Relationship Between Body-Specific Attention to a Paretic Limb and Real-World Arm Use in Stroke Patients: A Longitudinal Study

 

I happen to think your definition of learned non-use is completely wrong.  It is vastly more likely that  the neuronal cascade of death in the first week is the problem. You may be able to initially move a muscle but after the neuronal cascade of death has occurred, you no longer have live brain cells that can do that task.  You are assigning learned non-use to an impossibility and blaming the patient rather than BLAMING THE DOCTOR for not stopping the neuronal cascade of death. 

My take is that your doctor has the learned nonuse problem, they have learned to do nothing for stroke survivors and have been getting away with it for decades. 

Relationship Between Body-Specific Attention to a Paretic Limb and Real-World Arm Use in Stroke Patients: A Longitudinal Study

 

Ryoji Otaki^1,2, Yutaka Oouchida^1,3, Naoki Aizu^1,4, Tamami Sudo^1,5, Hiroshi Sasahara², Yuki Saito⁶, Sunao Takemura⁶ and Shin-Ichi Izumi^1,7*

• ¹Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan
• ²Department of Rehabilitation, Yamagata Saisei Hospital, Yamagata, Japan
• ³Department of Education, Osaka Kyoiku University, Osaka, Japan
• ⁴Faculty of Rehabilitation, School of Health Sciences, Fujita Health University, Toyoake, Japan
• ⁵Department of Computer and Information Sciences, Tokyo University of Agriculture and Technology, Tokyo, Japan
• ⁶Department of Neurosurgery, Yamagata Saisei Hospital, Yamagata, Japan
• ⁷Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan

Learned nonuse is a major problem in upper limb (UL) rehabilitation after stroke. Among the various factors that contribute to learned nonuse, recent studies have focused on body representation of the paretic limb in the brain. We previously developed a method to measure body-specific attention, as a marker of body representation of the paretic limb and revealed a decline in body-specific attention to the paretic limb in chronic stroke patients by a cross-sectional study. However, longitudinal changes in body-specific attention and paretic arm use in daily life (real-world arm use) from the onset to the chronic phase, and their relationship, remain unknown. Here, in a longitudinal, prospective, observational study, we sought to elucidate the longitudinal changes in body-specific attention to the paretic limb and real-world arm use, and their relationship, by using accelerometers and psychophysical methods, respectively, in 25 patients with subacute stroke. Measurements were taken at baseline (T_BL), 2 weeks (T_2w), 1 month (T_1M), 2 months (T_2M), and 6 months (T_6M) after enrollment. UL function was measured using the Fugl-Meyer Assessment (FMA) and Action Research Arm Test (ARAT). Real-world arm use was measured using accelerometers on both wrists. Body-specific attention was measured using a visual detection task. The UL function and real-world arm use improved up to T_6M. Longitudinal changes in body-specific attention were most remarkable at T_1M. Changes in body-specific attention up to T_1M correlated positively with changes in real-world arm use up to T_6M, and from T_1M to T_6M, and the latter more strongly correlated with changes in real-world arm use. Changes in real-world arm use up to T_2M correlated positively with changes in FMA up to T_2M and T_6M. No correlation was found between body-specific attention and FMA scores. Thus, these results suggest that improved body-specific attention to the paretic limb during the early phase contributes to increasing long-term real-world arm use and that increased real-world use is associated with the recovery of UL function. Our results may contribute to the development of rehabilitation strategies to enhance adaptive changes in body representation in the brain and increase real-world arm use after stroke.

Introduction

The most common disability after stroke is upper limb (UL) paralysis, which occurs contralateral to a unilateral hemispheric injury. More than 80% of stroke patients experience this condition in the acute phase, and more than 40% of these patients have a residual disability in the chronic phase (Gresham et al., 1995). With the recent developments in acute stroke treatment, it has been reported that the percentage of patients with UL motor impairment within 72 h after stroke onset has decreased; however, 48% of stroke patients still had UL motor impairment (Alt Murphy et al., 2011; Persson et al., 2012). UL paralysis affects activities of daily living and reduces the quality of life (Nichols-Larsen et al., 2005). Many stroke patients with UL paralysis will stop using their paretic hand to avoid failure or inconvenience. Once the patient becomes accustomed to using the non-paretic hand, attempts to use the paretic hand are further reduced, resulting in learned nonuse, which is a major clinical problem (Taub et al., 2002). Learned nonuse leads to progressively smaller cortical areas representing the paretic limbs of the brain due to use-dependent neuroplasticity. These secondary changes in the neural system can worsen the motor impairment of the paretic limb. This negative cycle caused by learned nonuse prevents the recovery of the paretic limb after a stroke. For these reasons, in recent rehabilitation medicine, active use of the paretic limb is recommended to overcome and prevent learned nonuse (Morris et al., 2006).

Since the concept of learned nonuse was proposed, the importance of using the paretic hand in daily life (real-world arm use) as well as in function has been emphasized in the rehabilitation of stroke patients (Hebert et al., 2016; Winstein et al., 2016; Kelly et al., 2018). Accelerometers have been widely used as a method to measure real-world arm use objectively (Uswatte et al., 2000, 2005a). Early studies using accelerometers focused on stroke patients in the chronic phase (Uswatte et al., 2000, 2005a), but later cross-sectional studies investigated the acute phase (Gebruers et al., 2008) and the subacute phase (Thrane et al., 2011; Alt Murphy et al., 2019) of stroke. These studies using accelerometers from the acute to the chronic phase after stroke have been conducted and established an objective method to measure real-world arm use after stroke (Noorkoiv et al., 2014). Using accelerometers, several studies have reported factors associated with paretic hand use in patients with stroke. Although it has been thought that improvements in UL function translate directly to increased arm use in daily life, evidence from recent research, in which daily life arm use was evaluated using accelerometry, did not support this notion (Rand and Eng, 2012, 2015; Waddell et al., 2017). Instead, these studies indicated that, while UL function and arm use in daily life are related, they are distinctly different constructs. Specifically, it has been recognized that there is a disparity between UL function and real-world arm use (Rand and Eng, 2012). Despite improvements in UL function with inpatient rehabilitation after stroke, the use of the paretic hand did not improve significantly, and the use ratio of the paretic hand to the non-paretic hand was only 25%. Furthermore, when the effect of whether the paretic hand was dominant in real-world arm use was examined, no significant effect was found (Rand and Eng, 2012). In addition, this discrepancy between improved UL function and increased real-world arm use is known to occur even after hospital discharge (Rand and Eng, 2015; Doman et al., 2016). A comparison of paretic hand use at discharge to home and 12 months post-stroke showed that, despite significant improvement in UL function, there was no significant improvement in the use of the paretic hand in daily life. The use ratio of the paretic hand to the non-paretic hand at 12 months after stroke was 35%, which was very limited (Rand and Eng, 2015). These findings suggest that there is a discrepancy between improvement in UL function and real-world arm use and that factors other than function may also influence real-world arm use. Other studies have examined the impact of individual factors, including psychosocial factors and function, on real-world arm use. Observations up to 12 weeks after onset showed that real-world arm use increased, but that psychosocial factors (belief and confidence in UL performance, and motivation for UL use) had no effect on real-world arm use (Waddell et al., 2019a). A study of the psychosocial factors up to 6 months post-onset found that beliefs, confidence, and motivation regarding UL use remained high up to 6 months post-stroke, there was no correlation between psychosocial factors and clinical outcomes (Waddell et al., 2019b). Although these studies on real-world arm use have examined functional and psychosocial factors, the factors that influence the recovery of real-world arm use remain unclear.

In recent years, among the various factors that contribute to learned nonuse, many studies have focused on body consciousness, including body representation in the brain (Aymerich-Franch and Ganesh, 2016; Naito et al., 2016; Oouchida et al., 2016; Matamala-Gomez et al., 2020). Body consciousness is the consciousness of one’s own body, which has been discussed in philosophy and phenomenology. When body consciousness changes after a stroke, stroke patients relate the consciousness that “I feel as if it is not my hand” about the paretic limb. This body consciousness is broadly classified by Gallagher into “sense of body ownership” and “sense of agency” (Gallagher, 2000). In the hierarchy of body consciousness, sensorimotor representation is the lowest level. Sensorimotor representation is the body consciousness that is integrated by sensory and predictive information. This is the body representation in the brain that has been studied in the fields of psychology and medicine in recent years. Human movements are planned and executed based on this body representation in the brain.

In stroke patients, in addition to the paralysis caused by the brain injury, maladaptive changes in body representation of the paretic limb in the brain may prevent the use of the paretic limb in daily life. If the brain does not recognize the paretic hand as “my hand,” it may be difficult to use the paretic hand spontaneously in daily life. Body consciousness, including body representation of the limb in the brain, could not be observed externally. Thus, a method, using a visual detection task, has been developed to measure the amount of body-specific attention, i.e., attention specifically directed at the body (Aizu et al., 2018). In the above method, based on the body facilitation effect of visual detection of the self (Hari and Jousmäki, 1996; Whiteley et al., 2004, 2008; Reed et al., 2006, 2010; Tseng et al., 2012), the difference between the reaction time to a visual target outside the body and the reaction time to visual target on the body is defined as body-specific attention. This facilitation effect has been reported to occur even when the hand is not visible (Reed et al., 2006), and by attributing the hand to oneself (Whiteley et al., 2008). These studies support the idea that body representations in the brain facilitate the detection of visual information. In chronic stroke patients, it has been reported that, the more severe the hemiparesis and the longer the duration of the stroke, the lower is the body-specific attention (the facilitation effect did not occur in the paretic hand; Aizu et al., 2018). The results suggested that maladaptive changes in the body representation of the paretic hand in the brain occurred due to learned nonuse in chronic stroke patients. However, although the relationship between body-specific attention and UL function in cross-sectional studies of chronic stroke patients has been clarified, the longitudinal changes in body-specific attention and real-world arm use from stroke onset to the chronic phase, and the relationship between them, are unclear.

We hypothesized that improvements in body-specific attention to the paretic hand may facilitate real-world arm use. Since the previous study made it possible to measure learned nonuse from the aspect of body representation quantitatively, it may be possible to clarify how learned nonuse of the paretic limb progresses after the onset of stroke from the perspective of body representation in the brain and behavior of stroke patients, by using a visual detection task and accelerometer.

Therefore, this study aimed to elucidate the longitudinal changes in body-specific attention to the paretic limb and real-world arm use, and the relationship between them, by using accelerometers and psychophysical methods, respectively, in subacute stroke patients. This is expected to clarify the adaptive mechanisms underlying UL recovery after stroke from the perspective of behavior and body representation of the paretic limb in the brain.

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