WGHI - Working Group on Hearing Impairment
Statistics on age and disability and in relation to Telecommunications - A significant market
By
W J Mellors
Contents
Summary
The Elderly Population
European Community Figures
Greater Europe
Conclusions
Disability
Hearing Impairment
Conclusions
Other Hanicaps
References
Summary
Statistics of ageing in Europe are reviewed, the differences in sources are noted and best estimates are obtained which show that the elderly population is increasing.
A study is made of information and the statistics relating to hearing impairment and the reason for many of the published discrepancies are explained.
It is shown that there is a significant market to be addressed among those who are elderly and/or
disabled which represents some 20 to 25% of the population.
The elderly population
The Shorter Oxford English Dictionary describes elderly as "somewhat old, verging on old age, of or pertaining to an elderly person". It gives no assistance as to at what age this condition begins, and in the experience of many, an elderly person is someone at least ten years older than oneself. Others consider being elderly is when growing disabilities begin to have a significant effect on ones lifestyle.
There is no fixed age at which someone becomes old, in fact different societies use different criteria. Among some groups in Kenya a man is considered old when the smell of food no longer awakens him, and a woman when she keeps dropping the cooking pot! This view directly relates age with disability. In other societies a person is considered old on the birth of his first grandchild [1]. In Western society, ageing is defined on an arbitrary basis, mainly as a result of employment and pensions legislation, and is considered to occur at some age between 60 and 65 dependent on gender and nationality.
Thus the conventional boundary of old age is purely a chronological event and bears little relation to when a person actually feels old or gives the appearance of being elderly.
For the purposes of this UK study, an age of 65 has been used. Being old in itself is of no direct
significance in relation to telecommunications. It is the onset of various age related disabilities
that is of importance.
European Community figures
In a paper given to the second COST conference on telecommunications and disability John McEwan quoted [2] the following data for the European Community, giving figures identical to those later given in Europe in figures [3].
Percentage over 65 in EEC
| 1990 |
13.6%
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| 2000 |
14.7%
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| 2010 |
16.0%
|
| 2020 |
18.1%
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| 2030 |
20.8%
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| 2040 |
22.4%
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| 2050 |
21.6%
|
11 - 15% of the population of 322 million are said to have some form of disability. Using this same
population figure, the 13.6% over 65 in 1990 represent 43.9 million people.
More detailed figures given in the Economist Book of vital world statistics give an figure of 14.2% over 65 years of age representing 46.18 million out of a total population of 324.78 million.
These figures are in close agreement.
For 2010 The Economist Book of vital world statistics projects the a figure of 17.1% over 65 in
the year 2010 which compares reasonably well with the figure of 16.0% quoted by McEwan.
Greater Europe
Statistics for the rest of geographical Europe (plus Asian USSR) from the Economist Book of vital world statistics give a figure of 9.8% over 65years of age representing 49.57 million out of a population of 507.66 million.
These sets of figures taken together give a total population in geographical Europe + USSR Asia of 832.44 million in 1988, of which 11.50 % (95.75 million) are over 65.
This figure of 95.75 million over 65 in 1990 is fairly close to the figure of 88 million (100 million
said to be elderly) given in "The forgotten millions" [4] as the European
population aged 65 or over and suggests that the figures given in this source represents numbers in
the larger area of geographical Europe.
The Economist Book of vital world statistics gives a total population in geographical Europe + USSR
Asia of 915.90 million in 2010 of which 13.85 % (126.84 million) are over 65.
This figure of 126.84 million in 2010 can be compared with the equivalent figure of 105 millions quoted in "The forgotten millions" [4].
In the countries considered to be western Europe (the present EU plus Iceland, Norway and Switzerland), in 2010 the total population will be 378.89 million of which 65.14 million (17%) will be over 65 years of age.
There is a growing tendency to use the age of 60 years to describe the onset of old age. Sandhu [5] gives a figure of 68.7 million over 60 in the European Community (of a population of approximately 322 million this probably in 1988 - 1990)
Conclusions
Making a best estimate from these three sources it seems that in the European Community in 1990 some 14% of the population was over 65 and that this figure will rise to 16 or 17% in the year 2010. Equivalent figures for the United Kingdom are 15.5% in 1990 rising to 16.1% in 2010.
In greater Europe the percentage of the population over 65 in 1990 was probably about 11% which will rise to about 13% in 2010.
Disability
The available information on disability is considerably more confused than that on ageing, probably due to differing assessments of the significance of any reported disability. A survey on transport for handicapped persons in Europe [6] reported figures for the disabled population ranging from 1.6% in Switzerland to 25% in Spain! These figures are often quoted to show that the statistics on disability are inaccurate and often appear to be taken out of their context which was clearly related to physical disability and the use of public transport, but nevertheless do show an amazing range.
In relation to telecommunications there is a worry that new techniques such as computer supported telephony are denying facilities to people with a wider range of disabilities. The particular disability that in the past has had most effect on telecommunications has been hearing impairment and, as there is more relevant information on this than on the effect on telecommunications of other disabilities, the present study concentrates on it.
Hearing Impairment
Estimates for the percentage of the population with impaired hearing range from 0.24% [7] to 15% [8]. Why is there such a range? It is evident that the quoted figures are sometimes for those with severe disablement and at other times for those with just measurable impairment. Where should the line be drawn?
In the context of this study the effect of hearing impairment on the use of the telephone is of greatest significance. Some useful background information is given in the work of Beasley [9] and Plomp [10] in the USA.
Beasley used the classification shown in table 2 and Plomp extended the work to add values for average hearing loss (AHL=average hearing loss at 500, 1,000, and 2,000Hz on the better ear) to the classifications.
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| 1) Partial deafness Stage 1 | The individual has difficulty in understanding speech in auditoria and in group conversation, but can hear speech at close range without any artificial aid. | ³ 24 dB |
| 2) Partial deafness Stage 2 | The individual has difficulty hearing direct conversation at close range, but can hear satisfactorily over the telephone or can hear loudly spoken speech. | ³ 35 dB |
| 3) Partial deafness Stage 3 | The individual has difficulty hearing over the telephone at ordinary intensities, but can hear amplified speech by means of hearing aids or similar devices. | ³ 55 dB |
| 4) Total deafness for speech | The individual cannot hear speech under any circumstances. | ³ 90 dB |
The value of hearing loss is strongly dependent on age and is also different for men and women. For
example, at the age of 20 years less than 1% of the individuals will have AHL ³
24 dB, whilst the percentage at 65 years is about 25%. A deviation of ±
20 dB about the nominal is considered within the normal range of hearing ([8], p.34).
Plomp, in his paper, provided the graph of the cumulative percentage of the population having a average hearing loss (AHL) greater than any given number of dB shown in figure 1 (averaged at 0.5,1 and 2 kHz).
Plomp estimated that hearing aids may be useful for AHL ³ 35 dB but stated that aids are seldom asked for unless the hearing loss is ³ 40 dB, even if they are provided free of charge.
Figure 1
Percentage of population having a hearing loss greater than any given number of dB
Gleiss records data from Sweden and Denmark stating that < 2% of the population have a hearing
aid, which corresponds to AHL > 43 dB, so agreeing well with Plomp's assertion.
Also superimposed on the graph of figure 1 is data shown in table 3 derived
from that quoted by Adrian Davis [11] from a hearing study by the MRC Institute
of Hearing Research at Nottingham University. This data used a hearing loss averaged over 0.5, 1,
2, and 4 kHz and so would be expected to show the somewhat greater loss evident in these figures (almost
10 dB).
| Hearing loss | >25 dB | > 30 dB | > 35 dB | > 45 dB | .55 dB |
| % of Adults | 16.3% | 11.0% | 7.8% | 3.7% | 2.0% |
| % of total population | 13% | 8.8% | 6.3% | 2.9% | 1.6% |
(% of total population derived assuming 20% below age of 17)
Table 3
H. Davis, in his book on abnormal hearing and deafness [12] gave some differing classifications of hearing impairment based upon average hearing loss in the speech area:
| <20 dB loss | Considered normal |
| 50 - 60 dB | Moderately hard of hearing |
| 70 - 90 dB | Severely hard of hearing |
| >92 dB loss | “Deaf” |
Using the data from the work of Beasley and Plomp, Norman Gleiss [13] was able to
relate problems with telephone communication with the percentage of the population suffering such
problems to arrive at the figures shown in table 5.
He showed that people with AHLs in the range of 24 to 34 dB, who report some difficulty in normal conversation do not have appreciable problems when using the telephone and that people with AHLs up to 54 dB can hear satisfactorily over the telephone at normal speech levels.
| Class | AHL | Problems with telephone communication | Percent of population |
| A | AHL < 24 dB | None | |
| B | 24 - 34 dB | Not appreciably | 4.1% |
| C | 35 - 54 dB | Can hear satisfactorily at normal speech levels | 2.4% |
| D | 55 - 89 dB | Have difficulties at normal levels without additional aid | 0.8% |
| E | AHL ³ 90 dB | Cannot use telephone with any acoustical aid | 0.2% |
Adrian Davis [11] states that 5% of the adult population have moderate difficulty
using the telephone and 1.8% have great difficulty. These figures are approximately equivalent to
4% and 1.4% of the whole population.
John Barnes in his paper given at the International Human Factors Symposium in 1995 [14] points out that for speech, the signal received at the ear over a typical telephone connection is some 20 to 25 dB louder than a conversation at one metre distance, depending on the conditions (reverberant or free field).The degree of amplification required by most hearing impaired people is not directly related to the degree of loss but approximates to half the hearing loss [15]. Consequently a person with 50 dB of loss will be satisfied by about 25 dB of amplification. This suggests that difficulty using the telephone would begin to be reported at hearing losses of 50 dB or so which is close to the figure of 55 dB given in the Gleiss data. Using the UK hearing loss data this 50 dB corresponds to 2% of the population which agrees remarkably well with the 1.8% reported by Adrian Davis [11].
Some general figures on hearing and other handicaps is given by Sandhu, Carruther and Delaney in
their study of demography trends carried out as part of the RACE-TUDOR survey. An extract from their
work is given in table 6.
| Country |
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| UK |
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| Begium |
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| Netherlands |
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| Italy |
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| Germany |
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| France |
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| Sweden |
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| Ireland |
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| Greece |
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| Denmark |
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| Portugal |
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| Luxembourg |
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| Spain |
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The same paper gives 2.7% of the European population (representing 8.7 million) with a hearing handicap,
presumably derived from the total of the above data.
This spread of figures could be accounted for by a range of limits for the assessment of hearing impairment with 45 dB as the mode, with the UK and Sweden using a 35 dB figure and Italy using 55 dB. Referring to Plomp's statement that hearing aids are not requested until the AHL is > 40 dB (probably equivalent to a modern 4 frequency average of nearly 50 dB) it is probable that these figures relate to the percentage national demands for hearing aids.
How can these figure be related to the figures ranging from 0.24% to 15% hearing impaired reported from other sources?
The figure of 0.24% comes from a Deutches Bundespost study in 1988-90 quoting 190,000 with "substantial to severe grades" of hearing disability out of a population of 79.7 million. This probably relates to the commonly agreed figure of 0.1 -0.2% profoundly deaf given by Frederiksen [8] and Gliess [13].
The figure at the other extreme, 15% comes from the range of "hard of hearing" given by Frederiksen [8] of 10 to 15%. This represents the just detectable onset of hearing impairment represented by a loss of 20 - 25 dB and the range covers UK and US data. This is supported by a UK study quoted by Mike Martin [16] which gives 16.1% of the UK population with a hearing loss ³ 25 dB. The figures given in table 7 are supported by the work of Davis [11] shown in figure 2.
| Age |
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| 17 - 30 |
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| 31 -40 |
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| 41 - 50 |
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| 51 - 60 |
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| 61 - 70 |
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| 71 - 80 |
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| Overall |
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Figure 2
Difficulty using the phone versus age
Thus it can be seen that as age increases, between about 14% and 30% of people over 65 will have moderate
or greater difficulty using a standard telephone, which clearly represents a large market for suitably
adapted terminals, particularly when considering the secondary market of children who may purchase
telephones that are able to be used by visiting parents.
Conclusions
Thus it can be seen that the wide range of figures makes sense. It all depends what is meant by hearing impairment.
It is possible to say with reasonable confidence that there are 0.1 - 0.2% of the population who
are profoundly deaf, cannot benefit from any acoustic aid and whose only form of telecommunication
is a textphone.
Roughly 5% of the UK population are sufficiently hearing impaired to ask for a hearing aid. In other
countries with less developed health services, this figure is closer to 3% dropping to below 2% in
some countries.
Approximately 15% of the population can be demonstrated to have some measure of hearing impairment.
All except 2% of the population could make reasonable use the telephone without additional assistance but probably up to 5% would benefit significantly by provision of a measure of amplified reception.
Of the elder population somewhere between 14% and 30% would benefit from some aid when using the telephone.
Other Handicaps
The are a number of other disabilities that create handicaps for users of the telephone. Visual impairment in its various forms, many of which are associated with ageing, is becoming more important in these days of computer aided telephony.
Loss of motor skills and strength bring with them problems when operating some telephone keypads, particularly those such as on mobile telephones with very small keys.
Changes in cognitive function affecting the speed of information processing and memory can cause problems if time outs in operating procedures are too short.
Statistics on some of these disabilities are rather sparse, but it has been stated #2 that 2% of the population of the European Community suffer from visual disability and that another 1.9% suffer from a disability affecting their upper limbs.
These handicaps can be aided by suitably directed design which can address this significant market by relatively simple features, often within the range of normal design parameters.
Sandhu [5] reported that within the EU over 37 million are disabled and nearly 69 million are elderly with 80 million being both elderly and disabled. Although his figures for the elderly may be about 5% higher than some others (he was treating elderly as being over the age of 60) these figures represent some 25% of the population, a market that that a supplier would ignore at his peril.
References:
Last updated: 19.02.2008 © Copyright reserved
