Purpose: Research has documented cognitive deficits both before and after high-dose treatment followed by allogeneic hematopoietic cell transplantation (HCT), with partial recovery by 1 year. This study prospectively examined the trajectory and extent of long-term cognitive dysfunction, with a focus on 1 to 5 years after treatment.
Patients and methods: Allogeneic HCT recipients completed standardized neuropsychological tests including information processing speed (Trail Making A and Digit Symbol Substitution Test), verbal memory (Hopkins Verbal Learning Test-Revised), executive function (Controlled Oral Word Association Test and Trail Making B), and motor dexterity and speed (Grooved Pegboard). Survivors (n = 92) were retested after 80 days and 1 and 5 years after transplantation. Case-matched controls (n = 66) received testing at the 5-year time point. A Global Deficit Score (GDS) summarized overall impairment. Response profiles were analyzed using linear mixed effects models.
Results: Survivors recovered significant cognitive function from post-transplantation (80 days) to 5 years in all tests (P < .0001) except verbal recall (P > .06). Between 1 and 5 years, verbal fluency improved (P = .0002), as did executive function (P < .01), but motor dexterity did not (P > .15), remaining below controls (P < .0001) and more than 0.5 standard deviation below population norms. In GDS, 41.5% of survivors and 19.7% of controls had mild or greater deficits (NcNemar test = 7.04, P = .007).
Conclusion: Although neurocognitive function improved from 1 to 5 years after HCT, deficits remained for more than 40% of survivors. Risk factors, mechanisms and rehabilitation strategies need to be identified for these residual deficits.