Patients with Parkinson’s disease (PD) have not only motor impairment but also sexual dysfunction as a one of non-motor impairment. Sexual dysfunction is a common non motor impairment in patients with PD, and which not only impairs quality of life but also disturbs mood and marital relationship and results in mental dysfunction and divorce. There is growing evidence that some symptoms can precede the classical motor features of Parkinson’s disease. Premotor symptoms in Parkinson’s Disease include constipation, loss of smell, sleep disturbances such as REM sleep behavior disorder (RBD), and mood disturbances like depression. As autonomic dysfunction, lower urinary tract dysfunction (LUTD) in Parkinson’s disease is also a well-known non-motor feature.  A recent report of one case with long standing lower urinary tract dysfunction (LUTD) and orthostatic hypotension diagnosed as pure autonomic failure (PAF) but evolving into Parkinson’s disease later on, suggest that lower urinary tract dysfunction (LUTD) may occasionally precede motor symptoms of Parkinson’s disease.  Sexual dysfunction in Parkinson’s disease is also a well-known non-motor feature. However, there are few studies to investigate whether sexual dysfunction is one of premotor symptoms and how long sexual dysfunction precedes motor symptoms. Thus we investigate whether sexual dysfunction precedes the classical motor symptoms of Parkinson’s disease.

Forty-eight de-novo Parkinson’s disease patients who were mean age of 67 were recruited (male: 31, female: 11). We questioned the existence and duration of their sexual symptoms and classical motor symptoms (parkinsonism). The questionnaire for sexual dysfunction concerned difficulty to develop or maintain an erection of the penis, evacuation dysfunction, decrease in libido and  unknown.

Forty-two patients (88%) out of 48 complained of sexual symptoms. Their Initial symptoms were the difficulty to develop or maintain an erection of the penis (2.3%), the difficulty to develop or maintain an erection of the penis + evacuation dysfunction (23%) , decrease in libido (57%), and unknown (17%). These incidence rates were significantly higher than the previous studied rates in healthy subjects. In 11 patients out of 48 (23%), onset of sexual symptoms preceded classical motor symptoms by an average time of 60 months (12 - 156 months).

Sexual dysfunction preceded the classical motor symptoms of Parkinson’s disease.  decrease in libido, one of the sexual dysfunction, was the most frequent preceding symptom.  In addition, difficulty to develop or maintain an erection of the penis was possible to be preceding symptom in male.

Sexual dysfunction may precede the motor symptoms of Parkinson’s disease, and which, in particular decrease in libido, may be one of symptom of prodromal phase in Parkinson’s disease.