to awareness of disease and its domains among people with LOD

	B	IC95%	R²	Significance
ASPIDD total score
MMSE	0.247 (p = 0.029^*)	–0.469; –0.025	0.476	< 0.001^***
PFAQ	0.171 (p = 0.002^**)	0.063; 0.280	0.476
NPI	0.064 (p = 0.008^**)	0.017; 0.112	0.476
QoL-AD	0.409 (p < 0.001^***)	0.251; 0.567	0.476
ASPIDD Cognitive Functioning and health condition
PFAQ	0.056 (p = 0.001^**)	0.023; 0.090	0.351	< 0.001^***
NPI	0.019 (p = 0.024^*)	0.003; 0.036	0.351
QoL-AD	0.131 (p < 0.001^***)	0.075; 0.187	0.351
ASPIDD Functional activity Impairments
PFAQ	0.131 (p < 0.001^***)	0.078; 0.184	0.358	< 0.001^***
QoL-AD	0.195 (p < 0.001^***)	0.104; 0.286	0.358
ASPIDD Emotional State
QoL-AD	0.081 (p = 0.010^**)	0.020; 0.143	0.133	0.003^**
PFAQ	0.040 (p = 0.031^*)	0.004; 0.075	0.133
ASPIDD Social Functioning and relationships
NPI	0.026 (p < 0.001^***)	0.012;0.040	0.138	< 0.001^***

ASPIDD: Assessment Scale of Psychosocial Impact of the Diagnosis of Dementia; MMSE, Mini-Mental State Examination; PFAQ, Pfeffer Functional Activities Questionnaire; QoL-AD, Quality of Life in Alzheimer’s disease-patient’s score about yourself; NPI, Neuropsychiatric Inventory; B, Linear coefficient; R2, coefficient of determination; ^***p < 0.001; ^**p < 0.01; ^*p < 0.05.

DISCUSSION

To the best of our knowledge, this is the first study to investigate whether there are differences in awareness and its domains, namely, cognitive functioning and health condition, functional activity impairments, emotional state, social functioning, and relationships between people with YOD and LOD. Also, this study assessed the relationship between clinical factors of the disease and awareness and its domains among people with YOD and LOD.

Differences in clinical aspects and awareness discrepancy in people with YOD and LOD

We had hypothesized that people with YOD would have significantly higher awareness in all awareness domains studied compared to people with LOD. Surprisingly, we found no significant differences between the groups concerning the domains related to the emotional state, and social functioning and relationships. We observed that both groups of people with dementia had a mildly impaired awareness in the domains of social functioning and relationships and emotional state.

Our major finding is related to the differences in awareness between both groups, even when these differences were analyzed according to the severity of the disease. Compared to people with LOD, we found higher levels of awareness total score, awareness of cognitive functioning and health condition, and awareness of functional activity impairments domains in people with YOD, even in the moderate stage of the disease. Also, people with YOD had greater levels of awareness compared to the LOD group, even though they were more cognitively impaired and had a worse level of functionality, being more dependent on activities of daily living. This finding is consistent with previous studies that have found that younger age of disease onset is related to greater awareness [8 , 43]. Studies on demographic characteristics related to awareness have shown that older age is associated with lower levels of awareness of AD related deficits [43]. For example, a previous study [14] found that age was related to awareness of cognitive functioning and health condition in people with moderate AD. It is possible that because people with YOD are immersed in a more demanding world than the older group—they may still be in the labor market, have a more intense social life, and, often, even have children who are still dependent—they are more stimulated despite their cognitive difficulties. It is also possible that people with YOD are more confronted with their difficulties because of the world demands [28, 29]. Compared to the LOD group, those findings might also be explained by the atypical cognitive profile of people with YOD who often have initially more preserved memory but a greater loss of motor skills, executive functions, visuospatial functioning, attention, or language [25]. Besides, people with LOD tend to attribute their forgetfulness to be a normal characteristic of old age and not related to an illness [29].

Our study results also revealed that people with YOD have more neuropsychiatric symptoms (NPI) compared to people with LOD. However, there was no significant difference between groups in social functioning and relationships or emotional state domains of awareness. Previous studies have reported that impaired awareness of socio-emotional functioning is related to lower cognitive performance [6] and to the presence and severity of behavioral and psychiatric disorders in people with AD [13, 44]. Some reports that suggest that more preserved awareness has been associated with depressive symptoms and anxiety [8, 28]. Other studies report the relationship between impaired awareness and disinhibition, irritability, anxiety, agitation, and aberrant motor behavior [8, 17]. It is expected that people with more neuropsychiatric symptoms will have greater difficulty in socio-emotional functioning. Differences in neuropsychiatric symptoms can be the result of greater demands for expected functional and social engagement from younger people than from someone older, likely already retired, and often with fewer social assignments.

Considering the impact of neuropsychiatric symptoms on awareness, we may suppose that the YOD group had better awareness, despite their higher cog-nitive, functional and behavioral difficulties. However, this supposition needs further research including which neuropsychiatric symptoms are recurrent in both groups.

Factors associated with awareness and its domains in people with YOD and LOD

As previously discussed and demonstrated in the present work, awareness is related to the impairment of particular abilities and should not be isolated from its domains and the objects linked to each domain [6]. In turn, different domains define several kinds of judgments and are qualitatively distinct [12].

Impaired functionality was related to deficits in awareness (total score), as well as awareness of cognitive functioning and health condition, awareness of functional activity impairments and awareness of emotional state in both groups of people with dementia. Those findings are in line with previous studies and suggest that abilities of daily functioning might have an intrinsic relationship with awareness [14, 29]. Therefore, people with dementia may present reduced awareness of their daily problems or impairments because they tend to overestimate their performance in functional activities; a behavior that may be attributed to the failure in updating the mental representations of the functional activity [2 , 20]. People with dementia may experience a decline in specific mnemonic processes leading to a loss of personal knowledge and awareness of functional ability [21]. This should be considered as a special case of personal trait judgment that concerns personal efficacy.

Functionality was the only variable related to awareness (total score) and all domains, except the emotional state domain for the YOD group. Thus, the level of functionality seems to have a greater impact on awareness in the YOD group. Maki et al. [16] found a lack of awareness of instrumental activities of daily living (doing home activities, practicing favorite’s hobbies, and handling money), and presumed that awareness of activities that requires executive functions might deteriorate before awareness of memory or orientation. These aspects are in accordance with the clinical features of YOD and with our finding that people in the mild stage of YOD had a worse level of functionality compared to the LOD group.

In this study, QoL is a variable related to four of the five dependent variables in the LOD group: awareness total score, awareness of cognitive functioning and health condition, awareness of functional activity impairments and awareness of emotional state. QoL involves a subjective perception of physical, social and psychological variables [41]. Studies have shown that people with dementia tend to rate their QoL better when they are unaware of their deficits [44, 45]. A previous study by Lacerda et al. [14], also found a relationship between QoL and awareness (total score) and awareness of their cognitive functioning and health condition in people with a mild stage of dementia. We may suppose that absence of QoL as a related variable in the YOD group may be due to their level of cognitive functioning and disease severity as they were more cognitively impaired and in the moderate stage of the disease when compared to the LOD group. People with mild dementia tend to be more active, so their cognitive impairments may adversely affect their QoL since dementia involves loss of social roles and responsibilities [45]. We may assume that the impairments and changes caused by the disease may also impact their emotional state, decreasing their perceptions about their QoL. But thinking about the specifics of YOD, as already reported, it is surprising that this variable did not appear in relation to any of the domains among the YOD group.

Additionally, in the LOD group, impaired awareness of social functioning and relationships was related to the presence of neuropsychiatric symptoms. Neuropsychiatric symptoms, such as agitation, apathy, and depression, have important clinical and care management consequences for people with dementia and their caregivers [17 , 44]. Impaired awareness of socio-emotional skills has been associated with the presence and severity of behavioral and psychiatric disorders in people with AD [13]. Even though the YOD group presented higher levels of neuropsychiatric symptoms, this variable did not appear to be associated to any awareness domains, not even to awareness of social functioning and relationships domain. In the LOD group, the neuropsychiatric symptoms were related to awareness (total score) and the awareness of cognitive functioning and health condition domain. Toyota et al. [46] compared neuropsychiatric symptoms between people with YOD and LOD and observed a greater presence of delusions, hallucinations, agitation, disinhibition, and aberrant motor behavior in the LOD group. Thus, a possible explanation for a broader influence of neuropsychiatric symptoms in the LOD group may be related to the relationship between impaired awareness and disinhibition, irritability, anxiety, agitation, and aberrant motor behavior [28, 30]. However, we did not evaluate the type of neuropsychiatric symptoms between groups, which would have allowed a better understanding of the relationship between awareness and this kind of symptoms according to the age of dementia onset.

This study has some limitations. We had a relatively small sample size, which might make the analyses underpowered. The sample was collected at an outpatient center for dementia, so they received health services and varying levels of information regarding their condition, which makes it difficult for the results to be generalized to other less supported individuals with dementia. Also, as the cross-sectional study limits the inference of causality in-between studied variables.

Our findings show that impairment in awareness is influenced by different variables according to the age of dementia onset. Also, people with YOD had a more preserved awareness total score, a more preserved awareness about their cognitive functioning and health condition and about their functional activity impairments compared to the LOD group, even though the first group was more cognitively impaired and more dependent on activities of daily living. Our study shows that level of functionality is crucial to recognize deficits of people with YOD. Conversely, the level of neuropsychiatric symptoms and self-reported QoL has a greater influence on awareness for people with LOD. We should move on to further studies with a larger sample and to deepen understanding, engage in longitudinal research. Differences in awareness and its domains in YOD and LOD is a field still under development and, therefore, fertile for the studies that may be particularly relevant to a clinical setting, enabling interventions focused on increasing the QoL for those populations and thus, meeting their specific needs and demands as well as those of their families.

Footnotes

ACKNOWLEDGMENTS

We are grateful to Prof. Linda Clare for providing helpful comments. We would like to thank Dr Anita Sohn McCormick from the Research and Editing Consulting Program (RECP) for the careful revision of the manuscript and editing for English language. Marcia Cristina Nascimento Dourado is a research funded by National Council for Scientific and Technological Development –CNPq.

Authors’ disclosures available online ().

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