Hearing impairment in Parkinson's disease: expanding the nonmotor phenotype

The impact of deep brain stimulation on tinnitus

Background:

Tinnitus is a disorder of the nervous system that cannot be adequately treated with current therapies. The effect of neuromodulation induced by deep brain stimulation (DBS) on tinnitus has not been studied well. This study investigated the effect of DBS on tinnitus by use of a multicenter questionnaire study.

Methods:

Tinnitus was retrospectively assessed prior to DBS and at the current situation (with DBS). From the 685 questionnaires, 443 were returned. A control group was one-to-one matched to DBS patients who had tinnitus before DBS (n = 61). Tinnitus was assessed by the tinnitus handicap inventory (THI) and visual analog scales (VAS) of loudness and burden.

Results:

The THI decreased significantly during DBS compared to the situation prior to surgery (from 18.9 to 15.1, P < .001), which was only significant for DBS in the subthalamic nucleus (STN). The THI in the control group (36.9 to 35.5, P = 0.50) and other DBS targets did not change. The VAS loudness increased in the control group (5.4 to 6.0 P < .01).

Conclusion:

DBS might have a modulatory effect on tinnitus. Our study suggests that DBS of the STN may have a beneficial effect on tinnitus, but most likely other nuclei linked to the tinnitus circuitry might be even more effective.

Hearing and dementia

Hearing deficits associated with cognitive impairment have attracted much recent interest, motivated by emerging evidence that impaired hearing is a risk factor for cognitive decline. However, dementia and hearing impairment present immense challenges in their own right, and their intersection in the auditory brain remains poorly understood and difficult to assess. Here, we outline a clinically oriented, symptom-based approach to the assessment of hearing in dementias, informed by recent progress in the clinical auditory neuroscience of these diseases. We consider the significance and interpretation of hearing loss and symptoms that point to a disorder of auditory cognition in patients with dementia. We identify key auditory characteristics of some important dementias and conclude with a bedside approach to assessing and managing auditory dysfunction in dementia.

Association of Parkinson's disease with hospitalization for traumatic brain injury

PURPOSE

The goal of our study was to determine if patients with Parkinson's disease (PD) are more susceptible to hospitalization for traumatic brain injury (TBI).

METHODS

The US Nationwide Inpatient Sample database was queried (2004-2011) to identify cohorts of patients with PD (N = 1 047 656) and without PD (N = 115 95 173). The age range of the study population was 60-89 years. The incidence of TBI among patients with PD was compared to the incidence of TBI in patients without PD. A multivariate logistic regression model, adjusted for all covariates that significantly differed in the bivariate analyses, was used to determine if PD was an independent predictor of TBI hospitalization.

RESULTS

The incidence of TBI hospitalization was significantly higher (relative risk: 1.76, 95% CI: 1.73-1.80) in the PD cohort. The PD cohort with TBI had fewer comorbidities and risk factors for falls/TBI compared to the non-PD cohort with TBI. The multivariable analysis, adjusting for other TBI risk factors, revealed that PD status increased the likelihood of TBI hospitalization (odds ratio: 2.99, 95% CI: 2.93-3.05).

CONCLUSION

Our study shows that patients with PD are more susceptible to hospitalization for TBI. A greater proportion of fall-related TBI occurs in patients with PD compared to patients without PD. Further research is needed to prevent falls in PD patients to avoid TBI.

The Relationship Between Speech Production and Speech Perception Deficits in Parkinson's Disease

PURPOSE

This study investigated the possible relationship between hypokinetic speech production and speech intensity perception in patients with Parkinson's disease (PD).

METHOD

Participants included 14 patients with idiopathic PD and 14 matched healthy controls (HCs) with normal hearing and cognition. First, speech production was objectified through a standardized speech intelligibility assessment, acoustic analysis, and speech intensity measurements. Second, an overall estimation task and an intensity estimation task were addressed to evaluate overall speech perception and speech intensity perception, respectively. Finally, correlation analysis was performed between the speech characteristics of the overall estimation task and the corresponding acoustic analysis. The interaction between speech production and speech intensity perception was investigated by an intensity imitation task.

RESULTS

Acoustic analysis and speech intensity measurements demonstrated significant differences in speech production between patients with PD and the HCs. A different pattern in the auditory perception of speech and speech intensity was found in the PD group.

CONCLUSIONS

Auditory perceptual deficits may influence speech production in patients with PD. The present results suggest a disturbed auditory perception related to an automatic monitoring deficit in PD.

Are individuals with Parkinson's disease capable of speech-motor learning? - A preliminary evaluation

INTRODUCTION

The benefits of different practice conditions in limb-based rehabilitation of motor disorders are well documented. Conversely, the role of practice structure in the treatment of motor-based speech disorders has only been minimally investigated. Considering this limitation, the current study aimed to investigate the effectiveness of selected practice conditions in spatial and temporal learning of novel speech utterances in individuals with Parkinson's disease (PD).

METHODS

Participants included 16 individuals with PD who were randomly and equally assigned to constant, variable, random, and blocked practice conditions. Participants in all four groups practiced a speech phrase for two consecutive days, and reproduced the speech phrase on the third day without further practice or feedback.

RESULTS

There were no significant differences (p > 0.05) between participants across the four practice conditions with respect to either spatial or temporal learning of the speech phrase. Overall, PD participants demonstrated diminished spatial and temporal learning in comparison to healthy controls. Tests of strength of association between participants' demographic/clinical characteristics and speech-motor learning outcomes did not reveal any significant correlations.

CONCLUSIONS

The findings from the current study suggest that repeated practice facilitates speech-motor learning in individuals with PD irrespective of the type of practice. Clinicians need to be cautious in applying practice conditions to treat speech deficits associated with PD based on the findings of non-speech-motor learning tasks.

Aging of perennial cells and organ parts according to the programmed aging paradigm

If aging is a physiological phenomenon-as maintained by the programmed aging paradigm-it must be caused by specific genetically determined and regulated mechanisms, which must be confirmed by evidence. Within the programmed aging paradigm, a complete proposal starts from the observation that cells, tissues, and organs show continuous turnover: As telomere shortening determines both limits to cell replication and a progressive impairment of cellular functions, a progressive decline in age-related fitness decline (i.e., aging) is a clear consequence. Against this hypothesis, a critic might argue that there are cells (most types of neurons) and organ parts (crystalline core and tooth enamel) that have no turnover and are subject to wear or manifest alterations similar to those of cells with turnover. In this review, it is shown how cell types without turnover appear to be strictly dependent on cells subjected to turnover. The loss or weakening of the functions fulfilled by these cells with turnover, due to telomere shortening and turnover slowing, compromises the vitality of the served cells without turnover. This determines well-known clinical manifestations, which in their early forms are described as distinct diseases (e.g., Alzheimer's disease, Parkinson's disease, age-related macular degeneration, etc.). Moreover, for the two organ parts (crystalline core and tooth enamel) without viable cells or any cell turnover, it is discussed how this is entirely compatible with the programmed aging paradigm.

Speech discrimination is impaired in parkinsonian patients: Expanding the audiologic findings of Parkinson's disease

BACKGROUND AND OBJECTIVES

Hearing impairment (HI) has been previously demonstrated in patients with Parkinson's disease (PD). Pure Tone Audiometry (PTA) gives no information about patients' ability to hear and understand speech. To find out hearing ability and speech discrimination of PD patients, we expanded audiological evaluation by means of speech audiometry (SA).

PATIENTS AND METHODS

We screened a series of consecutive PD patients. Severity of motor symptoms and staging were measured by the UPDRS-III and the H&Y scales. Audiometric evaluation consisted of a standardized audiological examination, PTA and SA. Healthy age- and sex-matched subjects were selected as controls.

RESULTS

45 PD patients and 45 healthy controls were enrolled. PTA confirmed our previous finding of high-frequency HI in PD patients. The mean values for the Speech Recognition Threshold were higher in PD patients as compared with controls. PD patients were more likely to have impaired speech discrimination profiles and higher disease stages. Neither the patients nor the controls showed a significant speech-tone dissociation and rollover phenomenon.

CONCLUSION

Our results confirmed sensorineural HI in PD patients. Moreover, SA showed impaired speech discrimination abilities in PD patients as compared with control group thus expanding the audiologic findings of PD.

Assessment of brainstem function with auricular branch of vagus nerve stimulation in Parkinson's disease

Background

The efferent dorsal motor nucleus of the vagal nuclei complex may degenerate early in the course of Parkinson’s disease (PD), while efferent nucleus ambiguous, the principal source of parasympathetic vagal neurons innervating the heart, and afferent somatosensory nuclei remain intact.

Objective

To obtain neurophysiological evidence related to this pattern, we tested processing of afferent sensory information transmitted via the auricular branch of the vagus nerve (ABVN) which is known to be connected to autonomic regulation of cardiac rhythm.

Methods

In this cross-sectional observational study, we recorded (i) somatosensory evoked potentials (ABVN-SEP) and (ii) cutaneo-cardioautonomic response elicited by stimulation of the ABVN (modulation of heart-rate variability (HRV index; low frequency power, ln(LF), high frequency power, ln(HF); ln(LF/HF) ratio)) in 50 PD patients and 50 age and sex matched healthy controls. Additionally, auditory evoked potentials and trigeminal nerve SEP were assessed.

Results

Neither ABVN-SEP nor any of the other functional brainstem parameters differed between patients and controls. Although HRV index was decreased in PD patients, modulation of ln(LF/HF) by ABVN-stimulation, likely indicating cardiac parasympathetic activation, did not differ between both groups.

Conclusions

Findings do not point to prominent dysfunction of processing afferent information from ABVN and its connected parasympathetic cardiac pathway in PD. They are consistent with the known pattern of degeneration of the vagal nuclei complex of the brainstem.

Hearing and music in dementia

Music is a complex acoustic signal that relies on a number of different brain and cognitive processes to create the sensation of hearing. Changes in hearing function are generally not a major focus of concern for persons with a majority of neurodegenerative diseases associated with dementia, such as Alzheimer disease (AD). However, changes in the processing of sounds may be an early, and possibly preclinical, feature of AD and other neurodegenerative diseases. The aim of this chapter is to review the current state of knowledge concerning hearing and music perception in persons who have a dementia as a result of a neurodegenerative disease. The review focuses on both peripheral and central auditory processing in common neurodegenerative diseases, with a particular focus on the processing of music and other non-verbal sounds. The chapter also reviews music interventions used for persons with neurodegenerative diseases.

Peripheral nervous system involvement in Parkinson's disease: evidence and controversies

BACKGROUND

In recent years, non-motor features of Parkinson's disease (PD) have received increasing attention and PD is currently considered a systemic rather than a pure basal ganglia disorder. Among the systemic features, peripheral neuropathy (PN) is a recent acquisition since the first case-control study reporting increased frequency of PN in PD dates back to 2008.

METHODS

We reviewed available literature on peripheral nervous system (PNS) involvement in PD.

RESULTS

Evidence of α-synuclein deposition in the PNS and small nerve fiber deterioration in both drug-naïve and treated PD patients is becoming stronger. In addition, several recent reports documented a significant role of levodopa exposure together with group B vitamin deficiency in facilitating the development of PN and case reports suggested that treatment with continuous levodopa intestinal infusion may increase the risk of acute PN compared to both oral levodopa and other dopaminergic treatments.

CONCLUSION

It is currently debated whether PN is an intrinsic disease-related feature, a consequence of levodopa treatment or both. In this review, we will discuss the different hypotheses, as well as our perspective on open issues and controversies.

Loudness perception and speech intensity control in Parkinson's disease

The aim of this study was to examine loudness perception in individuals with hypophonia and Parkinson's disease. The participants included 17 individuals with hypophonia related to Parkinson's disease (PD) and 25 age-equivalent controls. The three loudness perception tasks included a magnitude estimation procedure involving a sentence spoken at 60, 65, 70, 75 and 80 dB SPL, an imitation task involving a sentence spoken at 60, 65, 70, 75 and 80 dB SPL, and a magnitude production procedure involving the production of a sentence at five different loudness levels (habitual, two and four times louder and two and four times quieter). The participants with PD produced a significantly different pattern and used a more restricted range than the controls in their perception of speech loudness, imitation of speech intensity, and self-generated estimates of speech loudness. The results support a speech loudness perception deficit in PD involving an abnormal perception of externally generated and self-generated speech intensity.

LEARNING OUTCOMES

Readers will recognize that individuals with hypophonia related to Parkinson's disease may demonstrate a speech loudness perception deficit involving the abnormal perception of externally generated and self-generated speech intensity.

Hearing loss may be a non-motor feature of Parkinson's disease in older people in Taiwan

BACKGROUND AND PURPOSE

The aim of this study was to explore whether hearing loss is associated with the risk of Parkinson's disease in the elderly in Taiwan.

METHODS

Using claims data of the Taiwan National Health Insurance Program, 4976 patients (aged 65 years or older) with newly diagnosed hearing loss from 2000 to 2010 were identified and 19 904 subjects without hearing loss were randomly selected as comparisons, frequency matched by sex, age and index year of diagnosing hearing loss. The incidence of Parkinson's disease by the end of 2010 and the associated risk factors were investigated.

RESULTS

The incidence of Parkinson's disease in the hearing loss group was 1.77-fold higher than that in the non-hearing-loss group (3.11 vs. 1.76 per 1000 person-years). After controlling for confounding factors, the adjusted hazard ratio (HR) of Parkinson's disease was 1.53 (95% CI 1.17, 1.99) for the hearing loss group compared with the non-hearing-loss group. Male sex (HR = 1.33, 95% CI 1.02, 1.74), age (for each year, HR = 1.06, 95% CI 1.04, 1.09), hypertension (HR = 1.70, 95% CI 1.26, 2.30) and cerebrovascular disease (HR = 1.78, 95% CI 1.37, 2.32) were also significantly associated with the risk of Parkinson's disease.

CONCLUSIONS

Hearing loss correlates with an increased risk of Parkinson's disease in the elderly. Further studies are needed to confirm whether hearing loss could be a non-motor feature of Parkinson's disease.