Background The course of change in verbal learning and recall performance in mild to moderate symptomatic Huntington’s disease (HD) patients is not entirely clear from the literature with most longitudinal studies generally showing no change.

Aims The present study investigated mild to moderate HD patient’s verbal learning, recall and recognition over a five year period.

Methods Twenty patients with mild to moderate HD were followed up annually using the Hopkins Verbal Learning Test (HVLT). At baseline the mean age of the patients was 47.2 years (SD=10.321), their total mean UHDRS motor score was 25.85 (SD=14.98).

Results It was found that patient’s total number of words immediately recalled on the HVLT learning trials significantly deteriorated over the five year study period, with patients recalling significantly less words at years 4 and 5 than when tested at baseline. More detailed analysis of serial position effects showed that although patients still demonstrated the expected U-shaped curve with preserved primacy and recency effects, poorer immediate recall was due to poorer recall for items in the middle serial positions. Delayed recall also deteriorated significantly at years 4 and 5, and the normal U-shaped serial position curve was no longer preserved. Recognition performance, however, was maintained over the 5 year period.

Conclusions This pattern of results show how immediate and delayed recall (but not recognition) of verbal learning deteriorates slowly in mild to moderate HD patients, and that this can be measured by the HVLT over a period of at least 4 years.