A 78-year-old male, already affected by Parkinson’s disease (PD) for the last 9 years, is the focus of this report. At diagnosis, after a good response to acute dopaminergic challenge, he was started on therapy with levodopa/Carbidopa 100 mg three times/day. At the age of 77, the patient developed daily recurrent respiratory disturbances and confused state, lasting from 2 to 4 h, which required assistance. In one of these episodes, the most severe, he was admitted to our clinic. On admission, he was confused and irritable with visual hallucinations, and dysphonic with irregular breathing as well as signs due to parkinsonism. Four hours later, the patient returned to a normal state: well-oriented, quiet and cooperative, without abnormal movements and with regular breathing. Laboratory tests, performed to exclude systemic causes, showed only a mild kidney insufficiency. Blood tests, including complete blood count, serum electrolytes, glucose, vitamin B12, vitamin E, antinuclear antibodies, lactate dehydrogenase, serum immunofixation, extractable nuclear antibody, paraneoplastic panel and angiotensinconverting enzyme concentrations, were negative or within normal limits. Thyroid, coagulation, and D-dimer and ECG were normal. Chest X-rays and CT were unremarkable. An MRI exam showed a diffused leukoencephalopathy and mild atrophy. At this point, a polygraphic exam during a levodopa challenge test was performed. Fifty minutes after the administration of 300 mg levodopa/Carbidopa, the patient presented irregular breathing and confusion. Ten minutes thereafter, the patient became agitated and uncooperative (see video). This condition lasted 4 h, and then progressively agitation and confusion decreased and breathing became regular. The polygraphy recording did not show EEG, O2-saturation and heart rate modifications, but an irregular respiratory rhythm (Fig. 1). Levodopa therapy was reduced and the episodes disappeared, although increases in bradykinesia and rigidity were observed. In PD, an underlying pulmonary dysfunction of both restrictive, partially responsive to levodopa, and obstructive type, in which levodopa induces significant variations in peak expiratory flow and upper-airway obstruction ratios, has been reported [1]. On the other hand, an acute onset of breath disorders has been described in PD in both onand off-condition [2]. To our knowledge, in on-condition, five cases of levodopa-induced respiratory disorders have been reported [3–6] (Table 1). In all patients, the decrease of dopaminergic therapy resulted in a reduction of the episodes, except for the one in which the treatment with tiapride was effective. Electronic supplementary material The online version of this article (doi:10.1007/s00415-011-6119-5) contains supplementary material, which is available to authorized users.