Impaired Recognition of Facial Emotion in Patients With Parkinson Disease Under Dopamine Therapy

Differential Effects of Disease Duration and Dopaminergic Replacement Therapy on Vocal Emotion Recognition in Asymmetric Parkinson's Disease

INTRODUCTION

Recently, studies have suggested a role of motor symptom asymmetry on impaired emotional recognition abilities in Parkinson's disease with a greater vulnerability in patients with a predominance of left-sided symptoms. However, none of them explored the interaction between motor symptom asymmetry and dopamine replacement therapy in different stages of the disease.

METHODOLOGY

We explored the recognition of vocal emotion (i.e., emotional prosody) in 15 newly diagnosed Parkinson's disease patients in the early stages of the disease, 15 patients in the advanced stages of the disease and 15 healthy controls. The early patients were studied in two conditions: ON and OFF dopaminergic replacement therapy and both Parkinson's disease groups (early and advanced) were divided into two subgroups according to the asymmetry of motor symptoms.

RESULTS

The analyses revealed two patterns of results. First, as predicted, we observed a reduction in performance for the recognition of vocal emotions in patients with a predominance of left-sided symptoms as compared to both healthy controls and predominantly right-sided symptom patients. Second, in the early stages of the disease, we observed a deleterious effect of dopatherapy on the recognition of vocal emotions for the patients with left-predominant symptoms, and the inverse pattern (i.e., a positive effect of dopatherapy) for the patients with right-predominant symptoms.

CONCLUSIONS

Our results bring to knowledge the differential effects of disease duration, dopaminergic replacement therapy and motor symptom asymmetry on vocal emotion recognition in Parkinson's disease.

Deficits in emotion perception and cognition in patients with parkinson's disease: A systematic review

Non-motor symptoms (NMS) are common among Parkinson's disease (PD) patients and have a significant impact on quality of life. NMS such as deficits in emotion perception are gaining due focus in the recent times. As emotion perception and cognitive functions share certain common neural substrates, it becomes pertinent to evaluate existing emotion perception deficits in view of underlying cognitive deficits. The current systematic review aimed at examining studies on emotion perception PD in the last decade. We carried out a systematic review of 44 studies from the PubMed database. We reviewed studies examining emotion perception and associated cognitive deficits, especially executive function and visuospatial function in PD. This review also examines how early and advanced PD differ in emotion perception deficits and how the presence of common neuropsychiatric conditions such as anxiety, apathy, and depression as well as neurosurgical procedure such as deep brain stimulation affect emotion perception. The need for future research employing a comprehensive evaluation of neurocognitive functions and emotion perception is underscored as it has a significant bearing on planning holistic intervention strategies.

Disorders of facial emotional expression and comprehension

One of the most important means of communicating emotions is by facial expressions. About 30-40 years ago, several studies examined patients with right and left hemisphere strokes for deficits in expressing and comprehending emotional facial expressions. The participants with right- or left-hemispheric strokes attempted to determine if two different actors were displaying the same or different emotions, to name the different emotions being displayed, and to select the face displaying an emotion named by the examiner. Investigators found that the right hemisphere-damaged group was impaired on all these emotional facial tests and that this deficit was not solely related to visuoperceptual processing defects. Further studies revealed that the patients who were impaired at recognizing emotional facial expressions and who had lost these visual representations of emotional faces often had damage to their right parietal lobe and their right somatosensory cortex. Injury to the cerebellum has been reported to impair emotional facial recognition, as have dementing diseases such as Alzheimer's disease and frontotemporal dementia, movement disorders such as Parkinson's disease and Huntington's disease, traumatic brain injuries, and temporal lobe epilepsy. Patients with right hemisphere injury are also more impaired than left-hemisphere-damaged patients when attempting to voluntarily produce facial emotional expressions and in their spontaneous expression of emotions in response to stimuli. This impairment does not appear to be induced by emotional conceptual deficits or an inability to experience emotions. Many of the disorders that cause impairments of comprehension of affective facial expressions also impair facial emotional expression. Treating the underlying disease may help patients with impairments of facial emotion recognition and expression, but unfortunately, there have not been many studies of rehabilitation.