Associations between self-reported upper limb motor ability, life satisfaction and life problems in people with cervical spinal cord injury from the community in the United States: a cross-sectional study

Abstract

Objective

This study aims to evaluate relationships between self-reported fine motor ability and quality of life (assessed by life satisfaction and life problems) from people with spinal cord injury (SCI) at T1 and above.

Study design

Observational cohort study (current analysis from a cross section)

Participants

279 individuals with SCI at T1 or above

Setting

Community members sampled from records from two Midwestern hospitals and a speciality hospital in the Southeast United States

Main outcome measures

Fine motor ability was assessed via the Spinal Cord Injury Functional Index-Short Form 9A, while two facets of quality of life, life satisfaction and life problems, were assessed by the Life Situation Questionnaire-Revised version (LSQ-R). Pearson correlations and multivariate analysis were utilised to identify cross-sectional relationships between fine motor ability, life satisfaction and life problems.

Results

Fine motor ability was positively correlated with total life satisfaction score (r=0.16; p=0.02) and was negatively correlated with the total life problems score (r=−0.18; p=0.01), health problems factor (r=−0.24; p<0.01), and social isolation factor (r=−0.27; <0.01). When controlling for age, sex, race/ethnicity and level of injury, better fine motor ability was significantly associated with greater life satisfaction (β=0.25; p=0.02), fewer life problems (β=−0.40; p<0.01), less social isolation (β=−0.11; p<0.01) and fewer health problems (β=−0.10; p<0.01).

Conclusion

The results identified significant, modest associations between self-reported outcomes, as better fine motor ability was related to less social isolation, fewer health problems and higher life satisfaction. Further investigation into the relationship between fine motor ability, life satisfaction and life problems is warranted.

STRENGTHS AND LIMITATIONS OF THIS STUDY.

• The association between UL motor ability and quality of life among people with tetraplegia has long been assumed but has not been assessed in a sample of this size (n=279).

• The presented data are self-reported, and self-reported data are typically associated with some unintentional errors in responding. Any such measurement error would have resulted in artificially lowering the observed correlations.

• This is an observational study which is necessary to lay the foundation for future studies. Although it will not directly lead to changes in practice to improve outcomes, it has identified associations that may inform future research hypotheses towards assessing causal and longitudinal relationships.

Introduction

Approximately 300 000 people are living with spinal cord injury (SCI) in the United States, and about half of these injuries occur at the cervical level resulting in tetraplegia.¹ Tetraplegia is characterised by reduced motor control and sensory function below the level of injury, often involving the trunk, upper limbs (UL) and lower limbs, leading to variable levels of physical impairment. People with tetraplegia rate restoring UL motor ability as a high priority, over other components of recovery such as standing or bowel and bladder control.^{2 3} These previous studies suggest that UL motor ability is important to people with tetraplegia and may contribute to perceived quality of life in this population. However, the cross-sectional relationship between UL fine motor ability and quality of life has yet to be established in people with tetraplegia due to cervical SCI.

Indirect links between UL motor ability and quality of life are supported in the literature. For example, the associations between (1) motor ability and activity independence and (2) activity independence and quality of life are well established. Better UL motor ability is associated with greater independence in activities of daily living like bathing, dressing, transfers and other self-care tasks (eg, catheterization).⁴,⁹ Longitudinal studies further demonstrate this positive relationship, where those that recovered UL movement showed greater functional independence.^{10 11} Since activity independence is positively associated with quality of life,^{12 13} it stands to reason that individuals with better UL motor ability might report higher quality of life; however, this remains an assumption, since no studies have established this association.

Other evidence suggesting a relationship between UL motor ability and quality of life comes from rehabilitation intervention studies. Interventions targeting UL motor recovery have coincided with secondary gains in quality of life in some reports,^{14 15} whereas other studies report motor improvements without concomitant changes in quality of life.^{16 17} While this evidence suggests potential for a causal relationship, the mix of results¹⁴,¹⁷ suggests the relationship may be tenuous or dependent on characteristics of the individual studies (ie, the amount of UL motor improvement induced by the intervention or the scale selected to assess quality of life). Without basic observational studies, it can be difficult to generate research or clinical hypotheses around causal or longitudinal relationships. By establishing the cross-sectional relationships, we aim to add to the framework for clinicians and researchers who are intervening at the level of the motor system with a secondary goal of improving overall quality of life, as is common in both clinic and research settings.

According to the WHO, quality of life refers to an individual’s perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards and concerns. While there are many tools for assessing an individual’s quality of life, subjective reporting about well-being, including reporting of life satisfaction and life problems, is a key component of quality of life. As the definition implies, many variables have been shown to contribute to quality of life, including social support, secondary conditions like pain or depression, employment status, individual characteristics like self-efficacy, handicap and functional independence.¹⁸,²² Consistent with the WHO definition and prior work, quality of life reflects the cumulative contribution of multiple factors rather than being governed by a single variable.

Given that previous work has not explicitly defined the cross-sectional relationship between self-reported UL motor ability and quality of life in people with cervical SCI, the current study aims to assess this relationship from data from a 45 year longitudinal study of SCI that contained both variables of interest: UL motor ability and quality of life. A survey of UL motor ability was added in the 2018–2019 cohort, which assessed the individual’s perspective of their movement abilities across the entirety of their daily lives, reflecting a distinct and meaningful component of motor ability and recovery. The other primary assessment tool, the Life Satisfaction Questionnaire, measured two facets of quality of life: life satisfaction and self-reported problems. We hypothesised that better fine motor ability would be associated with fewer self-reported problems and higher overall life satisfaction but that the relationships would be modest overall. We also evaluated associations between fine motor ability and the factors within life satisfaction (home life, vocational and global) and life problems (health problems, environmental barriers, emotional distress, social isolation, lack of opportunities and money problems) to inform future research.

Methods

Selection and description of participants

During the original study recruitment, participants were identified through outpatient records from two Midwestern hospitals (University of Minnesota Medical Center and Courage Kenny Rehabilitation Institute, formerly Sister Kenny Rehabilitation Institute) and a speciality hospital in the Southeast (Shepherd Center). Inclusion criteria at enrollment encompassed individuals with the following: (1) traumatic SCI, (2) age of 18 years or older, (3) a minimum of 1 year post-injury and (4) enduring residual effects of their SCI. These individuals were initially enrolled in a longitudinal SCI study that commenced in 1973, with new cohorts added in 1984, 1993 and 2003.²³,³⁰ For the current analysis, we utilised the most recent data available, gathered between 2018 and 2019 (n=557). After eliminating those who were deceased since the last follow-up (n=126), materials were sent to 642 potential participants, of which 557 responded (86.8%). This cohort was the first to include the survey of fine motor ability and, therefore, the only available dataset with this variable. Given the focus of our research question, which was to understand relationships between UL motor ability and quality of life in people with cervical SCI, we excluded 278 participants with injury levels below T1 (according to self-report), resulting in a final sample size of 279. However, due to incomplete responses from participants, not all items could be scored. Total available sample for each analysis is provided in Supplementary Materials (online supplemental Table S1) and varied from n=199 to n=256. UL muscles are innervated by spinal levels T1 and above; therefore, we included those with injuries to cervical segments T1 and above, whose injuries would have direct influence on the descending control of the UL muscles.

Data collection and measurements

Institutional review board approval was obtained from the Medical University of South Carolina’s Institutional Review Board for Human Subjects Research (reference number Pro00060766) prior to conducting the study. Participants received an introductory letter outlining the study’s purpose, along with a notice that materials would be dispatched within 4 to 6 weeks. They were also provided with a link to submit their materials online using Redcap. These materials comprised a cover letter containing all components of informed consent, as well as the study questionnaire. Completion of materials was considered implied consent. Individuals who did not respond received two additional mailings, supplemented by a follow-up phone call. Participants were offered a remuneration of $50 for the returned questionnaire.

The primary study outcome was quality of life as measured by the Life Situation Questionnaire-Revised version (LSQ-R).^{31 32} This self-report instrument assesses two aspects of quality of life: life satisfaction (20 items) and life problems (30 items). All items were evaluated using a 5-point Likert scale. Specifically, for the life satisfaction items, a score of 1 indicated ‘very dissatisfied’, while a score of 5 denoted ‘very satisfied’. For the problem items, a score of 1 represented ‘no problem’, and a score of 5 signified a ‘major problem’. The LSQ-R has undergone validation and factor analysis, including separate factor analysis of the set of 20 satisfaction items and the 30 problems items. Within this structure, there are three life satisfaction subscales, encompassing home life satisfaction (four items related to family, living circumstances and relationship status), vocational satisfaction (three items concerning employment, financial means and job opportunities) and global satisfaction (11 items concerning general life, emotions, health and recreation). Additionally, there are six life problem subscales, including health problems (six items concerning pain, skin sores, spasticity, sweat and urinary tract infections), social isolation (five items related to loneliness, lack of control, boredom, dependency and difficulty making new friends), emotional distress (five items focusing on emotional pain, stress, worries, sadness and depression), environmental barriers (three items addressing negative attitudes toward the disabled and lack of accessibility), money problems (three items concerning inadequate income and employment) and lack of opportunities (three items related to insufficient job skills and learning opportunities). Further details regarding the nine-subscale structure and factor analysis can be found elsewhere.^{33 34}

Fine motor ability was measured by nine items from the Spinal Cord Injury Functional Index (SCI-FI)-Short Form subscale 9A.^{35 36} As opposed to assessments of gross UL motor ability, fine motor ability assessment can capture meaningful variability across the whole cervical SCI population, even those with injuries at lower cervical segments (C8 to T1) where most proximal UL muscles are spared, and the muscles of the wrist and hand are affected. Fine motor ability, with respect to the SCI-FI and the current study’s operational definition, is ‘the ability to manually hold, manipulate and move objects requiring varying degrees of dexterity and/or strength’. For each item on the SCI-FI Fine Motor Ability subscale, participants are asked to report the amount of difficulty they have doing the activity without any devices, special equipment or help from another person: a score of 1 suggested ‘unable to do’, while a score of 5 indicated ‘without any difficulty’. Self-reported fine motor ability is a distinct and meaningful component of motor ability and recovery that can be efficiently measured in large samples. By assessing the participant’s perspective of their movement, we may gain understanding of the participant’s own experience across the entirety of their daily lives (rather than a single time of day under a single condition or setup as in most standardised clinical assessments). In this way, self-report measures can offer insight into mobility that might otherwise be difficult to measure, such as that which occurs through the cycle of the day and in life outside of a research lab.

Patient and public involvement

Individuals with SCI and members of the community were involved in the study design and conduct of the study through advisory panels. Panel members convened, reviewed and provided feedback on the study methodology including assessment of participant burden. General findings from the study are disseminated to participants through routine newsletters.

Statistical analyses

All statistical analyses were performed in SAS version 9.3 (SAS Institute, Inc., Cary, NC). We first provided descriptive statistics for all variables. To address our primary hypothesis that fine motor ability would be related to quality of life, we assessed the relationship between fine motor ability and life satisfaction total score and life problems total score using Pearson correlation coefficients and multivariate analysis using ordinary least square (OLS) regression models.

To model the relationships between the three life satisfaction subscale scores and the six life problem subscale scores, we first assessed Pearson correlation coefficients. Where the correlations were significant (p<0.05) and the r values suggested at least close to moderate relationships, we performed multivariate analysis using OLS regression models. In all OLS models, SCI-FI fine motor ability score was the primary independent variable. Four additional covariates were considered in our regression models because of their potential to explain variance in quality of life: age, sex (male vs female), race/ethnicity (non-Hispanic White vs others) and injury level (C1–4 injury level vs others; determined from self-report on survey). Utilising C1-4 to denote high cervical injuries is common practice in the field of SCI and is often used as a covariate to control for injury severity or impairment severity.¹⁰³⁷,⁴⁰

Results

Study participants averaged 57 years of age (SD=11) with 73% male, 77% non-Hispanic White and 31% cervical 1–4 injury (table 1). The Pearson correlation coefficients indicated that fine motor ability had a small, significant positive association with the life satisfaction total score (r=0.16; p=0.02), vocational subscale score (r=0.15; p=0.02) and global subscale score (r=0.14; p=0.03) (table 2). The Pearson correlation coefficients indicated that fine motor ability had significant negative association with the life problem total score (r=−0.18; p=0.01), health problem subscale score (r=−0.24; p<0.01) and social isolation subscale score (r=−0.27; p<0.01) (table 2; online supplemental Table S1 for CIs).

Table 1. Characteristics of the study sample population.

Descriptor	Value (max score, where applicable)
LSQ-R Life Satisfaction Total Score	70±17 (100)
LSQ-R Life Problem Total Score	60±23 (150)
SCI-FI Fine Motor Ability Score	30±12 (45)
Age (years)	57±11
Male (n, %)	203, 73%
Non-Hispanic White (n, %)	214, 77%
Individuals with cervical 1–4 level injury (n, %)	86, 31%

Mean±SD.

LSQ-R, Life Satisfaction Questionnaire revised version; SCI-FI, Spinal Cord Injury Functional Index.

Table 2. Pearson correlation coefficients between SCI-FI Fine Motor Ability Score and LSQ-R Scores.

	R	P value
Life satisfaction total	0.16	0.02
Factor score
Home life	0.07	0.27
Vocational	0.15	0.02
Global	0.14	0.03
Life problems total	−0.18	0.01
Factor score
Health problems	−0.24	<0.01
Environmental barriers	0.01	0.84
Emotional distress	−0.06	0.32
Social isolation	−0.27	<0.01
Lack of opportunities	−0.12	0.05
Money problems	−0.01	0.85

LSQ-R, Life Satisfaction Questionnaire revised version; SCI-FI, Spinal Cord Injury Functional Index.

In multivariate models, while controlling for age, sex, race/ethnicity and injury level (determined by self-report on survey), we found better fine motor ability was significantly associated with higher life satisfaction total score (β=0.25; p=0.02) and lower life problem total score (β=−0.40; p<0.01). Fine motor ability was also negatively associated with health problems subscale score (β=−0.10; p<0.01) and social isolation subscale score (β=−0.11; p<0.01) (table 3; online supplemental Table S2) for CIs). The covariates of age, sex (male), race/ethnicity (non-Hispanic White) and injury level (C1-4 injury level) were not significant in any of the regression models.

Table 3. Ordinary least squares regression models for relationships between life satisfaction, life problems and fine motor ability.

	LSQ-R total score				Problems factor score
	Satisfaction		Problems		Health problems		Social isolation
	β	Sig.	β	Sig.	β	Sig.	β	Sig.
Intercept	53.22	<0.01	86.51	<0.01	16.51	<0.01	15.04	<0.01
Age	0.13	0.26	−0.21	0.23	0.00	0.96	−0.02	0.54
Male	−0.60	0.82	2.24	0.55	0.54	0.47	0.45	0.52
Non-Hispanic White	2.78	0.37	−4.77	0.27	−0.80	0.35	−0.26	0.74
Injury level C1-4	4.32	0.11	−3.65	0.34	0.46	0.53	−0.45	0.51
SCI-FI Fine Motor Ability	0.25	0.02	−0.40	<0.01	−0.10	<0.01	−0.11	<0.01

C1−4, cervical spinal levels 1–4; LSQ-R, Life Satisfaction Questionnaire revised version; SCI-FI, Spinal Cord Injury Functional Index; Sig, significance represented by p-value.

We also assessed the normality of all outcome variables and found that the life satisfaction total score was slightly left-skewed, whereas the life problems total score, health problems subscale score and isolation subscale score were slightly right-skewed. To address these deviations, we conducted log transformations for all four outcome variables to improve normality. The log-transformed analyses resulted in only minor changes to the p-values and did not alter the conclusions. Given the minimal impact on results and to facilitate more straightforward interpretation, we elected to report the untransformed results. The log-transformed analyses results are available on request.

Discussion

The unique contribution of this work is the identification of modest but significant relationships between fine motor ability and quality of life measured by self-report of life satisfaction and life problems. Better self-reported fine motor ability was associated with higher life satisfaction and fewer self-reported life problems, specifically less social isolation and fewer health problems (eg, urinary tract infections, pressure ulcers) in a cross-sectional sample (n=279) of people with SCI at or above T1. These relationships were significant while controlling for important demographic and injury characteristics, such as injury level, sex and race. This work establishes the fundamental cross-sectional relationships between fine motor ability and two facets of quality of life (life satisfaction and life problems) that can inform clinicians and researchers in future work assessing longitudinal relationships and the potential for causal relationships. The current results inform future study but cannot provide any evidence of a causal relationship between fine motor ability and quality of life.

While the significant correlations reported in the current study represent modest relationships (r=0.14–0.27), the magnitude of these correlations is not unexpected in the context of previous work. A meta-analysis from 1997 found that the average correlation between impairment (r=−0.05, non-significant), disability (r=−0.21, significant), and handicap (r=−0.28, significant) was small to moderate, where some components of handicap, such as formal social integration (r=−0.41), showed stronger relationships.²⁰ The correlations that we identified are mostly comparable with this meta-analysis as well as with more recent studies that assessed relationships between quality of life and motor-related variables: for handicap, correlations ranged from 0.16 to 0.42^{41 42} and for functional independence, correlations ranged from close to zero and non-significant to 0.72, depending on the scales utilised, where most correlations were significant and in the small to moderate range.¹³⁴¹,⁴⁴ Considering the multifaceted nature of quality of life, it is not surprising that no single variable demonstrates large correlations. Multivariate models explain about 13–66% of variance in quality of life,^{12 22 41 42 45 46} where strongest models include a combination of many variables related to physical/motor function, secondary health conditions like pain or depression, social support and/or individual qualities like self-efficacy, suggesting that no single variable explains a large portion of quality of life. Our modest correlations and the insignificant relationships of covariates in the regression model highlight the same idea: quality of life is a complex representation of the individual’s characteristics, situation and environment such that no single variable explains a large portion of quality of life.

Previous studies assessed relationships between life satisfaction and variables related to the motor system, like neurologic impairment and injury severity.^{12 46 47} Completeness of injury does not demonstrate a strong relationship with quality of life, especially when other factors, like independence, are included in the model. Level of injury, when considered as tetraplegia vs paraplegia, significantly relates to quality of life, where tetraplegia is associated with reduced quality of life.^{46 48} However, when considering the neurologic level of injury at a segmental level, rather than broad dichotomous classification, the correlation with quality of life is small (r=0.07).⁴² Similar to completeness, the relationship between level of injury becomes non-significant once other variables, like presence of depression or activity independence, are considered.^{42 45} Taken together, this suggests that the neurologic impairment itself is not a key driver of quality of life; rather, the downstream effects of the primary neurologic damage are more likely to contribute to overall quality of life. This could be because completeness or neurologic level of injury cannot fully account for unique aspects of the neurologic injury and recovery process that dictate the resulting presentation, including the motor presentation. On the other hand, variables like activity independence or fine motor ability may be better reflections of the total underlying neurologic damage and recovery process.

Other studies have investigated how motor-related variables, like activity independence^{12 49 50} or handicap,^{41 42} relate to quality of life. While related to motor ability, handicap and independence represent distinct constructs. For example, mobility handicap, as measured by the Craig Handicap Inventory, quantifies days out of the house, nights away from home, number of hours out of bed, transportation, entering and exiting home with/without assistance, and independent access to home.⁵¹ Because it is non-specific to UL motor abilities, it may be more representative of other aspects of motor ability like trunk and lower limb motor function, limiting its applicability to those with tetraplegia and impaired arm and hand function. Likewise, activity independence, measured by the Functional Independence Measure (FIM) or Spinal Cord Independence Measure (SCIM), assesses the amount of assistance required to complete a functional task, like bathing or dressing,^{52 53} not how fine motor ability contributes to the completion of an activity. While these variables are sometimes implicitly equated to motor function or ability, they are separate constructs not intended to capture varying degrees of grasp and grip ability. The SCI-FI Fine Motor – Short Form 9A was specifically designed to assess tasks that depend on fine motor ability like holding a book, picking up a coin and turning a doorknob. As such, measurement tools like the SCI-FI Fine Motor subscale, that can specifically assess meaningful variability of UL motor ability, may be more useful measures to include in studies assessing the motor system contributions to quality of life in people with cervical SCI.

Future longitudinal research is needed based on the current study findings. Before conducting longitudinal research, it is necessary to first establish a cross-sectional model to demonstrate the relationships between key variables (in this case, fine motor ability, life satisfaction and life problems). In the absence of cross-sectional models, it is difficult to know whether there are significant relationships between key variables, much less a pattern that might reflect changes over time. Despite this, clinical trials testing UL motor interventions commonly measure quality of life as a secondary outcome alongside primary motor-related variables. Given that many variables contribute to quality of life in people with SCI^{22 45 51} and the modest associations identified by the current study, future hypothesis-driven research may not expect that intervening to improve UL motor ability alone will produce large improvements in quality of life; however, this does not imply that small improvements in either variable are or are not clinically meaningful. In addition, future intervention studies examining quality of life as an outcome should consider the selection of quality of life assessment tool given the multitude of available options. Considering the current study identified the strongest relationships with life problems, specifically social isolation and health problems, a measure that assesses these variables may be most responsive to changes in UL fine motor ability if a causal relationship exists.

There were several methodological considerations when interpreting the results of the study. First, although the magnitude of the observed relationships is relatively modest, it is important to note that the range of observations was restricted due to the elimination of all those with T2 injuries and below. This was appropriate for an analysis of UL, but a restriction in the range reduces the magnitude of associations. Second, although part of a longitudinal study, the data utilised were cross-sectional as the measure of the UL was only recently developed. Inclusion of new measures is a strength of longitudinal studies; however, the longitudinal data is not yet available. When available, it will allow us to test the stability of the observed relationships with longitudinal data. Third, the data are self-report. As both the dependent and independent variables are obtained from the same source using the same measurement method, shared-method variance may exist and could potentially influence the observed relationship between motor ability and quality of life. Fourth, in the data analysis, the percentage of missing values varied (response rates varied from 71% and 92% across items). It is possible that the missing responses were not at random, but it is hard to determine the bias direction based on the current data collected. Lastly, the findings do not speak to clinical significance. This is an observational study which is necessary to lay the foundation for future studies. Therefore, although it will not directly lead to changes in practice to improve outcomes, it has identified associations that may become the focus of future studies. Regarding external validity, the sample population included only those with injury above T2. As compared with the statistics presented in the Traumatic Spinal Cord Injury Facts and Figures at a Glance: 2025 SCI Datasheet presented by the National Spinal Cord Injury Statistical Centre (SCI Model System), the current sample was more white (77% in the current study vs 55%) and comparable in gender (73% male in the current study vs 78% of new traumatic SCI since 2015). Our sample is likely representative of limited geographic regions (sample derived from hospitals in the Midwestern and Southeastern United States) and is less ethnically diverse than the overall SCI population in the United States, which should be considered as a limitation of overall generalisability.

Our results should be interpreted as correlational and not causal. Future studies may aim to identify causal relationships and explore how differences in the UL motor ability relate to the better outcomes observed in this study. The intricacies of these relationships can be more fully understood through investigation of the mechanisms through which UL motor ability might be supporting quality of life. For example, we did not include measures of activity independence which could act as a mediator or moderator on the path between motor ability and life satisfaction/health problems. Future studies may incorporate more comprehensive measures to clarify mechanisms linking motor ability to quality of life and health problems. Future studies would also benefit from more objective information about isolation, health problems and other factors. The current study used self-report methods for quantifying fine motor ability. Self-report is widely used to monitor health, morbidity and mortality by the Centres for Disease Control and Prevention and, more specifically, within the SCI Model Systems. However, future research would contribute additional knowledge by using objective, standardised assessment of UL motor ability. Ultimately, intervention studies are needed to not only identify how to effectively improve UL motor ability, but also to identify the extent of associated improvements on quality-of-life and health. It is only through multiple types of designs that we will be able to fully translate findings regarding associations between UL and important SCI outcomes into enhanced outcomes to improve the lives of those with SCI.

Conclusions

The current study indicates that self-reported fine motor ability is modestly associated with life satisfaction and life problems, including self-reported health problems and social isolation, in people with SCI at or above T1. Better fine motor ability was associated with greater life satisfaction and fewer life problems. This initial study provides evidence for significant, but modest relationships between fine motor ability and quality of life that should be investigated further to define longitudinal and causal relationships.

Data availability statement

Data are available upon reasonable request.