Degeneration of the corticofugal tract from the secondary motor area in a Parkinson's disease patient with limb-kinetic apraxia

Abstract

Rationale:In this case report, we describe a Parkinson's disease (PD) patient with limb-kinetic apraxia (LKA) in whom degeneration of the corticofugal tract (CFT) from the supplementary motor area (SMA) was observed in diffusion tensor tractography (DTT).Patient concerns:A 63-year-old woman presented with a loss of dexterity in both upper extremities, which indicated LKA, and typical PD-related symptoms, including a gait disturbance with a short step, resting tremor in both upper extremities, and rigidity, and these symptoms had been present for 2 years. The 18F-florinated-N-3-fluoropropyl-2-β-carboxymethoxy-3-β-(4-lodophenyl) nortropane positron emission tomography scanning findings were consistent with PD. Based on the clinical symptoms and imaging findings, we diagnosed the patient with PD. In a coin-rotation test that was used to evaluate the severity of the LKA, the patient's results significantly decreased compared to the results of the normal controls.Diagnoses:The DTT showed that the CFTs from the SMAs in both hemispheres were partially torn and thinned. The fractional anisotropy values and CFT volumes in both SMAs were >2 standard deviations lower than those of the normal controls.Interventions:The patient was treated with an initial dose of 150/37.5 mg/day of levodopa/benserazide, and the dose was gradually increased to 400/100 mg/day.Outcomes:After treatment, although the bradykinesia, rigidity, and resting tremor of the patient significantly decreased, the dexterity of the patient's hands did not improve.Lessons:These observations indicated degeneration of the CFTs from the SMAs in both hemispheres in the patient. This degeneration might have, at least in part, contributed to the patient's LKA. The results of this study suggest that CFT degeneration could be one of the pathological mechanisms underlying LKA in patients with PD.

Injury of the Corticofugal Tract from the Secondary Motor Area in Middle Cerebral Territory Infarction: A DTI Study

“…21,22 It also allows for three-dimensional reconstruction of the CFTs from the secondary motor area. 10,11,18,23 Some previous studies demonstrated the injury of CFTs from the secondary motor area in patients with traumatic brain injury, corona radiata infarct, and Parkinson's disease. 18,23,24 However, there is currently a lack of evidence regarding limb kinetic apraxia caused by injury of the CFTs from the secondary motor area in patients with MCA territory infarction.…”

“…[5][6][7][8][9] In the human brain, motor function is associated with various neural tracts, including the corticofugal tract (CFT), corticospinal tract (CST), corticoreticulospinal tract, and corticorubrospinal tract. [10][11][12][13][14][15] The primary function of CFTs from the secondary motor area, which is classified as the premotor cortex (PMC) and supplementary motor area (SMA), is motor planning. 16 Consequently, injury of the CFTs from the secondary motor area commonly induces limb kinetic apraxia, which is the inability to make precise or exact movements with the hands and upper or lower extremities.…”

Role of Diffusion Tensor Tractography in Diagnosis of Limb-Kinetic Apraxia in Stroke Patients: A Mini-Narrative Review

“…Several neural tracts related to motor function, including the CST, CFT, and corticoreticulospinal tract, could be reconstructed using a DTT reconstruction method [ 15 , 18 , 28 – 30 ]. As a result, many DTT-based studies have reported that LKA is related to injuries of the above neural tracts in various brain pathologies [ 2 , 7 , 15 – 19 , 23 , 32 – 34 ].…”