Co-sleeping in school-aged children with a motor disability: a comparative population-based study
Abstract
Aim
To determine the prevalence and determinants of co-sleeping in school-aged children with a motor disability compared with the school-aged general population.
Method
A questionnaire on demographic characteristics and co-sleeping habits, along with the Sleep Disturbance Scale for Children (SDSC), was sent to parents of children aged between 4 years and 18 years followed in our tertiary paediatric neurorehabilitation clinic, and to school-aged children in a representative sample of state schools.
Result
We analysed responses for 245 children with motor disability (142 males, 103 females; mean age 10y 6mo, standard deviation [SD] 3y 10mo, range 4–18y) and 2891 of the general population (1484 males, 1497 females; mean age [SD] 9y 6mo [3y 5mo], range 4–18y) (response rates 37% and 26% respectively). Cerebral palsy was the most common diagnosis among children with motor disability. Weekly co-sleeping was significantly more common in children with motor disability than in the general population (11.8% vs 7.9% respectively, p=0.032). Special care of the child with motor disability at night, mainly addressing epilepsy, was reported as a cause of co-sleeping by two-thirds of parents. Factors associated with co-sleeping in the motor disability group were age, housing crowding, severe visual impairment, and pathological sleep according to the SDSC.
Interpretation
Co-sleeping is common among children with motor disability. It is influenced by personal and medical factors, as well as the requirements for special care at night. Therefore, health professionals should explore sleeping arrangements in families of children with motor disability.
What this paper adds
- Co-sleeping is common among school-aged children with motor disability.
- Nocturnal care requirements of children with motor disability generate co-sleeping.
- Co-sleeping influences the sleep of parents of children with motor disability.
This article is commented on by Gringras on pages 349–350 of this issue.
Abbreviation
-
- SDSC
-
- Sleep Disturbance Scale for Children
Children with motor disabilities caused by conditions such as cerebral palsy (CP), neuromuscular diseases, or other genetic disorders experience sleep difficulties more often than their healthy peers.1 Several factors may interfere with their sleep, for example epileptic seizures, mobilization by an adult because of lack of mobility, and special care requirements such as tube feeding. Therefore, night-time can represent a demanding and stressful period for parents and caregivers, with a potential impact on their sleep quality.2 As a consequence, parents may choose to sleep with their child for reassurance and/or to provide care during the night, having easier access than if they were in a separate room.
Co-sleeping does not have a uniform definition. It may imply bed- or room-sharing for all or part of the night, and does not necessarily refer to a child sleeping with a parent, because other family members (e.g. siblings) may be involved. Co-sleeping is a longstanding and worldwide practice with a prevalence ranging from 6% to 70% depending on the age of the child, the region of the world, and several other sociocultural determinants.3, 4 For example, unlike Asian cultures in which interdependence of family members is valued, Western societies usually discourage the practice of co-sleeping, as early independence for sleep is praised and encouraged.5 In Switzerland, regular co-sleeping defined as occurring at least once per week was reported with the highest occurrence at 4 years of age (38.1%), decreasing with older age, but still applied to 22.1% of 8-year-old children.6 Co-sleeping in children with a neurodevelopmental disorder has been explored in a few studies, in particular in children with CP. In their study on sleep disorders in children with CP, Newman et al.7 found that 22.9% of the children co-slept at least weekly, and this was positively associated with sleep disorders. In a different sociocultural setting, Atmawidjaja et al.8 found a 76% rate of co-sleeping in children with CP, and there was no significant association with sleep disorders. For children with severe psychomotor impairments of various origins Tietze et al.2 reported a 24% rate of frequent, at least three times a week, co-sleeping. For children with Duchenne muscular dystrophy, Bloetzer et al.9 found a 20.3% rate of at least weekly co-sleeping. Therefore, the rate of co-sleeping and its possible association with sleep disorders differs among children with motor disabilities.
The objective of this study was to determine the rate of co-sleeping among school-aged children with a motor disability and to investigate medical and personal factors associated with co-sleeping. We hypothesized that co-sleeping would be more common in children affected by a motor disability than in peers with no chronic health conditions, and that this would be influenced by the severity of the neurological impairment, associated sleep disorders, and special requirements at night.
Method
We conducted a cross-sectional population-based study by questionnaire, including children with motor disability and a representative sample of school-aged children with no chronic medical condition from the general population. The study was approved by the regional ethics committee.
Participants
For the group with motor disability, we invited 666 school-aged children and their parents to participate in the study in September 2013. A reminder letter was sent in December to the families that had not responded. The inclusion criteria were (1) follow-up at the tertiary paediatric neurology and neurorehabilitation unit at Lausanne University Hospital; (2) age from 4 to 18 years – that is, school-aged children; (3) motor disability related to the following diagnostic categories: cerebral palsy, genetic syndromes (e.g. Rett, Wolf–Hirschhorn), other encephalopathies (e.g. acquired brain injuries, encephalopathies of various origin), neuromuscular diseases (e.g. muscular dystrophies, congenital myopathies), or spinal and peripheral nerve lesions (e.g. spinal dysraphism, obstetrical brachial plexus palsy). All these diagnoses were ascertained by the specialists of the paediatric neurology and neurorehabilitation unit, the only reference centre for motor disabilities in the region (canton of Vaud, Switzerland, 2013 population=743 000 inhabitants), which follows up the vast majority of affected children in the catchment area. We used the classification of CP subtypes described by Rosenbaum et al.10 to categorize our CP sample further (unilateral spastic, bilateral spastic, dyskinetic, and ataxic).
For the group from the general population, we obtained authorization from the regional Department of Education to contact a given list of primary and secondary state schools. The Department of Education performed the sampling to obtain a group that was representative of the general population. We included the 11 400 school-aged children listed in these schools, all aged between 4 years and 18 years. Children reported by their responding parent as having a chronic medical condition were excluded. Secondary schools were invited in September 2013; primary schools in September 2014.
All participants received an invitation letter with the questionnaire described below, a consent form and a return stamped envelope. For participants in the motor disability group we used our unit's address database and sent the documents by post. For the general population sample, the documents were delivered to the selected primary and secondary schools and distributed to the children by the teaching staff.
Questionnaire
The paper questionnaires for both the participants with motor disability and the general populations were to be completed by the parents. The questionnaire specifically explored the previous 6 months and included three sections. The first section explored co-sleeping with multiple choice questions about bed- and room-sharing, with occurrence ranging from never to every night; parental fear of an adverse event to their child at night and its relation to co-sleeping; the impact of co-sleeping on child's and parental sleep quality; and co-sleeping as a source of conflict between family members. For the motor disability group we added questions exploring comorbidities such as epilepsy and its severity (through the number of medications and ongoing seizures), severe visual impairment as well as child care at night such as tube feeding (nasogastric tube or gastrostomy), mobilization, and orthotics. Additionally, we reviewed the medical files of the responding children with motor disability to collect information regarding intellectual disability and its severity, as well as mobility. We used the Gross Motor Function Classification System (GMFCS) level for children with CP, as described in the GMFCS – Expanded and Revised version.11 We further categorized those in GMFCS levels I to III as walkers, and those in GMFCS levels IV to V as non-walkers, to allow classification of children without CP.
The second section explored demographic characteristics such as age and sex of the children, origin, educational level, and employment status of the parents. We defined ‘housing crowding’ by dividing the number of family members living in the household by the number of bedrooms in the house. To determine the origin of the parents, we used a listing of countries and regions of the world, according to the 2011 demographic statistics of the foreign population in the canton of Vaud.
The third section consisted of the French version of the Sleep Disturbance Scale for Children (SDSC), developed and validated on a sample of 1157 healthy children by Bruni et al.,12-14 further translated and validated in French. It is a Likert-type scale with 26 items divided into six categories of sleep disturbance subscale: difficulty in initiating and maintaining sleep, sleep breathing disorders, disorders of arousal, sleep-wake transition disorders, disorders of excessive somnolence, and sleep hyperhidrosis. The sum of these six subscores forms a total sleep score, with higher scores indicating sleep difficulties. We used the scores for the SDSC obtained from our general population sample to determine normative data for our local child population and calculate T scores. A T score above 70 (standard deviation [SD] ≥2) indicated a pathological sleep.
Each questionnaire was printed with a unique barcode, which offered the possibility to automatically extract the data towards a Microsoft Excel (Microsoft, Redmond, WA, USA) file through scanning with the program Teleform (Cardiff Software, Hewlett-Packard, Palo Alto, CA, USA). We reviewed the scans for potential errors. The identity of responding children with motor disability was requested, which allowed us to collect the necessary data from their medical files. After data collection, we only used the barcode to identify the participants with motor disability. For the children from the general population no identification data besides the questionnaire's barcode were available.
Statistical analysis
We performed univariate analyses with Wilcoxon rank sum tests for unpaired numerical data, and χ2 tests for the categorical data. The adjusted prevalences for co-sleeping were determined through univariate generalized linear models, integrating factors that differed significantly between the participants with motor disability and the general population as covariates. Association analyses with the binary outcome co-sleeping were performed with unconditional simple logistic regression, providing crude odd ratios (ORs). For the potential association of co-sleeping with our diagnostic groups, we used children with unilateral CP as the baseline group in the categorical logistic regression, and reunited the bilateral spastic CP with dyskinetic CP to form a ‘bilateral CP’ group, large enough for comparison with other diagnostic groups. All the variables found to have an association with a value of p<0.20 were introduced in a single step as explanatory variables in a multiple logistic regression, providing adjusted OR. The goodness-of-fit of the model was assessed with the Hosmer–Lemeshow test (a p<0.10 indicates a lack of fit). Significance values were set at p<0.05. We did not replace missing data through imputation. All descriptive and explanatory analyses were performed with STATA 13 (StataCorp, 2013, College Station, TX, USA), tables were generated with STATA 13 and Excel.
Results
We collected responses for 245 children with motor disability and 3088 children from the general population, with response rates of 37% and 26% respectively. We excluded 107 of the responses from the general population because of the presence of a chronic medical condition, leaving a remainder of 2981 participants. The general demographic characteristics of both populations are summarized in Table 1. There were significant differences between the group with motor disability and the group from the general population: sex ratio (male:female 1.38 (142:103) vs 0.99 (1484:1497) respectively), age (mean 10y 6mo, SD 3y 10mo, range 4–17y vs mean 9y 6mo, SD 3y 5mo, range 4–18y), parental origin with more Swiss among the parents of children with motor disability (53.6% vs 37.5%, p<0.001), and total parental educational level with parents in the motor disability group attaining a lower score. The medical characteristics of the children with motor disability are shown in Table 2. CP was the most common diagnosis for children with motor disability (44.5%), mainly of the bilateral spastic type. Three-quarters of the children with motor disability were walkers. Intellectual disability was noted in almost half of the responders; epilepsy in a quarter.
| General characteristics | Motor disability (n=245) | General population (n=2891) | p |
|---|---|---|---|
| Questionnaire completed by the mother | 87.3% | 84.8% | 0.292 |
| Sex ratio (M:F) | 1.38 | 0.99 | 0.014 |
| Age, mean (SD) | 10y 6mo (3y 10mo) | 9y 6mo (3y 5mo) | <0.001 |
| Age group, y | |||
| 4–8 | 34.3% | 42.4% | 0.013 |
| 9–13 | 39.2% | 41.9% | 0.410 |
| 14–18 | 26.5% | 15.7% | <0.001 |
| Parental status | |||
| Single | 18.9% | 19.2% | 0.901 |
| At least one unemployed | 3.0% | 5.3% | 0.133 |
| Parental origin | |||
| Both Swiss | 53.6% | 37.5% | <0.001 |
| Both from Europe | 39.3% | 40.6% | 0.489 |
| At least one from outside Europe | 8.1% | 21.9% | <0.001 |
| Parental educational level, (SD) (2–12, 12=highest level) | 7.52 (2.83) | 8.23 (3.08) | <0.001 |
| Housing crowding (person/room) | 1.32 | 1.48 | <0.001 |
| Co-sleepinga | |||
| Any time in the last 6mo | 38.9% | 35.0% | 0.211 |
| At least once per week | 11.8% | 7.9% | 0.032 |
| Every night | 7.3% | 2.4% | <0.001 |
| Co-sleeping, adjusted prevalencea | |||
| Any time in the last 6mo | 42.1% | 34.4% | 0.022 |
| At least once per week | 11.6% | 7.7% | 0.042 |
| Every night | 7.9% | 2.2% | <0.001 |
- Bold figures indicate statistical significance (p<0.05). aAdjusted for sex, age, parental origin, parental educational level, and housing crowding.
| Medical characteristics | n (%) |
|---|---|
| Cerebral palsy | 109 (44.5) |
| Spastic unilateral | 46 (18.8) |
| Spastic bilateral | 53 (21.6) |
| Dyskinetic quadriplegia | 10 (4.1) |
| Neuromuscular diseases | 23 (9.4) |
| Encephalopathies | 35 (14.3) |
| Syndromes | 64 (26) |
| Spinal/peripheral nerves diseases | 14 (5.7) |
| GMFCS levels I–III/walkers | 184 (75.1) |
| GMFCS levels IV–V/non-walkers | 61 (24.9) |
| Epilepsy | 60 (24.5) |
| Drug resistant | 27 (11) |
| Severe visual impairment | 17 (6.9) |
| Intellectual disability | 121 (44.8) |
| Mild | 35 |
| Moderate | 23 |
| Severe/profound | 55 |
| Tube feeding | 17 (6.9) |
| Non-invasive ventilation | 1 (0.4) |
| Nocturnal orthosis | 41 (16.7) |
- GMFCS, Gross Motor Function Classification System.
Co-sleeping characteristics are described in Tables 1 and 3. The majority of co-sleeping implied bed-sharing for both the children with motor disability those from the general population (81.1% vs 82.5% respectively, p=0.724). There was a statistically significant difference between the reported rate of weekly co-sleeping of participants with motor disability and the general population (11.8% vs 7.9%, p=0.032), stronger for daily co-sleeping (7.3% vs 2.4%, p<0.001). After adjusting the prevalences of co-sleeping for demographic factors, the rate of co-sleeping at any time during the previous 6 months was also significantly higher for children with motor disability. Compared with parents of children from the general population, co-sleeping parents of children with motor disability reported in a significantly greater proportion a fear of an adverse event at night. One-third of parents of children with motor disability practicing co-sleeping mentioned that this fear led to co-sleeping, and two-thirds that co-sleeping was mainly caused by the need for special care of the child at night, mostly because of epilepsy. Parents of children with motor disability reported a more positive impact of co-sleeping on their child's sleep, but a more negative one on the mother's sleep quality.
| Co-sleepers | Motor disability (n=95) | General population (n=1037) | p |
|---|---|---|---|
| Bed-sharing | 81.1% | 82.5% | 0.724 |
| Co-sleeping because of fear of an incident at night | 32.6% | 4.3% | <0.001 |
| Co-sleeping because of special care needs | 68.2% | a | |
| Feeding | 5.7% | a | |
| Breathing | 32.1% | a | |
| Epilepsy | 43.1% | a | |
| Mobilization | 30.2% | a | |
| Impact of co-sleeping on child's sleep quality | |||
| Better | 52.3% | 40.8% | 0.038 |
| None | 40.7% | 52.2% | 0.041 |
| Worse | 7.0% | 7.0% | 0.999 |
| Impact of co-sleeping on father's sleep quality | |||
| Better | 3.9% | 2.7% | 0.515 |
| None | 46.1% | 53.1% | 0.235 |
| Worse | 50.0% | 44.2% | 0.329 |
| Impact of co-sleeping on mother's sleep quality | |||
| Better | 6.8% | 6.4% | 0.863 |
| None | 23.9% | 40.5% | 0.002 |
| Worse | 69.3% | 53.1% | 0.004 |
| Co-sleeping generates conflict | |||
| Between parents | 9.4% | 7.1% | 0.435 |
| Between parents and child | 11.2% | 10.8% | 0.908 |
| For parents at work | 11.0% | 1.3% | <0.001 |
| Parents disapprove co-sleeping | 20.7% | 25.3% | 0.342 |
- Bold indicates statistical significance (p<0.05). aNo information for children in the general population.
Table 4 summarizes the univariable (crude OR) and multivariable (adjusted OR) logistic regression analyses concerning co-sleeping in children with motor disabilities. For the univariable analyses, the only factor with a significant negative association toward co-sleeping was older age (group 14–18y, OR 0.21, 95% CI 0.10–0.45, p<0.001). For the factors with a significant positive association with co-sleeping, we found that pathological sleep (i.e. a SDSC total score ≥ T score 70) was the strongest factor (OR 4.03, 95% CI 2.05–7.89, p<0.001). The others were severe motor impairment (non-walker/GMFCS levels IV–V), drug resistant epilepsy defined by ongoing seizures despite two adequate antiepileptic drugs, severe/profound intellectual disability, severe visual impairment, tube feeding, and bilateral CP.15 In the multivariable logistic regression analysis the factors that were significantly associated with co-sleeping were age (14–18y, OR 0.11, 95% CI 0.04–0.31, p<0.001), housing crowding (OR 2.76, 95% CI 1.18–6.47, p=0.019), and pathological sleep (OR 5.07, 95% CI 2.04–12.57, p<0.001).
| Variables | Crude OR (95% CI) | p | Adjusted ORa (95% CI) | p |
|---|---|---|---|---|
| Age, y | ||||
| 4–8 | Baseline | Baseline | ||
| 9–13 | 0.62 (0.34–1.12) | 0.115 | 0.53 (0.25–1.12) | 0.096 |
| 14–18 | 0.21 (0.10–0.45) | <0.001 | 0.11 (0.04–0.31) | <0.001 |
| Sex (male) | 0.94 (0.56–1.58) | 0.811 | b | |
| Housing crowding | 1.79 (0.92–3.49) | 0.086 | 2.76 (1.18–6.47) | 0.019 |
| Parental unemployment | 1.18 (0.26–5.40) | 0.829 | b | |
| Parental educational level | 1.01 (0.92–1.11) | 0.805 | b | |
| Single parent household | 1.28 (0.63–2.36) | 0.558 | b | |
| Parental origin | ||||
| Both Swiss | Baseline | Baseline | ||
| Both from Europe | 1.49 (0.85–2.61) | 0.163 | 1.25 (0.60–2.59) | 0.551 |
| At least one not from Europe | 2.22 (0.84–5.88) | 0.108 | 1.79 (0.52–6.17) | 0.358 |
| Diagnostic category | ||||
| Cerebral palsy, unilateral | Baseline | Baseline | ||
| Cerebral palsy, bilateral | 2.63 (1.14–6.11) | 0.024 | 1.53 (0.52–4.76) | 0.420 |
| Neuromuscular diseases | 1.35 (0.44–4.14) | 0.597 | 1.32 (0.32–5.42) | 0.700 |
| Spinal/peripheral nerve diseases | 3.09 (0.89–10.8) | 0.077 | 3.40 (0.77–14.97) | 0.106 |
| Encephalopathies | 2.06 (0.79–5.38) | 0.139 | 0.73 (0.19–2.84) | 0.655 |
| Syndromes | 2.26 (0.97–5.23) | 0.058 | 1.16 (0.37–3.64) | 0.800 |
| GMFCS level | ||||
| Walker (GMFCS levels I–III) | Baseline | Baseline | ||
| Non-walker (GMCS levels IV–V) | 2.41 (1.34–4.33) | 0.003 | 1.74 (0.69–4.40) | 0.242 |
| Epilepsy | ||||
| None | Baseline | Baseline | ||
| Seizure control with ≤ two drugs | 1.49 (0.70–3.16) | 0.304 | 1.28 (0.42–3.85) | 0.666 |
| Drug resistant | 5.76 (2.31–14.37) | <0.001 | 2.90 (0.74–11.42) | 0.127 |
| Severe visual impairment | 2.93 (1.11–7.74) | 0.030 | 4.10 (1.00–16.86) | 0.051 |
| Intellectual disability | ||||
| None | Baseline | Baseline | ||
| Mild | 1.94 (0.90–4.15) | 0.089 | 2.57 (0.91–7.26) | 0.075 |
| Moderate | 1.07 (0.41–2.83) | 0.886 | 0.72 (0.20–2.62) | 0.623 |
| Severe/profound | 3.2 (1.67–6.14) | <0.001 | 1.52 (0.48–4.79) | 0.475 |
| Tube feeding | 3.12 (1.11–8.75) | 0.030 | 0.95 (0.23–3.94) | 0.940 |
| Night orthosis use | 1.64 (0.68–3.96) | 0.268 | b | |
| SDSC total score ≥T70 (based on our general population) | 4.03 (2.05–7.89) | <0.001 | 5.07 (2.04–12.57) | <0.001 |
- Bold indicates statistical significance (p<0.05). Hosmer–Lemeshow test (χ2=8.53; p=0.383). aAdjusted for age categories, crowding, parental origin, diagnostic categories, walker/non-walker, epilepsy severity, severe visual impairment, tube feeding, intellectual disability, pathological sleep (SDSC total score ≥ T70). bNot included in the multivariable logistic regression. OR, odds ratio; CI, confidence interval; GMFCS, Gross Motor Function Classification System; SDSC, Sleep Disturbance Scale for Children.
Discussion
Co-sleeping – whether occasional, weekly, or more often – was significantly higher among families of children with motor disability than in the general population. Co-sleeping per se among children with a motor disability or neurodevelopmental disorder has received little attention, as most studies have been dedicated to sleep quality and disorders. Even though the comparison is limited by the study not focusing on a single diagnosis, our rates of regular co-sleeping in the children with motor disability are similar to those reported in previous studies on CP and Duchenne muscular dystrophy.7, 9 In their study, Atmawidjaja et al.8 reported a rate of co-sleeping of about twice the rate we found in children with motor disabilities. Besides the different demographic and medical characteristics of their study population, the difference found in terms of co-sleeping rate and type may be related to the cultural and social aspects involved in how families handle sleep arrangements. These are known to influence co-sleeping throughout the world, co-sleeping being less prevalent in Western developed countries.3, 4, 16
Several factors were statistically associated with co-sleeping in children with motor disability. Co-sleeping decreased with increasing age. This observation matches the findings of other studies on healthy children from different cultures,6, 17 and most likely parallels both increasing child independence and the advance in sexual maturation and puberty. Housing crowding was positively associated with co-sleeping in the sample with motor disability, and this observation remained in the multivariable analysis. As more limited space at home leads to situations where several persons have to sleep in the same room, co-sleeping becomes an environmental necessity.
For medical factors, severe motor impairment, drug resistant epilepsy, severe visual impairment, severe intellectual disability, and tube feeding were all associated with co-sleeping in children with motor disability. These findings are concordant with those of previous studies.2, 7, 18-21 Severe visual impairment approached a significant association with co-sleeping in the multivariable logistic regression. This could be explained by the higher occurrence of sleep initiation problems, night awakenings, and need for physical contact to fall asleep in children affected by severe visual impairments.20, 22 Bilateral CP was significantly associated with co-sleeping, whereas other diagnostic categories of motor disabilities were not. It is noteworthy that all the previously mentioned comorbidities that are positively associated with co-sleeping often affect children with bilateral CP.
Two-thirds of the co-sleeping parents of children with motor disabilities reported that they resort to co-sleeping because they provide special care to their child at night. A third of the co-sleeping parents of children with motor disabilities feared an adverse event to their child at night, significantly more than for the sample from the general population. Almost 70% of mothers of children with motor disabilities reported a negative impact of co-sleeping on their own sleep quality, probably because of the demanding care and fears for their child at night. In comparison, a negative effect was reported for only half of the fathers. Considering that mothers completed more than 80% of the questionnaires, the impact of co-sleeping on fathers’ sleep quality may have been underestimated.
The positive association between the child's pathological sleep, as judged by the parents through the SDSC total score, and co-sleeping is complex to assess. Children affected by a motor disability have higher SDSC scores, meaning more pathological sleep than their healthy peers, problems in initiating and/or maintaining sleep being a common complaint. In this case co-sleeping would seem to be the result of pathological sleep, rather than the cause. It may also be possible that co-sleeping parents become more aware of their child's sleep disorders compared with parents sleeping in a separate room. In addition, co-sleeping may modify the child's sleep quality, either by disrupting it as noted by a greater number of arousals in healthy infants, or by improving it. In support of the latter hypothesis, more than 90% of co-sleeping parents of both children with motor disabilities and children from the general population reported a neutral or positive influence of co-sleeping on their child's sleep quality.
Our study had several limitations. A number of demographic factors differed significantly between our groups with motor disability and from the general population; however, calculations were made of adjusted prevalences for co-sleeping. We used the term ‘motor disability’ to encompass various neurological disorders, CP with its broad range of motor impairments and comorbidities, or some progressive diseases such as neuromuscular diseases. Even though each of these diseases may carry specific sleep-related issues or parental concerns, we chose to group these diagnoses as they all possess the potential to disrupt the sleep of the affected child and his/her family, sometimes independently of the perceived severity of the health condition. An important limitation of this study concerns comorbidities that were not addressed, such as autism spectrum disorder or attention-deficit–hyperactivity disorder. These are known to be more common in children with motor disabilities than in the general population, can alter the quality of sleep, and therefore may influence the practice of co-sleeping.1, 23, 24 Retrospective data collection, non-systematic behavioural and neuropsychological assessments, and confounding between moderate to profound intellectual disabilities and behavioural disorders did not allow us to confidently include these comorbidities, which were most likely underestimated in the medical files. Systematic information about chronic pain was not available for our sample with motor disabilities, although this factor can interfere with sleep quality.25 As is often the case in questionnaire-based studies, there could be a response bias as parents may feel reluctant to give information about their private sleeping habits and possible co-sleeping practice.
Conclusion
The presence of a motor disability induces co-sleeping, especially for more severe disabilities, and for those accompanied by comorbidities such as epilepsy or severe visual impairment. Parents of these children may have to provide care for their child at night, and/or have fears that something bad might happen in relation to their child's condition. Co-sleeping in these situations seems to have a negative impact on parental sleep; however, it may be that for some of these families sleeping separately may lead to worse parental sleep, and that co-sleeping is the best strategy to account for both the child's and the parents' needs for rest and sleep. Therefore, it is important to enquire about sleep and sleeping arrangements of the whole family to support them in their choices and provide respite when requested.
Acknowledgements
This study was supported by a grant from the Anna-Müller-Grocholski Foundation (Zurich, Switzerland). The Anna-Müller-Grocholski Foundation was not involved in the study design and conduct, in the analyses, or in the publication process. The authors have stated that they had no interests which may be perceived as posing a conflict or bias.
