2011 The trajectory of apathy immediately after deep brain stimulation: from pre-surgical procedures to 6 months post-medical procedures in Parkinson's illness. 2011 Apathy and melancholy: different aspects in Parkinson's ailment. 2013 A latent course analysis of psychological disturbance in Parkinson's disease. 2015 Latent expansion-curve evaluation reveals that worsening Parkinson’s illness quality of life is driven by depression.