Olfactory dysfunction and cardiovascular dysautonomia in Parkinson’s disease

Abstract

Several studies have reported that olfactory dysfunction is an early neuropathological manifestation of Parkinson's disease (PD). Reduced cardiac meta-iodobenzylguanidine ((123)I-MIBG) uptake may be one of the earliest signs of PD. We studied the relation of olfactory dysfunction to cardiovascular dysautonomia in patients with PD. The study group comprised 66 patients with PD (70.5 years) and 26 controls (70.3 years) for olfactory assessment, 21 controls (72.1 years) for cardiac (123)I-MIBG scintigraphy and heart rate variability (HRV), assessed using the coefficient of variation for RR intervals (HRV), and 23 controls (69.2 years) for orthostatic blood pressure response. Olfactory function was assessed by the odor stick identification test Japan (OSIT-J), and cardiovascular autonomic function was evaluated by (123)I-MIBG scintigraphy of the heart, the fall in orthostatic blood pressure, and HRV. Patients with PD had a significantly lower OSIT-J score than did the controls (4.1 +/- 3.0 vs. 9.9 +/- 1.7, p = 0.001). The OSIT-J score was unrelated to variables other than gender, including age, disease duration, motor score on the unified Parkinson's disease rating scale, score on the mini-mental state examination, motor phenotype, visual hallucinations, and dopaminergic medication on multiple regression and logistic regression analyses. The OSIT-J score was related to the heart/mediastinum ratio of cardiac (123)I-MIBG uptake, the fall in orthostatic blood pressure, and HRV, after adjustment for other clinical variables. Olfactory dysfunction in PD was, thus, significantly related to both cardiac sympathetic and parasympathetic dysfunction, as well as vascular sympathetic dysfunction. As non-motor symptoms of PD, olfactory dysfunction and autonomic network failure appear to be closely related in PD.

The odor stick identification test for Japanese differentiates Parkinson's disease from multiple system atrophy and progressive supra nuclear palsy

“…This conclusion is based on the significantly lower OSIT-J score in patients with PD than the control and its high sensitivity and specificity in the diagnosis. The present results are in agreement with those of previous studies, which showed an OSIT-J score of 4.1-4.8 in patients with PD [3,5,25]. To differentiate PD from the controls, we used cutoff values for OSIT-J of 7, which yielded sensitivity of 81% and specificity of 100% (Table 2).…”

“…Another recent study also suggested that olfactory dysfunction in PD is associated with both cardiac sympathetic and parasympathetic dysfunction as well as with vascular sympathetic dysfunction after adjustment for age, disease duration, motor impairment, and dopaminergic medication. As non-motor symptoms, olfactory and autonomic network dysfunctions appear to be closely related in PD [25]. Since most PD patients appear to become anosmic during later stages of the disease, it becomes clear that the correlation between the duration of PD and olfactory function is only relevant in the relatively early stages of the disease.…”

Usefulness of Cardiac MIBG Scintigraphy, Olfactory Testing and Substantia Nigra Hyperechogenicity as Additional Diagnostic Markers for Distinguishing between Parkinson’s Disease and Atypical Parkinsonian Syndromes

“…In patients with PD, olfactory impairment has been correlated with cardiac sympathetic denervation [30, 31], even in the early stages of the disease [32]. Lee et al [33] reported that the degree of cardiac sympathetic dysfunction, as evaluated by cardiac MIBG scintigraphy, was positively correlated with the degree of olfactory identification impairment in patients with PD but not in patients with MSA.…”

Application of odor identification test in Parkinson's disease in China: A matched case-control study

“…Therefore, in theory, a correlation of olfaction with autonomic function may exist in early PD. Several studies [29] indicated that olfactory dysfunction in PD was significantly related to both cardiac sympathetic and parasympathetic dysfunctions, as well as vascular sympathetic dysfunction. These dysfunctions were respectively reflected by cardiac 123I-MIBG scintigraphy, heart rate variability and orthostatic hypotension.…”