Addressing the Pathophysiology of Mental Rotation Task (MRT) Deficits in Parkinson’s Disease Using fMRI—Defining Benchmarks
Joyeta Razzaque1, Andrew Cotton1, Khoi Le1, Bryan Mullen1, Thyagarajan Subramanian1
1The University of Toledo
Objective:
Defining fMRI benchmarks to address the pathophysiology of MRT deficits in early onset Parkinson’s Disease (EOPD) patients without any evidence for mild cognitive deficit (MCI).
Background:
We recently demonstrated that Stage I Hoehn and Yahr EOPD patients without any MCI have severe MRT score deficits compared to healthy matched controls. To understand this phenomenon, we designed a prospective brain fMRI study of MRT in EOPD subjects. We adopted the published fMRI protocol (Prescott, et. al.,) that tested the MRT in math gifted adolescents. We present the results from our age matched healthy control group to the EOPD subjects that demonstrate the difference between our data in adults to that of adolescents using identical methods.
Design/Methods:
Ten right-handed healthy male volunteers, mean age 51.1 (range 43-57) were given a 2-part MRT test. In MRT A, the rotational trial consisted of 1 target stimuli with 4 choices and baseline conditions created by Fourier transformed images presented in a pseudorandomized pattern, keeping in line with the testing pattern followed by Prescott et al.
Results:
We analyzed response accuracy and reaction times for MRT A between our group of healthy adults and the adolescent males from the reference study (mathematically gifted and control groups, n=16; mean age 14.2, range 12-16). Average percent correct was 26.1% for older adults vs 41.5% in younger, revealing a significant difference (P<0.05) which was also true for reaction times supporting our hypothesis.
Conclusions:
Our data shows the feasibility of utilizing the methods published by Prescott, et. al., to study adults with rigor and reproducibility. Testing of EOPD subjects using this protocol is ongoing to elucidate the pathophysiology of MRT deficits that could serve as an early cognitive change biomarker. Our data offers valuable insights into age-related differences in MRT performance and fMRI brain networks, enhancing our understanding of brain function as people age.