Functional brain effects of hand disuse in patients with trapeziometacarpal joint osteoarthritis: executed and imagined movements

Abstract

The human trapeziometacarpal (TMC) joint has a crucial evolutionary importance as it permits rotation and opposition of the thumb to the other fingers. In chronic TMC joint osteoarthritis (i.e., rhizarthrosis), this motor ability, essential for pinching, grasping, and manipulating objects, may become difficult or impossible due to intolerable pain. Here, we assess whether patients with rhizarthrosis show signs of abnormal brain representation of hand movements. To this end, we studied 35 patients with rhizarthrosis, affecting predominantly one of the two hands, and 35 healthy subjects who underwent both behavioural and fMRI measures of brain activity during overtly executed or imagined thumb-to-finger-opposition movements. The patients with rhizarthrosis were slower than controls both in motor execution and imagination. In the patients, correlation between the motor execution and imagination times was preserved, even though such correlation was less strong than in normal controls. The fMRI measures showed reduced activation in the hand primary motor and dorsal premotor cortex for the patients only during explicit movements. This was true for both hands, yet more so for the most affected hand. No significant differences were seen for the motor imagery task. These results show that an orthopaedic disorder that reduces patients' motoric repertoire in the absence of any neurological impairment is sufficient to induce neurofunctional changes in the cortical representation of hand movements. The substantial preservation of motor imagery with its neural counterparts distinguishes the neurological patterns of rhizarthrosis from those of complete immobilization or amputation suggesting that motor imagery may be used to boost motor recovery in rhizarthrosis after surgical treatment.

A functional limitation to the lower limbs affects the neural bases of motor imagery of gait

“…Our patients were tested near the end of a long period of impaired walking that not only made them slower during a short walk, as expected, but also undermined their ability to accurately imagine the task. This observation is in line with evidence for lower isochrony in hand movements in patients with trapeziometacarpal osteoarthritis ( Gandola et al, 2017 ). The present study shows for the first time that a musculoskeletal disorder of the lower limbs might impact on central motor representations of gait, although gait is considered a highly automatic behaviour.…”

“…Orthopaedic patients, with no history of major neurological disorder, represent a case of special interest for studying maladaptive brain plasticity following chronic disuse of a body district and defining the eventual benefit of mental training programmes in subjects with functional limitations. We recently tested patients with trapeziometacarpal osteoarthritis and found signs of maladaptive plasticity, as shown by brain activation during finger opposition tasks ( Gandola et al, 2017 ). One could argue that the hand, and the precision grip in particular, has a special status for human survival ( Napier and Napier, 1985 ; Napier, 1993 ), making it an apt tool for detecting brain abnormalities associated with chronic disuse.…”

Effectiveness of motor imagery and action observation training on musculoskeletal pain intensity: A systematic review and meta‐analysis

“…Studies have shown that both AO and MI can cause an increase in cortical representation and excitability, influencing areas such as the primary motor cortex and the dorsal premotor cortex (Buccino et al, ; Caspers et al, ). In this regard, Gandola et al () had shown that disuse of a hand after surgery was associated with neurofunctional changes and reduced cortical representation in the hand primary motor and dorsal premotor cortex. However, these authors had found that the MI task was preserved; thus, they suggested the use of motor representation techniques after surgical treatment.…”

Motor imagery training speeds up gait recovery and decreases the risk of falls in patients submitted to total knee arthroplasty

“…However, both osteoarthritis and the immobilization and pain after surgery induce a motor impairment that is also associated with changes in the activation of motor brain circuits. For instance, we previously demonstrated that rhizarthrosis is associated with cognitive and neurofunctional changes in the mental representation of hand movements 3 . Patients with rhizarthrosis were slower than healthy controls both in the motor execution and in the imagination of hands movement and they showed reduced activation in the hand primary motor and dorsal premotor cortex when executing hand movements 3 .…”