Keywords
Motor Activity - International Classification of Functioning, Disability and Health
- Motor Neuron Disease - Neuromuscular Junction Diseases - Social Participation
INTRODUCTION
Rehabilitation seeks to reduce vulnerability and improve the quality of life of individuals
with disabilities by enhancing their daily performance. For an effective intervention,
health professionals must have a clear understanding of each patient's abilities and
limitations. Standardized protocols to assess health status and physical functioning
are essential tools to monitor treatment outcomes and guide rehabilitation strategies.[1]
Furthermore, the development of new pharmacological therapies has heightened the demand
for precise and sensitive outcome measures. Participation, understood as the opportunity
to exercise citizenship and autonomy—including concepts such as freedom, agency, and
subjectivity—has become a central focus in rehabilitation. Addressing participation
requires integrating the individual and collective dimensions of care, which can pose
challenges in the clinical practice, particularly for physiotherapists.[2]
Individuals with neuromuscular disorders (NMDs) commonly experience progressive muscle
weakness, loss of functional independence, and significant impairments in daily activities.[3]
[4] Many are unable to perform basic tasks such as rising from a chair, climbing stairs,
or taking a shower.[5]
[6] These limitations in self-care often result in reduced social participation.
The Activity Limitation Measure (ACTIVLIM), developed and validated by Vandelverde
et al.,[7] is a self-reported instrument designed to assess perceived limitations in daily
self-care activities. Based on the concept of activity limitation as defined by the
International Classification of Functioning, Disability and Health (ICF), the ACTIVLIM
is a unidimensional questionnaire that addresses domains such as mobility, self-care,
and domestic activities. It evaluates basic body movements associated with tasks in
which individuals with NMDs may require assistance or support.[8]
Although the ACTIVLIM addresses highly-relevant aspects of functioning—particularly
independence in self-care and mobility—its use in different cultural and linguistic
contexts requires rigorous adaptation. The cross-cultural adaptation of clinical assessment
tools must follow a systematic process to preserve the instrument's content, psychometric
properties, and validity. Ensuring semantic and psychometric equivalence in the translated
version is essential for its reliability and clinical usefulness.[9]
[10]
Therefore, the aim of the present study was to translate, cross-culturally adapt,
and validate the Brazilian Portuguese version of the ACTIVLIM, assessing its psychometric
properties in individuals with NMDs.
METHODS
The present cross-sectional observational study was approved by the Ethics in Research
Committee of Hospital das Clínicas da Faculdade de Medicina da Universidade de São
Paulo (HCFMUSP), under protocol number 3.264.694. Prior to initiating the translation
and cross-cultural adaptation processes of the ACTIVLIM, authorization was obtained
from the Physical Medicine and Rehabilitation Unit of Université Catholique de Louvain,
the original developers of the scale.
Translation and cross-cultural adaptation
The translation and adaptation processes followed the six standardized steps proposed
by Beaton et al.:[9]
-
Initial translation from English to Brazilian Portuguese by two independent translators,
one of whom was a physiotherapist;
-
Synthesis of the two translations into a single version;
-
Back-translation of the synthesized version into English by two native English speakers
blinded to the original version;
-
Expert committee review, including specialists in neuromuscular diseases, methodology,
and linguistics;
-
Pretesting of the prefinal version to assess comprehensibility and clarity in a sample
of 60 individuals with NMDs; and
-
Assessment of psychometric properties, including reliability and validity.
Participants and inclusion criteria
The participants were recruited from the Neurology Clinic at HCFMUSP between August
2018 and July 2019. All individuals who met the inclusion criteria and agreed to participate
signed an informed consent form. In total, 268 participants were included in the study.
For minors, assents were obtained from the child, and informed consent was signed
by their parents or legal guardians.
The eligible participants had confirmed diagnoses of NMDs, including spinal muscular
atrophy (SMA), Steinert's myotonic dystrophy, limb-girdle muscular dystrophy, dystrophinopathies
(Duchenne/Becker), congenital myopathies, hereditary facioscapulohumeral dystrophy,
inflammatory myopathies, acquired neuropathies, amyotrophic lateral sclerosis (ALS),
and investigational myopathies and myasthenias. All diagnoses were confirmed though
genetic testing. Sociodemographic data such as age and level of schooling were collected
at the time of evaluation ([Table 1]).
Table 1
Characteristics of the study sample
|
n (%)
|
|
Gender
|
Male
|
148 (55%)
|
|
Female
|
120 (45%)
|
|
Age (range: 6–78 years)
|
Children (range: 6–15; Mean: 9.4 years)
|
25 (10%)
|
|
Adults (range: 16–78; Mean: 42.4 years)
|
243 (90%)
|
|
Mean age
|
|
39.3 years
|
|
Schooling* (mean: 9.6 years)
|
Range: 4–16 years
|
|
Disease stages
|
Gait
|
226 (84%)
|
|
Wheelchair
|
42 (16%)
|
|
Diagnosis classification
|
Spinal muscular atrophy
|
18 (7%)
|
|
Steinert's myotonic dystrophy
|
32 (12%)
|
|
Congenital dystrophy and/or myopathy
|
22 (8%)
|
|
Girdle muscular dystrophy
|
37 (14%)
|
|
Dystrophinopathies (DMD/DMB)
|
23 (9%)
|
|
Fascioescapulohumeral
|
10 (4%)
|
|
Inflammatory myopathy
|
16 (6%)
|
|
Mitochondrial myopathy
|
33 (12%)
|
|
Others**
|
77 (28%)
|
|
Rating average
|
ACTIVLIM
|
25.1
|
|
Vignos scale
|
2.0
|
|
Brooke scale
|
3.5
|
|
MIF
|
102.2
|
|
Standard deviation
|
ACTIVLIM
|
8.6
|
|
Vignos
|
1.2
|
|
Brooke
|
2.0
|
|
MIF
|
19.4
|
Abbreviations: ACTIVLIM, Activity Limitation Measure; BMD, Becker muscular dystrophy;
DMD, Duchenne muscular dystrophy; FIM, Functional Independence Measure.
Notes: *In children, we considered the parents' education. **Neuropathies, myasthenia,
amyotrophic lateral sclerosis, myopathies under investigation.
Assessment
The assessment protocol was structured according to the conceptual framework of the
ICF, which provides a comprehensive model to illustrate the relationships among health
conditions, functioning, and contextual factors.[11]
The ACTIVLIM, which can be applied to adults and children, comprises 22 items: 18
of them are common to all age groups, covering domains such as dressing, personal
hygiene, fine motor skills, walking, and stair navigation; and 4 are age-specific
items. For individuals aged 16 years and older, the additional items include carrying
a heavy package, getting into a car, walking more than 1 kilometer, and standing for
long periods. For children aged 6 to 15 years, age-appropriate items include closing
a door, jumping on one foot, putting on a backpack, and running.[7]
With this structure, the ACTIVLIM can be used across the lifespan, enabling longitudinal
tracking of functional changes in individuals with NMDs. It facilitates comparisons
among patients of different age groups with the same diagnosis, thus capturing the
clinical heterogeneity of myopathies, dystrophies, neuropathies, and motor neuron
diseases. The total score ranges from 0 to 36, with higher scores indicating greater
functional independence. The use of assistive devices and environmental adaptations
may influence performance and should be considered during interpretation.[8]
The ACTIVLIM is based on the Rasch model, a probabilistic model that places item difficulty
and individual ability on a common linear scale, enabling precise and reliable measurements.[7] This model enhances the clinical applicability of the scale by ensuring interval-level
properties and robust psychometric characteristics ([Table 2]).
Table 2
Translation of the questions of the Activity Limitations Measure (ACTIVLIM)
|
How difficult are the following activities?
|
Qual a sua dificuldade nas seguintes atividades?
|
|
1
|
Putting on a T-shirt
|
Vestir uma camiseta
|
|
2
|
Washing one's upper body
|
Lavar o corpo da cintura para cima
|
|
3
|
Dressing one's lower body
|
Vestir-se da cintura para baixo
|
|
4
|
Taking a shower
|
Tomar banho no chuveiro
|
|
5
|
Sitting on the toilet
|
Sentar-se no vaso sanitário
|
|
6
|
Taking a bath
|
Tomar banho de banheira (ou piscina)
|
|
7
|
Walking downstairs
|
Descer escadas
|
|
8
|
Stepping out of a bathtub
|
Entrar e sair do box no banheiro
|
|
9
|
Opening a door
|
Abrir uma porta
|
|
10
|
Walking outdoors on leveled ground
|
Andar em locais planos fora de casa
|
|
11
|
Washing one's face
|
Lavar o rosto
|
|
12
|
Hanging up a jacket on a hatstand
|
Pendurar um casaco no armário
|
|
13
|
Wiping one's upper body
|
Enxugar o rosto, as mãos e os braços
|
|
14
|
Walking upstairs
|
Subir escadas
|
|
15
|
Carrying a heavy load
|
Carregar um pacote pesado
|
|
16
|
Getting into a car
|
Entrar no carro
|
|
17
|
Standing for a long time (±10 min)
|
Ficar em pé por muito tempo (±10 min)
|
|
18
|
Walking more than 1 kilometer
|
Andar mais de 1 quilômetro
|
|
19
|
Closing a door
|
Fechar uma porta
|
|
20
|
Hopping on one foot
|
Pular num pé só
|
|
21
|
Putting on a backpack
|
Colocar uma mochila
|
|
22
|
Running
|
Correr
|
To complement the evaluation, the following scales were used:
-
Vignos scale: This staging system evaluates lower-limb function in individuals with
NMDs. It consists of 10 levels (0–10), considering walking ability, stair use, transitions
such as rising from a chair or sitting, and dependence on assistive devices.[12] Higher scores reflect greater functional impairment.
-
Brooke Upper Extremity Scale: Comprising 6 levels (1–6), this scale assesses upper-limb
function, particularly tasks involving arm elevation and bringing the hands to the
mouth.[13] As with the Vignos scale, higher scores indicate more severe limitations.
-
Functional Independence Measure (FIM): A widely-used tool to assess disability and
care burden, it includes 18 items distributed across domains such as self-care, mobility,
bowel and bladder control, communication, and social cognition. Each item is scored
from 1 (total dependence) to 7 (complete independence), with the total score ranging
from 18 to 126.[14]
-
Medical Research Council (MRC) scale: Used to grade muscle strength in individual
muscle groups on a scale from 0 to 5: 0 = no contraction; 1 = flicker/trace of contraction;
2 = active movement with gravity eliminated; 3 = active movement against gravity;
4 = active movement against some resistance; and 5 = normal strength. A strength index
was also calculated using the formula MRC index = (total score × 100)/(number of muscles
tested × 5), yielding a percentage that reflects global muscle strength.[15]
Statistical analysis
Statistical analyses were conducted using the Statistica software, version 13.0 (StatSoft
Inc.). The psychometric properties of the Brazilian version of the ACTIVLIM were examined
through analyses of reliability, internal consistency, construct validity (external
consistency), and responsiveness.
The inclusion of 60 participants in the assessment of psychometric properties was
based on established guidelines for instrument validation.[9] To assess test-retest reliability, these participants were evaluated twice by the
same rater, with a 1-month interval between sessions. The same subgroup was also assessed
at baseline by a second, blinded rater to test interrater reliability. Intraclass
correlation coefficients (ICCs) were calculated for the intra- and interexaminer reliability,
with values ≥ 0.80 considered indicative of high reliability.[16] After reliability was confirmed through these analyses, the test was applied to
the larger group of 268 patients, ensuring that the psychometric properties of the
instrument were robust and could be generalized.[17]
Internal consistency was evaluated using the Cronbach's alpha. This index reflects
the homogeneity of the items, indicating whether they assess the same construct. Higher
interitem correlations result in increased alpha values, with those ≥ 0.70 generally
considered acceptable.[16]
Construct validity (external consistency) was tested using Spearman's rank correlation
coefficients, adjusted for age, to examine associations involving the ACTIVLIM and
established functional measures: the Vignos scale, the Brooke scale, and the FIM.
To control multiple comparisons, the Bonferroni correction was applied. Bonferroni
correction consists of adjusting the significance threshold to p < 0.017(as a result
of 0.05 / 3, because there were three comparisons). Additionally, the relationship
between the ACTIVLIM and muscle strength (measured by the MRC scale) was also assessed.
Correlation coefficients ≥ 0.80 were interpreted as strong.[18]
The responsiveness of the Brazilian version of the ACTIVLIM was examined using linear
regression analysis, in which the coefficient of determination (R2) was used to estimate the proportion of variance in ACTIVLIM scores explained by
independent variables (such as functional staging and muscle strength). The values
of R2 range from 0 to 1, with higher values indicating a better model fit and greater explanatory
power, relative to the sample size and degrees of freedom (dfs).
RESULTS
For the intra- and interrater reliability analysis, data from 60 participants evaluated
by 2 physiotherapists, with a 1-month interval between assessments, were analyzed.
Values of ICC of 0.95 (intrarater) and 0.90 (interrater) were obtained, indicating
excellent reliability.
Regarding internal consistency, the Cronbach's alpha for the total ACTIVLIM score
was of 0.94, classified as high. The alpha values for individual items also demonstrated
high homogeneity, ranging from 0.94 to 0.95.
For construct validity (external consistency), Spearman's correlation coefficients
(adjusted for age) were calculated. As multiple comparisons were made, a Bonferroni
correction adjusted the significance threshold to p < 0.006 (0.050/8). Strong and statistically significant correlations were observed
regarding the ACTIVLIM and the Vignos scale (r = −0.907), the Brooke Scale (r = −0.908), and the FIM (r = 0.864), with p < 0.001 for all comparisons.
A strong negative correlation was found involving the ACTIVLIM scores and disease
staging using the Vignos and Brooke scales ([Figure 1]). Higher ACTIVLIM scores reflected greater functional independence, while lower
scores were associated with increased disease severity and dependence in daily living
activities.
Figure 1 (A) Relationship between patients' activity measures and the Vignos scale. (B) Relationship between patients' activity measurse and the Brooke scale.
[Figure 2] illustrates the correlations regarding muscle strength assessed by the MRC scale
and ACTIVLIM scores. A strong positive correlation was found involving proximal muscle
strength of the upper (r = 0.748) and lower limbs (r = 0.793) and the ACTIVLIM scores (p < 0.001 for both).
Figure 2 (A) Correlation and relationship between the Activity Limitation Measure (ACTIVLIM)
and proximal muscle strength of the upper limbs (according to the Medical Research
Council [MRC] scale). (B) Correlation and relationship between the ACTIVLIM and proximal muscle strength of
the lower limbs.
Other muscle strength domains showed moderate correlations with the ACTIVLIM scores,
such as trunk muscle strength (r = 0.602), distal upper limb strength (r = 0.512), and distal lower limb strength (r = 0.594), with p < 0.001 for all comparisons.
For a clearer understanding of group characteristics, the participants were categorized
into subgroups according to diagnosis: SMA, congenital muscular dystrophy (CMD), Duchenne/Becker
muscular dystrophy (DMD/BMD), facioscapulohumeral dystrophy (FSH), Steinert's myotonic
dystrophy, congenital myopathy, inflammatory myopathy, mitochondrial myopathy, and
other NMDs (such as, neuropathies, myasthenias, amyotrophic lateral sclerosis, Emery-Dreifuss
dystrophy, and oculopharyngeal dystrophy).
We investigated the correlation between the total ACTIVLIM scores and muscle strength,
assessed by the MRC scale. Using simple linear regression, we identified the variables
that best explained the variance in ACTIVLIM scores:
-
Vignos scale: R2 = 0.8236; estimate = −1.0267; df = 1;
-
Brooke scale: R2 = 0.8132; estimate = −0.9981; df = 1;
-
Proximal lower limb muscle strength: R2 = 0.6480; estimate = 1.0049; df = 1; and
-
Proximal upper limb muscle strength: R2 = 0.5805; estimate = 0.9605; df = 1.
These findings demonstrate that the functional staging scales and proximal muscle
strength are strong predictors of functional independence, as measured by the ACTIVLIM
([Figure 3]).
Figure 3 Correlation of the MRC scale (global muscle strength) and the ACTIVLIM, with the
participants divided by specific diagnosis and linear regression.
DISCUSSION
In the current study, we translated, cross-culturally adapted, and validated the Brazilian
Portuguese version of the ACTIVLIM questionnaire. In line with the ICF, the evaluation
extended beyond body structure and functions, such as muscle strength, incorporating
broader dimensions such as activity, participation, and contextual factors. Functional
measures are increasingly preferred in monitoring NMD progression,[19] and the ACTIVLIM aligns with this perspective by assessing limitations in activities
of daily living.
The translation process followed the guidelines proposed by Beaton et al.,[9] which proved to be effective for developing the Brazilian Portuguese version of
the ACTIVLIM. Subsequent analyses demonstrated excellent reliability: ICCs of 0.95
(intrarater) and 0.90 (interrater), similar to the original study by Vandervelde et
al.[7] (who found values of 0.98 and 0.93 respectively). Comparable results were observed
in the Spanish validation by Pagola et al.,[19] in which 135 adults with myopathies yielded an ICC of 0.96. These findings confirm
the high reproducibility and reliability of the Brazilian Portuguese version.
Internal consistency was also high, with a Cronbach's alpha of 0.94, indicating strong
homogeneity among the questionnaire items. In terms of construct validity, our correlations
involving the ACTIVLIM and the Vignos scale (r = −0.907), the Brooke scale (r = −0.908),
and the FIM (r = 0.864) were similar or stronger than those reported in the original
questionnaire and in the Spanish validation.[7]
[19] These inverse relationships reflect that greater ACTIVLIM scores indicate better
functional independence, while higher scores on the Vignos or Brooke scales denote
increased disability. Thus, the ACTIVLIM complements other tools by incorporating
the patient's perception, which is critical for clinical reasoning and to identify
tasks and muscle synergies to prioritize during therapy.
In the analysis of the ACTIVLIM items, common difficulties involved lower-limb activities
such as climbing up and down stairs, walking outdoors, prolonged standing, and walking
long distances. These challenges align with higher severity levels in the Vignos scale.
Difficulties with upper-limb activities, such as putting on a T-shirt, washing the
upper body, or reaching overhead, correlate with the Brooke scale scores, which reflect
upper-limb mobility and strength.
Most participants reported impairments in lower-limb function. Accordingly, the linear
regression identified proximal lower-limb strength and the Vignos and Brooke scales
as the best predictors of ACTIVLIM scores, supporting the scale's relevance in the
clinical monitoring of NMDs.
Although the FIM and ACTIVLIM demonstrated a strong correlation, they serve different
purposes. The FIM measures overall functional independence and participation in social
contexts,[14] while the ACTIVLIM focuses on self-perceived difficulty in performing daily tasks.
Notably, the ACTIVLIM allows for compensatory strategies but does not account for
assistance from others,[20] which is an important distinction in interpreting patient performance in NMDs, in
which compensatory patterns are common. Clinical observations often reveal altered
postures and gait, such as equinus foot, widened stance, pelvic tilt, lumbar hyperlordosis,
and internal rotation of the shoulders,[21] reflecting strategies to overcome antigravity muscle weakness.
Previous studies[13] have primarily explored the relationship between muscle strength and motor function
in DMD. In the current study, this relationship extended to other NMDs, with strong
correlations involving the ACTIVLIM and proximal upper- and lower-limb strength. As
reported by Vandervelde et al.,[22] shoulder and elbow flexors are essential for tasks such as washing the face or putting
on a T-shirt, while hip and knee flexors contribute to climbing stairs or stepping
out of a bathtub.
Manual muscle testing (MMT) and dynamometry remain essential for the clinical evaluation.
While dynamometry quantifies peak force, MMT provides qualitative insights on movement
patterns and gravity resistance. When applied by experienced clinicians, MMT demonstrates
good reproducibility and is especially valuable in clinical reasoning for individuals
with NMDs.[23]
[24] Functional assessments such as the ACTIVLIM add contextual depth to strength testing
by linking impairments with daily challenges.
Nunes et al.[23] also demonstrated strong correlations between proximal and distal muscle strength
in the Motor Function Measure (MFM), particularly in tasks involving trunk stability—critical
for transfers and mobility. Our findings reinforce this: proximal strength in the
upper and lower limbs correlated strongly with the ACTIVLIM scores (r = 0.748 and
0.793 respectively), supporting the importance of trunk and limb stability for complex
tasks such as climbing stairs or hanging clothes.[6]
Bakker et al.[25] found that muscle strength, as measured by the MRC scale, could predict gait loss
in DMD. Hip extensor strength ≤ 2 and dorsiflexor strength ≤ 4 were associated with
increased risk. Combining the MRC and the ACTIVLIM may enhance clinical monitoring
in NMDs. Future studies should investigate the responsiveness of these instruments
in combination.
Finally, incorporating the patient's perspective—as captured by the ACTIVLIM—and adopting
patient- and family-centered care practices broadens the focus of rehabilitation.[23]
[26] There is evidence[27]
[28] that engaging patients in goal-setting improves therapy adherence, functional outcomes,
pain management, range of motion, and strength. Thus, the ACTIVLIM is a valuable tool
to integrate patient-reported outcomes into clinical decision-making for individuals
with NMDs.
In conclusion, the Brazilian Portuguese version of the ACTIVLIM demonstrated excellent
reliability, internal consistency, and strong construct validity through significant
correlations with functional staging, independence measures, and muscle strength.
By assessing patients' self-perception of activity limitations–particularly in self-care
and mobility—the ACTIVLIM offers a meaningful and sensitive tool to evaluate the functional
impact of NMDs.
Aligned with the ICF framework and centered on patient-reported outcomes, the ACTIVLIM
complements clinical assessments and supports individualized rehabilitation planning.
Its use is recommended in the routine clinical practice and research in Brazil, and
future studies should explore its responsiveness to interventions and longitudinal
applicability in diverse care settings.
Bibliographical Record
Ana Carolina Costa Santos, Daniela Melo de Almeida, Nathalia de Brito Pereira, André
Macedo Serafim Silva, Edmar Zanoteli, Mariana Callil Voos. Brazilian version of the
ACTIVLIM: translation, cultural adaptation, and validation for neuromuscular disorders.
Arq Neuropsiquiatr 2026; 84: s00451814398.
DOI: 10.1055/s-0045-1814398