Highlights
- •Adults with DM1 childhood phenotype are frequently dependent in their IADL.
- •Financial management was one of the most difficult IADL to accomplish.
- •Dependence in IADL was more frequently observed in participants with apathy.
- •84.8% were dependent or needed verbal assistance to formulate a goal.
Abstract
Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy among adults. This cross-sectional study documents the level of independence in the instrumental activities of daily living (IADL) and explores the impact of executive functions and apathy on IADL accomplishment level among adults with the childhood phenotype of DM1. IADL accomplishment level was assessed with the Independent Living Scale (ILS) and the Activities of Daily Living Profile (ADL Profile). The later considered four operations related to executive functions: formulating a goal, planning, carrying out the task and goal attainment. Thirty-three individuals (19 females; mean age 39y, standard deviation 10y 6mo; range 23–57y) were recruited. According to the ILS total score, half of the participants were categorised as dependent. In financial management, no participant obtained the minimal score for independence. In the ADL Profile, higher dependence levels were frequent in IADL. Formulating a goal was the most difficult operation. Dependence level was more frequent in participants with apathy. Adults with the childhood phenotype exhibit significant difficulties in IADL accomplishment, especially considering their age. High levels of dependency observed with both outcome measures highlight their need for services to achieve optimal living conditions.
Keywords
1. Introduction
Myotonic dystrophy type 1 (DM1) is a multisystemic neuromuscular disorder with muscular, ocular, cardiac, endocrine, gastrointestinal and central nervous impairments [
[1]
]. It is an autosomal dominant disorder caused by a cytosine-thymine-guanine (CTG) trinucleotide repeat expansion in the DMPK gene [[2]
]. The inheritance pattern is characterised by anticipation, i.e., increasing disease severity and decreasing age of onset in successive generations [[3]
]. Five phenotypes are currently recognised and based on age at onset and symptoms severity: congenital, childhood, juvenile, adult and late-onset [[4]
,[5]
. The clinical presentation is different in terms of presenting symptoms and progression over time [[6]
]. This variability implies very distinct prognosis in terms of their ability to gain or maintain independent living, which in turn modulates quality of life of affected individuals, and the burden experienced by parents or caregivers [[7]
].Among the different phenotypes, the childhood one has been scarcely described. According to the original diagnosis criteria from Koch, DM1 in children is characterised by facial weakness, dysarthria, hand muscle myotonia and delayed motor development, occurring between 1 and 10 years old with absence of neonatal problems [
[3]
]. However, more recent descriptions have included poor school performance and gastro-intestinal problems as potential presenting symptoms as well. Muscular impairment is not a main feature during childhood as it remains mild and does not lead to major disabilities during childhood or adolescence [[5]
,[8]
. However, children present with lower IQ levels and cognitive impairments, such as speech and language delay, learning disability and lower performance in relation to adaptive behaviours, socialization and communication [[5]
,[9]
,[10]
, which might have a greater influence on daily functioning especially in more complex activities [[11]
].Both motor and neuropsychological impairments lead to participation restrictions for people living with DM1 [
[12]
,[13]
, compromising independent living in several cases. Accomplishment of activities of daily living (ADL) is essential to achieve autonomous living. It includes basic ADL (BADL) which are simple self-care tasks aimed to answer basic physical needs (i.e., brushing teeth), whereas instrumental ADL (IADL) are more complex activities required to participate in domestic and community life. The American Occupational Therapy Association recognises 12 IADL including 1) driving and community mobility; 2) financial management; 3) health management and maintenance; 4) home establishment and management; 5) meal preparation and cleanup and 6) safety and emergency maintenance. Only two studies have partially documented IADL in adults with the childhood phenotype and highlighted major issues. Firstly, a retrospective chart review reported that 51% of adults still lived with their parents or in foster homes [[14]
]. Ninety-one percent of adults had difficulties in housing activities, and financial responsibilities were an issue for at least 21% of them [[14]
]. Secondly, a transversal exploratory study has found that 8/11 participants were dependent to accomplish several IADL, including money and home management [[15]
], but the small sample size limited the generalization of the results. The present lack of evidence-based data regarding their potential for independent living causes important challenges for patients, relatives and clinicians.Indeed, Ekström et al. suggested that in everyday life, individuals with congenital or childhood DM1 are more affected by central nervous system-related symptoms, such as cognitive deficits and neuropsychiatric problems, rather than by their neuromuscular symptoms [
[16]
]. Specifically in the childhood phenotype, Eriksson et al. assessed 31 children and young adults, and observed deficits in motor and process skills that interfered with ADL performance (including BADL and IADL), compared to normative data [[17]
]. They also noted that processing skills were more affected than motor skills [[17]
]. Processing skills relate to executive functions and are particularly involved in the accomplishment of IADL because of their higher complexity. Furthermore, studies have shown that a high percentage of DM1 individuals were apathetic [[18]
] which could influence the volitional aspect of the accomplishment of an activity.Therefore, the objectives were, among adults with the childhood phenotype of DM1, to 1) document the IADL accomplishment level; and to 2) explore the impact of executive functions and apathy on IADL accomplishment.
2. Methods
2.1 Participants
To be eligible in the study, participants needed to be 1) between 18 and 59 years of age; 2) with a diagnosis of DM1 confirmed by DNA analysis; 3) classified as childhood phenotype [
[19]
]; 4) be able to provide informed consent or having the consent from a legal guardian and being willing to participate. Exclusion criterion was to present a medical condition that could have an impact on the ability to perform IADL. The Ethics Committee of the CIUSSS of Saguenay–Lac-Saint-Jean approved the study. The individuals participated voluntarily after written informed consent was obtained.2.2 Data collection and outcome measures
In this cross-sectional study, a trained occupational therapist assessed participants at their home over two half-day sessions. Following a literature review, no outcome measure that assessed all IADL was identified. Two outcome measures that assess different IADL using different assessment modalities were chosen.
The Independent Living Scale (ILS: French version) requires participants to do problem solving, to demonstrate knowledge or to perform a task to allow a direct, objective evaluation of daily life functioning. It comprises 70 items with five subscales: 1) Memory/Orientation, 2) Social adjustment, 3) Money management, 4) Home & transportation and 5) Health & safety [
[15]
,[20]
. These subscale scores are added to obtain a total score reflecting the participant's ability to function independently. The last three categories are considered IADL. Raw scores are derived into standard scores, which ranged from 20 to 63 for subscales and from 55 to 121 for the total score, where a higher score indicates better capacities. It presents good inter-rater reliability (K = 0.99) and good test-retest reliability (r = 0.80) with the elderly [[20]
].At the second visit, the Activities of Daily Living Profile (ADL Profile) was administered. It is an observational measure of independence that considers the impact of executive functions on everyday activities by documenting operations, which are the smallest functional units of the accomplishment of an activity [
[21]
]. By observing the participant accomplishing activities, the evaluator notes observable behaviours and verbalisations that inform the evaluator of how the participant is thinking while accomplishing the task. These observations are then grouped into four operations (formulating a goal, planning, carrying out the task, and verifying attainment of the goal) to identify specific areas of difficulties during activity accomplishment. The scoring procedure considers the degree of independence of the participant when she/he accomplishes the different tasks (task score) and the way she/he carries them out (operations score). The scoring scales allow the evaluator to determine the presence or absence of difficulties and the type of assistance required from another person to complete each operation (verbal, physical, or both). Each observed operation and each task are scored according to a four-point ordinal scale of independence (3: independence; 2: independence with difficulty; 1: verbal, physical, or verbal and physical assistance required; and 0: inability to complete the task despite the assistance offered by the evaluator). The lowest of these operation scores is used to determine the task score. Bottari et al. determined that a subset of 6 tasks (instead of all 17 tasks available in the instrument) can be used for a less burdening assessment, if the selection of items is not limited to easy or complex tasks and items are sampled throughout all the three ADL environments (personal, home and community) [[21]
]. For this study, the following six tasks were chosen by the research team: 1) Grooming; 2) Putting on clothes and shoes; 3) Doing daily house cleaning; 4) Preparing a hot meal; 5) Telephoning for information and 6) Making a budget. The ADL Profile was administered by a trained occupational therapist during a half-day period. Breaks were suggested to participants. According to the American Occupational Therapy Association. The first two tasks are BADL and the others are IADL. Tool development and interrater reliability with a severe traumatic brain injury population were previously described [[22]
]. Interrater reliability (Kappa) ranged between 0.23 (acceptable reliability) and 0.72 (substantial reliability) [[22]
].It is important to note that the two outcome measures used for IADL accomplishment (ILS and ADL Profile) were complementary. The ILS is a written questionnaire administered by the occupational therapist. It is used as a screening tool to obtain a quick picture of potential red flags related to the ability to maintain safe independent living, whereas the ADL Profile is administered with the assessor observing real-life situations, which is more related to a clinical assessment of an occupational therapist.
Finally, presence of apathy was assessed with the clinician version of the Apathy Evaluation Scale (AES-C) [
[23]
]. Items address the affective, behavioural, and cognitive domains of apathy and are rated on a 4-point scale with a total score ranging from 18 to 72 points. A cut-off score of 39 or higher indicates clinical apathy, based on elderly population [[24]
]. Some psychometric properties of the AES have been established in the DM1 population [[25]
].2.3 Data analysis
Descriptive statistics are used for sociodemographic data (mean scores and standard deviation). Frequencies were used to describe levels of independence among our participants. Given the sample size and the objectives, we used cut-off scores to categorize participants according to level of IADL accomplishment, reflecting their potential for independent living. Standardised cut-off scores are available in the ILS procedures and were used to classify participants in three categories for each subscale and total score. For the subscales, the three categories were independent (activity accomplished ≥ 50), semi-independent (40–49) and dependent (≤ 39). For the total score, the classification was independent (activity accomplished ≥ 100); semi-independent (85–99); and dependent (≤ 84), with a maximum score of 121. The standardization process was made from a sample of 590 healthy older adults (age ≥ 65 years old) in the United States population, depending on their living status [
[20]
]. The AES-C was used to divide our sample in two subgroups according to presence of apathy, to observe levels of independence in each subgroup. There is no normative data available for the ADL Profile. Fisher's exact test was used to analyze differences between groups and was conducted at a 5% significance level. Data were analysed using IBM SPSS Statistics for Windows, Version 25.0 (Armonk, NY: IBM Corp).3. Results
3.1 Characteristics
Demographic and personal characteristics are presented in Table 1. A sample of 33 individuals was recruited from a subset of 65 adults with the childhood phenotype from the registry at the Neuromuscular Clinic of the Centre intégré universitaire de santé et de services sociaux du Saguenay–Lac-Saint-Jean (CIUSSS-SLSJ) (Quebec, Canada) which is part of the DM-Scope registry [
MIRS = Muscular Impairment Rating Scale.
[26]
]. Fifty persons were contacted from the registry and 36 accepted. One participant abandoned before the first visit due to lack of time and two because of the COVID-19 pandemic. The participants are comparable to the 14 who refused to participate in terms of age, sex and CTG repeat numbers.Table 1Characteristics of the study population.
| Characteristics | Total group (n = 33) |
|---|---|
| Age, (y) | |
| Mean (SD) | 38.9 (9.9) |
| Range | 23–57 |
| Sex, n (%) | |
| Men | 14 (42.4) |
| Women | 19 (57.6) |
| Parental transmission, n (%) | |
| Father | 13 (39.4) |
| Mother | 19 (57.6) |
| Unknown | 1 (3.0) |
| CTG repeats, number | |
| Mean (SD) | 974 (543) |
| Range | 250–2000 |
| MIRS score, n (%) | |
| 1: No muscular involvement | 1 (3.0) |
| 2: Minimal signs | 7 (21.2) |
| 3: Distal weakness | 8 (24.2) |
| 4: Mild to moderate proximal weakness | 14 (42.2) |
| 5: Severe proximal weakness | 3 (9.1) |
| Interior mobility level, n (%) | |
| No walking aid | 28 (85) |
| Cane | 1 (3) |
| Walker | 3 (9) |
| Wheelchair | 1 (3) |
| Apathy level | |
| Mean (SD) | 40.2 (9.5) |
| Range | 25–57 |
| Apathetic, n (%) | 18 (54.5) |
| Non-apathetic, n (%) | 15 (45.5) |
| Housing situation, n (%) | |
| Living with parents | 8 (24.2) |
| Living with partner | 12 (36.3) |
| Living alone | 8 (24.2) |
| Living in another situation | 5 (15.3) |
| Difficulties in school, n (%) | |
| Yes | 29 (87.9) |
| No | 4 (12.1) |
| Level of education, n (%) | |
| High school completed | 8 (24.2) |
| High school non completed | 25 (75.8) |
| Principal occupation, n (%) | |
| At work full time | 3 (9.1) |
| At work part time | 2 (6.1) |
| At school (specialized program) | 1 (3.0) |
| At school (regular program) | 1 (3.0) |
| Does not work for health reasons | 26 (78.8) |
| Level of independence perceived, n (%) | |
| Independent | 21 (63.6) |
| Needing assistance | 11 (33.3) |
| Dependent | 0 |
Our sample had a mean age of 39 years old (SD 10) and ranged from 23 to 57 years old. Fifty-seven-point-six percent were women and 19 participants exhibited maternal inheritance. Five participants lived in non-traditional living arrangements, such as with a friend and her children. Eight participants (24.2%) had completed high school and 87.9% had difficulties in school. Most participants were able to walk without aid (63.6%) and none considered themselves dependent. Finally, 54.5% of participants were apathetic.
3.2 Level of independence in IADLs accomplishment
Levels of independence for each IADL obtained with the ILS and ADL Profile are presented in Table 2. In addition, the two ADL tasks assessed in the ADL Profile are presented. In ILS, participants were mostly semi-independent or dependent. No participant was independent in financial management. In the ADL Profile, most participants required assistance to accomplish the activities, and more frequently verbal assistance. The proportion of dependent participants is higher in IADL (15.2 to 24.2%) than in BADL (9.1 to 15.2%).
Table 2ILS and ADL Profile levels of independence (n = 33).
| ADL categories | Level of independence, n (%) | |||||
|---|---|---|---|---|---|---|
| Dependence | Semi-independence | Independence | ||||
| ILS | ||||||
| Memory and orientation | 2 (6.1) | 9 (27.3) | 22 (66.7) | |||
| IADL | Financial management | 24 (72.7) | 9 (27.3) | 0 | ||
| Home management and transportation | 12 (36.4) | 12 (36.4) | 9 (27.3) | |||
| Health and security | 15 (45.5) | 7 (21.2) | 11 (33.3) | |||
| Social adjustment | 13 (39.4) | 14 (42.4) | 6 (18.2) | |||
| Total score | 17 (51.5) | 11 (33.3) | 5 (15.2) | |||
| ADL Profile | Level of independence, n (%) | |||||
| Dependence | Assistance | Independence | ||||
| Verbal | Physical | Both | ||||
| BADL | Grooming | 5 (15.2) | 15 (45.5) | 1 (3.0) | 1 (3.0) | 11 (33.3) |
| Putting on clothes and shoes | 3 (9.1) | 2 (6.1) | 0 | 2 (6.1) | 26 (78.7) | |
| IADL | Doing daily house cleaning | 5 (15.2) | 13 (39.4) | 2 (6.1) | 6 (18.2) | 10 (30.3) |
| Preparing a hot meal | 7 (21.2) | 9 (27.3) | 0 | 3 (9.1) | 14 (42.4) | |
| Telephoning for information | 8 (24.2) | 9 (27.3) | 0 | 2 (6.1) | 14 (42.5) | |
| Making a budget | 7 (21.2) | 11 (33.3) | 0 | 1 (3.0) | 14 (42.4) | |
| Total score | 13 (39.4) | 13 (39.4) | 0 | 3 (9.1) | 4 (12.1) | |
3.3 Impact of executive functions and apathy on IADL accomplishment
Table 3 presents IADL level of independence for the four operations of the ADL Profile. Formulating a goal was the most affected operation where 84.8% of the sample were either dependent or required assistance for at least one task.
Formulating a goal could not be assessed for Making a budget as the evaluator has to give instructions to the participant.
Table 3Descriptive statistics of the ADL Profile, according to operations (n = 33).
| ADL Profile | Level of independence, n (%) | ||||
|---|---|---|---|---|---|
| Dependence | Assistance | Independence | |||
| Verbal | Physical | Both | |||
| Formulating a goal | |||||
| Doing daily house cleaning | 3 (9.1) | 14 (42.4) | 16 (48.5) | ||
| Preparing a hot meal | 5 (15.2) | 13 (39.4) | 15 (45.5) | ||
| Telephoning for information | 1 (3.0) | 10 (30.3) | 22 (66.7) | ||
| Total | 10 (30.3) | 18 (54.5) | 5 (15.1) | ||
| Planning | |||||
| Doing daily house cleaning | 0 | 6 (18.2) | 27 (81.8) | ||
| Preparing a hot meal | 2 (6.1) | 7 (21.2) | 24 (72.8) | ||
| Telephoning for information | 2 (6.1) | 9 (27.2) | 22 (66.7) | ||
| Making a budget | 5 (15.2) | 10 (30.3) | 18 (54.5) | ||
| Total | 8 (24.2) | 14 (42.2) | 11 (33.3) | ||
| Carrying out the task | |||||
| Doing daily house cleaning | 3 (9.1) | 3 (9.1) | 6 (18.2) | 0 | 21 (63.6) |
| Preparing a hot meal | 4 (12.1) | 3 (9.1) | 3 (9.1) | 2 (6.1) | 21 (63.6) |
| Telephoning for information | 5 (12.2) | 4 (12.1) | 1 (3.0) | 2 (6.1) | 21 (63.6) |
| Making a budget | 3 (9.1) | 7 (21.2) | 0 | 2 (6.1) | 21 (63.6) |
| Total | 10 (30.3) | 4 (12.1) | 2 (6.1) | 3 (9.1) | 14 (42.5) |
| Verifying goal attainment | |||||
| Doing daily house cleaning | 1 (3.0) | 3 (3.0) | 29 (87.9) | ||
| Preparing a hot meal | 3 (9.1) | 8 (24.2) | 22 (66.7) | ||
| Telephoning for information | 3 (9.1) | 8 (24.2) | 22 (66.7) | ||
| Making a budget | 1 (3.0) | 8 (24.2) | 24 (72.7) | ||
| Total | 5 (15.2) | 12 (36.4) | 16 (48.5) | ||
Table 4 presents level of independence according to their result on the AES. Based on the total score of the ADL Profile, not a single participant with apathy was categorised as independent. Specifically for formulating a goal, 44.4% of the apathetic participants were dependent and 55.6% required assistance. In the ILS, 77.8% were dependent in the apathetic participants subgroup as compared to 20% in the non-apathetic one.
ADL Profile uses the term Assistance whereas ILS uses the term semi-independence.
Table 4Level of independence according to presence of apathy.
| Participants | Level of independence, n (%) | ||||
|---|---|---|---|---|---|
| Dependence | Assistance/Semi-independence | Independence | p-value | ||
| ADL Profile | Doing daily house cleaning | 0.029 | |||
| Apathetic (n = 18) | 3 (16.7) | 13 (72.2) | 2 (11.2) | ||
| Non-apathetic (n = 15) | 2 (13.3) | 5 (33.3) | 8 (53.4) | ||
| Preparing a hot meal | 0.239 | ||||
| Apathetic (n = 18) | 5 (27.8) | 8 (44.4) | 5 (27.8) | ||
| Non-apathetic (n = 15) | 2 (13.3) | 4 (26.7) | 9 (60.0) | ||
| Telephoning for information | |||||
| Apathetic (n = 18) | 7 (38.9) | 7 (38.9) | 4 (22.2) | 0.024 | |
| Non-apathetic (n = 15) | 1 (6.7) | 4 (26.7) | 10 (66.7) | ||
| Total score | 0.023 | ||||
| Apathetic (n = 18) | 10 (55.6) | 8 (44.4) | 0 | ||
| Non-apathetic (n = 15) | 3 (20.0) | 8 (53.3) | 4 (26.7) | ||
| ILS | Total score | 0.002 | |||
| Apathetic (n = 18) | 14 (77.8) | 2 (11.1) | 2 (11.1) | ||
| Non-apathetic (n = 15) | 3 (20.0) | 9 (60.0) | 3 (20.0) | ||
† Fisher exact test.
4. Discussion
To our knowledge, this is the first study to assess IADL accomplishment in adults with the childhood phenotype of DM1. Our findings indicate that a large proportion are dependent or need help to accomplish IADLs, which may lead to frequent participation restrictions.
Results of the study indicate a high level of dependence for many individuals based on the cut-off scores of the ILS and ADL Profile (39.4% and 51.5% respectively) (Table 2). This study suggests a worse pattern of participation restrictions than the one documented in the adult phenotype by Gagnon et al. [
[27]
]. Regarding home management, our study has found higher level of dependence or human help needed (66.7%) compared to their study, in which 53.5% participants reported having disrupted participation in housing [[27]
]. It could be explained by two factors: (1) a worse clinical profile due to the difference of phenotypes (adult vs childhood) or (2) the use of a self-reported questionnaire in Gagnon et al. whereas we used performance-based measures. Financial management was the most affected IADL, which is in line with the exploratory study where only 2/11 participants were independent [[15]
]. The high proportion of school-related difficulties could be an explaining factor as financial management involves mathematical operations. In fact, only 24.2% of our sample completed high school level, as opposed to 80.1% of the general population of Quebec, Canada [[28]
]. Considering that all participants were either dependent (72.7%) or semi-independent (27.3%), this study highlights their crucial need for support in this important IADL.ILS scores from other populations are available for comparison (see Supplemental Table 1). The data of these other populations were retrieved from the ILS manual, where the author explains they collected data for the standardization from a clinical sample of 248 adults, 17 years and older, with various diagnoses [
[20]
]. All three IADL scores of adults with childhood phenotype of DM1 are similar to the borderline IQ population, but lower than people with mild to moderate traumatic brain injury. According to the ADL Profile, verbal assistance was required for 27.3–39.4% of participants in the four IADL assessed. The need for physical assistance was less frequent, which reinforces the claim of previous studies that muscle strength and mobility are not major clinical problems in the childhood phenotype, as opposed to the adult-onset phenotypes [[14]
,[29]
. Indeed, even though half of our participants had proximal weakness as measured by the Muscular Impairment Rating Scale (MIRS), physical assistance was rarely required to accomplish IADL, except for daily house cleaning, which was the most physically demanding activity assessed in the study.The second objective of this paper was to explore the impact of executive functions and apathy on ADL accomplishment among this population. Formulating a goal was the most challenging operation for participants. Almost one third of the sample was dependent in this operation, meaning that despite the assistance offered (i.e., hints, guidance), they still could not identify or formulate a goal (for example the need to prepare a meal during lunchtime). These results tie well with frequently observed apathy in DM1 reaching 55% in the largest sample [
[30]
]. Apathy is manifested by reduced goal-directed behavior which may explain the stimulation required for some activities and highlight its impact on accomplishing everyday activities. Regarding planning, two thirds of participants were either dependent or required assistance in the total score. Thirty percent of our participants required assistance for planning a budget, and 15% were still not able to complete this task despite the help offered by the evaluator.Regarding operations related to executive functioning, some further hypothesis could be drawn. In simple activities such as grooming, only stimulation to initiate the activity was required. Contrastively, in more complex activities (IADL), such as meal preparation, supervision and sometimes even verbal assistance was required to initiate and plan activities. Finally, in the most complex activities (telephoning for information or making a budget), verbal assistance and guidance were definitely required, even sometimes compensating completely for the participant. This underlines that most childhood phenotype individuals are frequently confronted to difficulties and require help to perform IADLs because these activities require higher levels of cognitive functioning (i.e., executive abilities).
To our knowledge, this is the first time that the impact of executive functions and apathy on IADL is so clearly demonstrated in this population. This study reflects that interventions should target apathy and executive impairments (such as the difficulty to formulate goals) first and foremost, as it is a pivotal point in these patients’ participation restrictions. This is consistent with the findings from Van Heugten et al. where apathy was one of the principal factors for lower participation [
[31]
]. These authors suggested neuropsychological rehabilitation to compensate for central nervous system-related problems and their impact on participation.This study identifies the need for help in several key areas to maintain independent living including financial management. Home services such as housekeeping are often offered based on physical limitations but the results in our sample suggest that other factors such as presence of apathy and executive impairments should also be considered. Moreover, a brief screening of the perceived level of independence showed that our participants did not consider themselves dependent and only a third considered that they needed help, even though our results suggest otherwise. International management guidelines have recently emphasised the need for annual multidisciplinary assessment where support could be offered before the difficulties and drastic situations emerge [
[32]
]. There should be a systematic follow-up for all childhood-phenotype patients to prepare them and their relatives in what might be harder throughout their future life.This study has potential limitations that should be noted. The small sample size and over-representation of women limit the generalization of our results: a large international study should be conducted. Outcome measures with documented metrological properties are lacking in this population, which could influence the interpretation of the data. In the absence of validated cut-off scores within the target population (i.e., DM1), the use of cut-off scores developed in other conditions, even though well-validated, may have raised potential biases. However, for the assessment of apathy, a very conservative cut-off score has been used (i.e., + 2 S.D. over healthy elderly participants) to avoid internal bias. Moreover, not all IADL were assessed in this study. Finally, it would have been interesting to include motor assessment in this protocol and should be considered for future research.
5. Conclusion
This cross-sectional study demonstrated that adult individuals living with the childhood phenotype experience important difficulties in accomplishing IADL, which therefore negatively affects their ability to reach independent living. Moreover, this study showed the important contribution of executive impairments and apathy in the difficulties encountered to perform IADL in childhood DM1 individuals. This study highlights the importance to offer services aimed to support independent living into their adult life. Longitudinal studies describing the trajectory of IADL difficulties throughout the lifespan would permit to better inform prognosis and anticipatory guidance.
Conflicts of interest
None.
Acknowledgements
The authors wish to thank the participants and families who donated their time to this research study. The study was funded by the Association française contre les myopathies (AFM) (BG holds a Trampoline grant #22302). CG holds a career-grant funding from the Fonds de recherche du Québec en Santé (#31011). This study was accomplished as part of Samar Muslemani's Master's Training in health sciences, which was funded by the Corporation de recherche et d'action sur les maladies héréditaires (CORAMH), the Programme de soutien au développement de la mission universitaire and the Fonds de la recherche du Québec en Santé (#272862). We would also like to thank Justine Dolbec for the apathy assessment. The authors have stated that they had no interests which might be perceived as posing a conflict or bias.
Appendix. Supplementary materials
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Article info
Publication history
Published online: February 13, 2022
Accepted:
February 9,
2022
Received in revised form:
February 5,
2022
Received:
July 5,
2021
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