Parkinson Disease (PD) is a neurodegenerative disease for which no cure is available yet. It is the second largest neurological disease affecting an estimated 571 per 100,000 people in Europe with rising prevalence due to the aging population (Pringsheim et al., 2014). To date, dopamine-replacement therapy (DRT) is the first choice of treatment to lessen the impact of motor and non-motor symptoms, however DRT does not prevent progressive disabilities and does not change the course of the disease (Chaudhuri et al., 2006; Jankovic and Stacy, 2007). Therefore, other types of therapy are needed to supplement DRT.
Recent evidence suggests that physical activity and vigorous exercise may have the potential to slow disease progression (for an overview see Hirsch and Farley, 2009; Ahlskog, 2011; van Wegen et al., 2014). These findings are promising, however they require further investigation. The effects of physical activity and regular exercise on reducing the chance of developing secondary problems e.g., diabetes or cardiovascular disease are quite established (Lee et al., 2012). Nevertheless, inactivity is a major problem as patients with PD are approximately one third less active than age matched controls (van Nimwegen et al., 2011). Being physically active may be more difficult for patients with PD because of physical impairments, fatigue, and apathy (van Nimwegen et al., 2011). Physical rehabilitation, containing a variety of exercise interventions (e.g., individual and in groups) is recommended for patients with PD (Keus et al., 2014).
Partnered dancing
The European guideline for Parkinson's disease recommends dance as a meaningful approach to improve functional mobility and balance (Keus et al., 2014). However, this recommendation is based only on three proof-of-concept trials that investigate Tango dancing (Hackney et al., 2007; Hackney and Earhart, 2009a; Duncan and Earhart, 2012).
Several reviews have been published that included more studies regarding music based movement therapy and dance (de Dreu et al., 2012, 2014; Sharp and Hewitt, 2014; Shanahan et al., 2015a). A recent meta-analysis including five randomized clinical trials suggests significant positive effects of dance therapy on motor impairment, balance, gait speed, and health-related quality of life (Sharp and Hewitt, 2014). A systematic review investigating multiple types of dance found significant positive effects on endurance, motor impairment, and balance (Shanahan et al., 2015a). Furthermore, our meta-analysis investigating several types of music based movement therapies (dance and gait-based interventions using music as an auditory rhythmic cue) found significant positive effects on balance performance, UPDRS-II, walking velocity, stride length, dual task walking velocity, 6 m walk test, and the timed-up-and go test (de Dreu et al., 2012, 2014).
Most studies on dance in patients with PD have investigated Tango dancing (Hackney et al., 2007; Hackney and Earhart, 2009a,b,c, 2010a,b; Duncan and Earhart, 2012; Foster et al., 2013; McKee and Hackney, 2013; Duncan and Earhart, 2014). In addition, one study on Ballroom dancing (Hackney and Earhart, 2009a,b) and two pilot studies on Irish set dancing (Volpe et al., 2013; Shanahan et al., 2015b) were published. Salsa dance classes for patients with PD are available in the Netherlands and in Canada (Ottawa). Furthermore, there are organizations in several countries providing modified modern dance classes and/or ballet classes (not partnered dancing) for patients with PD, e.g., Dance for PD (New York), Dance for Parkinson's (London), Queensland ballet, and Dance for Health (multiple cities in The Netherlands). Some small pilot studies have investigated these types of dance (Westbrook and McKibben, 1989; Batson, 2010; Heiberger et al., 2011), however the effectiveness of Salsa dance classes remains to be established in methodologically well-conducted randomized controlled trials.
Partnered dancing combines exercise with cognitive challenges in an enriched environment with (somato) sensory cues from the music as well as from the dance partner (Blasing et al., 2012). The sensory cues from physical contact with the partner are specifically important during Tango and Salsa dancing. While Ballroom and Irish set dancing often have a predefined routine that is executed from start to end in the way that people are required to learn the entire routine by heart, Tango and Salsa dancing do not necessarily have such a routine, providing more flexibility in performance. During Tango and Salsa classes, participants are taught several short steps with specific somatosensory cues (signals) for each step (e.g., with a length of 8 or 16 counts in the music). Subsequently, the couple can apply these steps in any sequence. A dancing couple consists of a leader (traditionally the man) and a follower (traditionally the woman). However, this format is sometimes changed, e.g., in the studies about Tango dancing men and women practiced both the leading and following roles (Hackney and Earhart, 2010b). The leader determines which routine comes next and the follower responds to the somatosensory cues of the leader. This requires clear communication. An example in this context is a right turn for the follower, this can be indicated by the leader by raising the hand of the follower gently above his/her head, indicating the direction of the turn by choosing a spot just right or left from the center of his/her head. We advise the follower to turn with small steps in their own tempo and the leaders to follow the tempo of the followers. Some of these steps in Salsa and Tango are similar to physiotherapeutic strategies and training for weight shifting, turning, and backwards walking (Kamsma et al., 1995; Earhart, 2009). Consequently, there is a relatively high demand of planning skills for the leader and the responsiveness to somatosensory cues for the follower. In line with these observations, McKee and Hackney found that spatial cognition and executive function improved after 10 weeks of Tango dancing classes (McKee and Hackney, 2013). This finding is important in light of the decline of spatial cognition in neurodegenerative disease (Possin, 2010). These interactions resemble those with caregiver-mediated exercises after stroke (Galvin et al., 2011; Vloothuis et al., 2014) and may improve not only the functional mobility of patients but also decrease feelings of caregiver burden through mechanisms of empowerment and self-management. However, the effect of partnered dance on caregiver burden needs further investigation.