CORRESPONDENCE

DIABETIC AUTONOMIC NEUROPATHY

To the Editor:

With interest, I read the article by Niakan et al, “Diabetic

Autonomic Neuropathy.“’ These authors concluded by stating that

“diabetic autonomic neuropathy has received less attention than

other diabetic complications.” While this may be true, their idiosyn-

cratic citation of the published literature on the topic raises the

possibility that more attention has been paid to it than they are

aware of. For example. Niakan et al speculate that immunologic

disturbances may play a role in diabetic autonomic neuropathy

without mentioning several relevant papers, or the previously pub-

lished hypothesis that immunologic mechanisms may be involved in

the pathogenesis of the disorder (possibly as a result of insulin

antibodies acting as antinerve growth factors).2 This hypothesis

appeared in an extensive review of the physiologic investigation of

diabetic autonomic neuropathy in which there was a systematic

consideration of a series of publication?’ dealing with cardiovascu-

lar dysregulation in patients with diabetes mellitus and the possible

pathophysiologic causes of the abnormalities. In that review, and

elsewhere,” it has been pointed out that measurement of heart rate

alone as an index of response to any particular stimulus may be

misleading. Against this background, the perpetuation by Niakan et

al of the naive belief that measuring heart rate changes evoked by a

Valsalva’s maneuver permits reliable detection of diabetic auto-

nomic neuropathy is misleading. Niakan et al’ deal also with the

literature on impotence in a partial fashion, failing to point out that

the earlier studies have been extended to include cardiovascular

testing and the monitoring of nocturnal erections during REM sleep

in the same patients to better define the occurrence of psychogenic

impotence.‘3

If Niakan et al based their review on citations in the literature, it

could be argued that the aforementioned omissions were a conse-

quence of the fact that parochiality is rife amongst workers in the

field of diabetic autonomic neuropathy. However, Niakan et al also

failed to mention the important publications of Wieling et al’c*O that

are well-cited in the literature. As a result, this review lacks

objectivity and raises the question-what purpose was it meant to

serve?

Terry Bennett, PhD Department of Physiology and Pharmacology

Medical School

Queen’s Medical Centre

Clifton Blvd

Nottingham, NG7 2UH England

REFERENCES

1. Niakan E, Harati Y, Comstock JP: Diabetic autonomic neu-

ropathy. Metabolism 35:224-234, 1986

2. Bennett T: Physiological investigation of diabetic autonomic

neuropathy, in Bannister R (ed): Autonomic Failure. Oxford,

Oxford University, 1983, pp 406-436

3. Bennett T, Hosking DJ, Hampton JR: Cardiovascular control

in diabetes mellitus. Br Med J 2:585-587, 1975

4. Bennett T, Hosking DJ. Hampton JR: Baroreflex sensitivity

and responses to the Valsalva manoeuvre in subjects with diabetes

mellitus. J Neurol Neurosurg Psychiatry 38:178-183, 1976

5. Bennett T. Hosking DJ, Hampton JR: Cardiovascular

responses to apnoeic face immersion and to mental stress in diabetic

subjects. Cardiovasc Res 10: 192-l 99, 1976

6. Bennett T, Hampton JR, Hosking DJ, et al: Continuous

monitoring of heart rate and activity patterns in diabetic subjects:

Comparison with clinic investigations. Br Med J 1:1250-1251,

1976

7. Bennett T, Fentem PH, Fitton D, et al: The assessment of

vagal control of the heart in diabetes: Measures of R-R interval

variation under different conditions. Br Heart J 39:25-28, 1977

8. Bennett T, Farquhar IK, Hosking DJ. et al: Assessment of

methods for estimating autonomic nervous control of the heart in

patients with diabetes mellitus. Diabetes 27:1167-l 174, 1978

9. Bennett T, Hosking DJ, Hampton JR: Cardiovascular reflex responses to lower body negative pressure in normal subjects and in

patients with diabetes mellitus. Cardiovasc Res 13:31-38, 1979

10. Bennett T, Hosking DJ, Hampton JR: Vasomotor responses to the Valsalva manoeuvre in normal subjects and in patients with

diabetes mellitus. Br Heart J 42:4222428, 1979

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1980

12. Bennett T: Are cardiovascular reflexes a useful means of

assessing autonomic neuropathy? Med Interne 4:55-63, 1983

13. Hosking DJ, Bennett T, Hampton JR, et al: Diabetic impo-

tence: Studies of nocturnal erection during REM sleep. Br Med J

2:1394-1396,1979

14. Van Brederode JFM, Wieling W, Borst C, et al: The immedi-

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base for cardiac vagal neuropathy. Diabetologia 22: 163-I 66, 1982

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of initial heart rate response to postural change. Am J Physiol

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1983

18. Wieling W, Borst C, Van Dongen Torman MA, et al: Relationship between impaired parasympathetic and sympathetic

cardiovascular control in diabetes mellitus. Diabetologia 24:422-

427, 1983

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1078 Metabolism, Vol 35, No 11 (November), 1986: pp 1078-1079