Response of parkinsonian swallowing dysfunction to dopaminergic stimulation

Abstract

Objectives-To determine the degree of dopaminergic response of swallowing dysfunction in Parkinson's disease. Methods-Fifteen patients with idiopathicParkinson's disease and symptomatic dysphagia were studied. All had motor fluctuations in response to long term levodopa therapy. On two separate days, after overnight withdrawal of all antiparkinsonian medication, a modified barium swallow using cinefluoroscopy and diVerent food consistencies was performed before and after administration of oral levodopa and subcutaneous apomorphine. Results-Despite all patients having an unequivocal motor response to both agents, there were few significant responses in any of the quantitative or qualitative criteria of swallowing dysfunction assessed. The oral preparatory phase, generally considered a more voluntary component of swallowing, showed a response, but not with all consistencies. In a subgroup of patients the pharyngeal phase time also improved. Conclusions-These findings suggest that parkinsonian swallowing dysfunction is not solely related to nigrostriatal dopamine deficiency and may be due to an additional non-dopamine related disturbance of the central pattern generator for swallowing in the pedunculopontine nucleus or related structures in the medulla. (J Neurol Neurosurg Psychiatry 1997;63:579-583) Keywords: apomorphine; levodopa; Parkinson's disease; swallowing dysfunction Swallowing dysfunction is common in idiopathic Parkinson's disease, being symptomatic in up to 50% of patients but seen in more than 90% using videofluoroscopy. [1][2][3] It is usually considered multifactorial with abnormalities documented in all phases of swallowing. [2][3][4][5][6][7][8][9] In the oral phase poor bolus formation, lingual festination and tremor, and repetitive tongue elevation are characteristic. In the pharyngeal phase the swallow reflex can be delayed; there may be slowing of pharyngeal transit and pooling in the valleculae and pyriform sinuses. Dysfunction of the upper oesophageal sphincter with incomplete relaxation and reduced opening is also common. 2-4 7 9In the oesophageal phase abnormal oesophageal peristalsis and gastro-oesophageal reflux can be seen.1-3 These factors increase the risk of laryngeal penetration and aspiration.3-6 A disruption of the normal sequencing of swallowing may underlie these abnormalities. 7It remains unclear just how responsive these disturbances are to pharmacological intervention. Swallowing dysfunction in Parkinson's disease has traditionally been grouped along with speech and postural disturbance as being resistant to levodopa although evidence for this is not strong. 4 8 10 11 We have studied the response of parkinsonian swallowing dysfunction to dopaminergic stimulation with levodopa and the directly acting dopamine receptor agonist apomorphine, using both qualitative and quantitative variables obtained from videofluoroscopic assessment. Patients and methodsFifteen patients (12 men, three women) fulfilling the United Kingdom brain bank criteria for the diagnosis of Parkinso...

Effects of Therapy for Dysphagia in Parkinson’s Disease: Systematic Review

“…Some studies did not have an adequate method of randomization for referral to different intervention groups, e.g., Iwasaki et al [23] and Bushman et al [27] did not score pre-versus posttreatment blinded for the schedule of treatment [4,24,[26][27][28], nor did they have an adequate placebo or control population [7,15,17,22,[26][27][28][29]. Very often a control group receiving no therapy for dysphagia when in fact an indication for treatment is present is regarded as unethical and therefore usually not approved by any medical ethical committee.…”

“…Now it seems as if L-dopa failed to have an effect in an already normal radiologic pattern of deglutition, whereas the information of the total swallowing act was incomplete. In some articles no information was given about the Parkinson's disease severity scale [19,21,22,31]. Some authors did not describe the ''on'' or ''off''-motor phase during the examinations and therapy [7, 19-21, 23, 29, 31].…”

“…Hunter et al [22] studied the degree of dopaminergic response of swallowing dysfunction in 15 patients with Parkinson's disease. After a minimum of 8 h of withdrawal from antiparkinsonian medication, the patients received a single oral dose of 250 mg of levodopa plus 25 mg of carbidopa on the first study day.…”

Characterization of Corticobulbar Pharyngeal Neurophysiology in Dysphagic Patients With Parkinson's Disease

“…27,28 In the present cohort, 6 of 26 patients were in the SIon group, suggesting that the effect may be more common than suspected. One possible explanation is that on-phase dysphagia is similar to a dyskinetic effect of medication on the swallowing pathway.…”

“…Finally, it is worth noting that although there was no improvement in aspiration scores, levodopa treatment did reduce the number of secondary clearing swallows, in keeping with previous observations. 27 It has been suggested that rigidity and bradykinesia of oral musculature may compromise the oral preparatory phase, which is under volitional motor control. These are the symptoms most likely to be ameliorated by treatment, and it therefore would seem logical to have some improvement of oral bolus control.…”