London: Rapid eye movement (REM) sleep behaviour disorder, which involves abnormal behaviour when one experiences nightmares and vivid dreams, could lead to Parkinson`s disease.
People find themselves screaming, crying or punching when they are being attacked and pursued, especially during nightmares, in the sleep disorder.
Àlex Iranzo, neurologist at the Hospital Clinic of Barcelona, Spain conducted three studies to establish the link between REM disorder and Parkinson`s.
His latest study applied brain SPECT (test to measure dopamine levels) to conclude that Parkinson`s patients have lower levels of this hormone, according to Lancet Neurology.
In Parkinson`s, dopamine deficiency in brain region substantia nigra -- linked with learning and harmony of movements -- causes tremors and stiffness, according to a Hospital Clinic statement.
The hormone is released by rewarding experiences such as food, sex, drugs and neutral stimuli.
Results show that after three years of monitoring production in the control group, dopamine was reduced by eight percent due to age, while the group of REM disorder patients experienced a reduction of 20 percent.
Once the three-year follow-up ended, three of 20 patients with REM sleep disorder had developed Parkinson`s and their dopamine reduction was around 30 percent.
Study authors suggest that a drug should significantly prevent the dopamine concentration from dropping in these patients.