Citations

SummaryThe MRI technique diffusion tensor imaging (DTI) is reviewed along with microstructural changes associated with prodromal Alzheimer's disease (AD) as a potential biomarker for clinical applications. The prodromal stage of AD is characterized by mild cognitive impairment (MCI), representing a transitional state between normal aging and AD. Microstructural abnormalities on DTI are promising in vivo biomarkers of gray and white matter changes associated with the progression of AD pathology. Elevated mean diffusivity and decreased fractional anisotropy are consistently found in prodromal AD, and even in cognitively normal elderly who progress to MCI. However, quality of parameter maps may be affected by artifacts of motion, susceptibility, and eddy current‐induced distortions. The DTI maps are typically analyzed by region‐of‐interest or voxel‐based analytic techniques such as tract‐based spatial statistics. DTI‐based index of diffusivity is complementary to macrostructural gray matter changes in the hippocampus in detecting prodromal AD. Breakdown of structural connectivity measured with DTI may impact cognitive performance during early AD. Furthermore, assessment of hippocampal connections may help in understanding the cerebral organization and remodeling associated with treatment response.

Background and Purpose This case report describes the effects of long-term (10-year) participation in a community exercise program for a client with mixed features of corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). The effects of exercise participation on both functional status and brain volume are described. Case Description A 60-year-old male dentist initially reported changes in gait and limb coordination. He received a diagnosis of atypical CBD at age 66 years; PSP was added at age 72 years. At age 70 years, the client began a therapist-led community group exercise program for people with Parkinson disease (PD). The program included trunk and lower extremity stretching and strengthening, upright balance and strengthening, and both forward and backward treadmill walking. The client participated twice weekly for 1 hour for 10 years and was reassessed in years 9 to 10. Outcomes Falls (self-reported weekly over the 10-year period of the study by the client and his wife) decreased from 1.9 falls per month in year 1 to 0.3 falls per month in year 10. Balance, walking endurance, and general mobility declined slightly. Gait speed (both comfortable and fast) declined; the client was unable to vary gait speed. Quantitative brain measurements indicated a slow rate of whole brain volume loss and ventricular expansion compared with clients with autopsy-proven CBD or PSP. Discussion This client has participated consistently in a regular group exercise program for 10 years. He has reduced fall frequency, maintained balance and endurance, and retained community ambulation using a walker. Combined with the slow rate of brain volume loss, this evidence supports the efficacy of a regular exercise program to prolong longevity and maintain function in people with CBD or PSP.