Motor Lateralization Provides a Foundation for Predicting and Treating Non-paretic Arm Motor Deficits in Stroke

Abstract

Brain lateralization is a ubiquitous feature of neural organization across the vertebrate spectrum. We have developed a model of motor lateralization that attributes different motor control processes to each cerebral hemisphere. This bilateral hemispheric model of motor control has successfully predicted hemisphere-specific motor control and motor learning deficits in the ipsilesional, or non-paretic, arm of patients with unilateral stroke. We now show across large number and range of stroke patients that these motor performance deficits in the non-paretic arm of stroke patients vary with both the side of the lesion, as well as with the severity of contralesional impairment. This last point can be functionally devastating for patients with severe contralesional paresis because for these individuals, performance of upper extremity activities of daily living depends primarily and often exclusively on ipsilesional arm function. We present a pilot study focused on improving the speed and coordination of ipsilesional arm function in a convenience sample of three stroke patients with severe contralesional impairment. Over a three-week period, patients received a total of nine 1.5 h sessions of training that included intense practice of virtual reality and real-life tasks. Our results indicated substantial improvements in ipsilesional arm movement kinematics, functional performance, and that these improvements carried over to improve functional independence. In addition, the contralesional arm improved in our measure of contralesional impairment, which was likely due to improved participation in activities of daily living. We discuss of our findings for physical rehabilitation.

Hindlimb motor responses to unilateral brain injury: spinal cord encoding and left-right asymmetry

“…‘Postural instability’ is significantly more frequent among patients with right-hemisphere lesions, while ‘apraxic responses’ predominate among those with left-hemisphere injury ( Spinazzola et al , 2003 ). Consistently, animal studies showed that changes in locomotor behaviour and correlated region-specific differences in turnover of neurotransmitters after somatosensory TBI were dependent on the side of brain injury ( Robinson, 1979 ; Pearlson and Robinson, 1981 ; Spinazzola et al , 2003 ; Perennou et al , 2008 ; Sainburg, 2014 ; Sainburg et al , 2016 ; Ocklenburg et al , 2017 ; Fernandes et al , 2018 ; Stancher et al , 2018 ). Right but not left somatosensory lesions produced behavioural hyperactivity and bilaterally decreased cerebral and locus ceruleus norepinephrine concentrations.…”

Laterality of Damage Influences the Relationship Between Impairment and Arm Use After Stroke

“…Unfortunately, almost all these prior studies have ignored the impact of the hemisphere of brain damage on the relationship between clinical impairment measures and arm use patterns. This is despite growing evidence that damage to the left or right hemisphere produces distinct behavioral deficits (Mani et al, 2013;Schaefer, Haaland, & Sainburg, 2009;Schaefer, Mutha, Haaland, & Sainburg, 2012;Winstein & Pohl, 1995), and that these differential deficits hold significant implications for rehabilitation (Sainburg, & Duff, 2006;Sainburg, Maenza, Winstein, & Good, 2016). For example, a large body of work has shown that motor control (Haaland, Prestopnik, Knight & Lee, 2004;Mani et al, 2013;Schaefer et al, 2009;Winstein & Pohl, 1995), error correction (Schaefer et al, 2012) and learning (Garry, Kamel & Nordstrom, 2004;Mutha, Sainburg, & Haaland, 2011a,b) are all differentially affected in patients with left versus right hemisphere damage when they are tested on point-to-point reaching movements.…”

Learning and interlimb transfer of new gait patterns are facilitated by distributed practice across days

“…The phenomenon of interlimb transfer is of particular interest to rehabilitation specialists, as it has therapeutic implications for individuals with unilateral motor deficits, such as stroke or hemiparetic cerebral palsy. For example, there is a growing interest in training the lessimpaired limb to improve motor performance and functional deficits in the more-impaired limb of stroke survivors [3,4]. However, our understanding of practice strategies that could potentially enhance the transfer of motor skills from one limb to the other is limited, particularly for tasks with functional relevance, such as gait.…”

“…Interlimb transfer is the process in which training of one limb confers a benefit in performance to the opposite, untrained limb [1,2]. This ability of the neuromotor system to transfer the knowledge gained from training with one limb to the other limb is a key aspect of motor recovery in individuals with significant unilateral deficits, such as stroke or hemiparetic cerebral palsy [3,4]. Thus, understanding the processes that lead to stronger interlimb transfer may have therapeutic implications, as it can assist in the development of new treatment approaches.…”