A 45-year-old female patient (smoked 15 cigarettes/d) was diagnosed with HD in 2013. Neurological examination showed subtle chorea and dystonic posturing of the arms but no other motor features. Baseline cognitive testing demonstrated significant deficits in motor tapping (number of taps, nondominant), maze navigation (number of trials completed, overrun errors), and emotional identification (accuracy of fear and disgust recognition) compared to age, sex, and years of education-matched controls. No deficits were observed in any of the other cognitive domains tested.
At the time of the study, she was on no medication but had taken venlafaxine to manage depression in the past. She indicated a desire to stop smoking and had previous failed attempts. The patient successfully stopped smoking during week 2. The patient reported a single aggressive outburst that was out of character during week 2 but experienced no other side effects. After 4 weeks of varenicline treatment, UHDRS total motor score decreased from 16 to 9 with notable improvement in oculomotor function and hyperkinesia scores (Table 1). Her UHDRS behavioral subscale score was increased from 2 to 8 and could be attributed to the episode of increased irritability/aggression (Table 2). The patient self-reported an improvement in her thinking, being able to think more clearly and having a better memory. Cognitive testing showed significant improvements in maze navigation (domain-specific z-score: -3.25 vs -0.15) and facial emotion recognition (domain-specific z-score: -3.10 vs -1.50) following varenicline treatment (Figure 1). Motor-tapping deficits were not affected by varenicline treatment. She continues to be a nonsmoker and has had no further irritable outbursts.