INTRODUCTION

Hearing loss in older adults is called presbycusis; it occurs due to degenerative changes typical of aging and manifests as sensorineural, symmetrical and bilateral hearing loss. It generally begins at age 60 and affects communication skills, which can lead to isolation and depression. ^1,2 Hearing loss is considered one of the most relevant public health problems due to its impact on older people's physical, emotional and social well-being. ^3,4

Some cases combine presbycusis with cognitive impairment that produces a series of neuropsychological changes, which are usually slow and progressive ⁵ and influence the communication process. ⁶

Presbycusis is the origin of oral communication problems, which, by limiting perceptual-cognitive stimulation in older people with deafness, also becomes a risk factor for cognitive problems. ^7,8

An individual's cognitive function results from the global functioning of perception, attention, visuospatial ability, orientation, memory, language and calculation, some of which suffer a variable degree of deterioration with aging. ^9,10

Older people affected by hearing loss experience difficulties in normally understanding the speech of their interlocutor, especially in noisy environments, in excessively fast speech delivery or with different interlocutors simultaneously. ^11-13

Cognitive impairment also alters the perception and processing of acoustic information transmitted through speech involving thinking, memory, language, judgment, and the ability to learn new things. ^14-15

There are studies in our country about the relationship between older adults and cognitive deterioration, which concluded that cognitive deterioration frequently occurs in hospitalized older adults and is associated with a large number of syndromes and geriatric problems, which gives this condition a complex nature and difficult to manage. ¹⁶

Livia et al. ¹⁷ evaluated 210 older adults between 60 and 100 years old, with the aim of identifying the prevalence of cognitive impairment in people of this age group; The Pfeiffer mental state questionnaire and the Folstein Minimental were applied, the prevalence of cognitive impairment with Folstein was 8.6% and with the Pfeiffer questionnaire 6.1%, the concurrent validity between Folstein and Pfeiffer was 0.55 (p=000 ); both instruments measure the same.

At the international level, Valero et al. ¹⁸, in their research, reported that when relating the results of tone audiometry and the Mini-Mental State Examination (MMSE), they found a statistically significant relationship between hearing loss and the detected cognitive impairment (r=0.510 r²= 0.238 (p>0.001)) In other words, the scores observed in the samples of people evaluated about cognitive impairment are essentially influenced by hearing loss.

In research conducted in the United States, hearing loss and cognitive decline were studied in 1984 older adults, which concluded that people with hearing loss have a 24% greater risk of cognitive decline. ¹⁹

In another research carried out in Barcelona, the relationship between hearing and cognition was analyzed in 162 older adults, for which an audiometric evaluation and the Pfeiffer questionnaire were applied. It was concluded that the tendency to suspect cognitive impairment increases as hearing loss increases. ²⁰

The main objective of this research was to determine the relationship between hearing loss and cognitive impairment in older adults. Furthermore, the research is essential because it allows us to determine if hearing loss in older adults influences, in some way, cognitive deterioration in a public hospital center in Lima.

METHODS

RESULTS

The results obtained aimed to determine if there is a correlation between hearing loss and mild cognitive impairment in elderly patients. Likewise, correlate these two variables using the Spearman correlation coefficient. A total of 104 patients were studied, ranging in age from 65 to 90 years. When audiometry was performed, 58 cases were found to have bilateral hearing loss, and 46 cases presented normoacusis (Figure 1).

Figure 1.  Grade of hearing in 104 patients from study. 

When performing the average hearing threshold at frequencies 500, 1000, 2000, and 4000Hz in the cases that presented hearing loss, greater loss is evident in the high frequencies (2KHz and 4KHz) that correspond to high-pitched tones or sounds (Table 1).

According to the liminal tone audiometry results and the Pfeiffer questionnaire, the sample was organized into four subgroups according to hearing and cognitive status (Table 2).

When grouping the sample, the hearing status was reflected by 58 cases (55.8%) who presented hearing loss (hypoacusis), and 46 cases (44.2%) did not show hearing loss (normoacusis). When applying the Pfeiffer questionnaire to determine cognitive status, a global or average score of 8.5 was obtained; Thus, it was determined that values less than 8 show the presence of cognitive impairment. Of the 46 cases that did not have hearing loss, 8 presented mild cognitive impairment, which represents 7.7%. Of the 58 cases that had hearing loss, 27 presented mild cognitive impairment, which represents 26% (Figure 2).

Figure 2.  Grouping of the sample according to hearing status and cognitive status. 

To determine the correlation that exists between hearing loss and cognitive impairment, we use the Spearman correlation. A high positive correlation was found between both variables: 0.864, with a statistically significant relationship (p < 0.01): Table 3.

DISCUSSION

When analyzing the results obtained in the present investigation, the average hearing threshold of the 58 cases (55.8%) with hearing loss was symmetrical and bilateral, which demonstrates that it is characteristic of the hearing loss of aging, as mentioned by Valero et al. ¹⁸, Aragón et al. ²² and Pedraza Z and Delgado M. ²³

When analyzing the results of the liminal tone audiometry and the Pfeiffer questionnaire, it was found that 44% of cases did not present hearing loss, of which 7.7% had mild cognitive impairment. This indicates that there is a prevalence of cognitive impairment in older adults, which agrees with the research of Livia et al. ¹⁷ by pointing out that in their study, there is a prevalence of cognitive impairment of 8.6% in the Pfeiffer test, while 58 cases (55.8%) presented hearing loss, of which 26% presented mild cognitive impairment. There is evidence of a close relationship between hearing loss and cognitive deterioration in older adults, which agrees with the research by Valero et al. ¹⁸ and Lin et al. ¹⁹

In the present investigation, it is evident that of the 46 cases that did not present hearing loss, 7.7% showed cognitive deterioration, while the 58 cases with hearing loss had 26% cognitive deterioration. Hearing loss influences in some way the cognitive decline in the elderly, which has an impact on their personal, family and social environment; This is similar to the research by Estrada et al. ²⁴ and Valero et al. ¹⁸

To determine a relationship between hearing loss and cognitive impairment, inferential analysis has been used using Spearman's correlation coefficient. A value of 0.864 was found, which shows a high positive correlation between both variables; This agrees with the research of Valero et al. ¹⁸, Pedraza and Delgado ²³.

CONCLUSIONS

There is a high positive relationship between hearing loss and cognitive impairment in older adults who attended the Audiology unit of the Otorhinolaryngology service of the Hospital Nacional Arzobispo Loayza, Lima.