Battered child and unwanted pregnancy To the editor: In the exchange (Can Med Assoc J 112: 279, 1975) between Tompkins and the authors of the paper "The unwanted pregnancy" (Can Med Assoc J 111: 1093, 1974) Scott and Stone state "there certainly are, then, sufficient numbers of unwanted pregnancies resulting in unwanted infants to presume that they may make up the majority of the beaten and neglected children". In a study of over 600 abused children, Dr. E.F. Lenoski, assistant professor of pediatrics and emergency medicine, University of Southern California School of Medicine, Los Angeles, reported that 90% of the children's parents stated that they had wanted the pregnancy. B.E. BROSSEAU, MD
Bonnyville, Alta.
Results of acupuncture To the editor: The report on the 1975 annual meeting of the Royal College (Can Med Assoc J 112: 356, 1975) is misleading in the account given of the results of the, acupuncture studies performed at The Arthritis Centre in Vancouver. The report quotes me as stating that "analysis of subjective pain and tenderness did not reveal significant difference between the experimental and control group". This statement is true for only a part of one of the three experiments that were performed. The report of three controlled trials on the influence of acupuncture on the pain of rheumatic disease will be published in full in due course but the results reported at the meeting indicated a significant effect of acupuncture in each of three experiments (rheumatoid arthritis affecting the Contributions to the Correspondence section are welcomed and if considered suitable will be published as space permits. They should be typewritten double spaced and should not exceed 1½ pages in length.
hands, painful shoulder syndrome without arthritis and rheumatoid arthritis affecting the knees). Acupuncture does do something and the observations we have made are compatible with the relief of pain. L.H. TRUELOVE, BM, FRCP[C]
The Arthritis Centre 895 West 10th Ave. Vancouver, BC
Painful shoulder syndrome
uncover the temporal relation between PSS and depression retrospectively, but this approach is open to many errors, particularly if the patients were depressed at the time of interview. Dr. Tyber's findings are collected in Table I. He interprets these figures as indicating that "depression preceded or was simultaneous with the development of PSS in 50% (13/26) of patients", and this interpretation led him to speculate that depression might be etiologically implicated in PSS. By the same process one could say that PSS preceded or was simultaneous with the development of depression in 62% (16/26) of patients, leading to the speculation that PSS might be causally related to depression. However, considering the inaccuracy of the approach (as well as of the figures themselves) it is difficult to draw any conclusion. If one does consider the possibility of PSS causing depression, a simpler explanation for the association, as well as of the nocturnal exacerbation of pain, can be suggested. The pain of this syndrome is known to be positionally related (this aspect was used in the clinical grading), so the worsening of pain at night may well be related to the position in which the patient sleeps. This has in fact been commented on by patients; they may, for example, wake up with an intense pain after having rolled over from a painfree position onto their shoulder. The reason why the exacerbation of pain at Table I-Relation between depression and the painful shoulder syndrome in the test group
To the editor: The article "Treatment of the painful shoulder syndrome with amitriptyline and lithium carbonate" by M.A. Tyber (Can Med Assoc J 111: 137, 1974) highlights a number of problems that can arise if patients who have been instrumental in their own selection (to a hospital, clinic or private practice) are used for the study of disease interrelations. It also illustrates some of the difficulties encountered when therapeutic measures are evaluated. In commenting on Dr. Sullivan.s subsequent suggestion of an association between the painful shoulder syndrome (PSS) and diabetes,1 Dr. Chaiton2 discussed "Berkson's fallacy": when hospital, clinic or private patients are used for studying disease interrelations spurious associations can arise through the interplay of various selection factors at work on the different diseases. This phenomenon must also be considered in relation to Dr. Tyber's study. For example, patients with both P55 and depression may be more likely to reach Dr. Tyber than those with P55 alone. If the selection of other types of patients (i.e. those used as controls) is in any way different, then PSS and Tb. of patients depression may appear more strongly related than they in fact are. Patients with depression and PSS Depression preceded PSS 4 An association between two diseases Depression and PSS simultaneous 9 found by prevalence data does not reDepression followed PSS 7 veal whether disease A caused disease Indeterminate 6 B, B caused A, or whether they were Total 26 8 both caused by another factor. In Dr. Patients with PSS only Tyber's study an attempt was made to All patients in test group 34
CMA JOURNAL/MAY 3, 1975/VOL. 112 1039
Bonnyville, Alta.
Results of acupuncture To the editor: The report on the 1975 annual meeting of the Royal College (Can Med Assoc J 112: 356, 1975) is misleading in the account given of the results of the, acupuncture studies performed at The Arthritis Centre in Vancouver. The report quotes me as stating that "analysis of subjective pain and tenderness did not reveal significant difference between the experimental and control group". This statement is true for only a part of one of the three experiments that were performed. The report of three controlled trials on the influence of acupuncture on the pain of rheumatic disease will be published in full in due course but the results reported at the meeting indicated a significant effect of acupuncture in each of three experiments (rheumatoid arthritis affecting the Contributions to the Correspondence section are welcomed and if considered suitable will be published as space permits. They should be typewritten double spaced and should not exceed 1½ pages in length.
hands, painful shoulder syndrome without arthritis and rheumatoid arthritis affecting the knees). Acupuncture does do something and the observations we have made are compatible with the relief of pain. L.H. TRUELOVE, BM, FRCP[C]
The Arthritis Centre 895 West 10th Ave. Vancouver, BC
Painful shoulder syndrome
uncover the temporal relation between PSS and depression retrospectively, but this approach is open to many errors, particularly if the patients were depressed at the time of interview. Dr. Tyber's findings are collected in Table I. He interprets these figures as indicating that "depression preceded or was simultaneous with the development of PSS in 50% (13/26) of patients", and this interpretation led him to speculate that depression might be etiologically implicated in PSS. By the same process one could say that PSS preceded or was simultaneous with the development of depression in 62% (16/26) of patients, leading to the speculation that PSS might be causally related to depression. However, considering the inaccuracy of the approach (as well as of the figures themselves) it is difficult to draw any conclusion. If one does consider the possibility of PSS causing depression, a simpler explanation for the association, as well as of the nocturnal exacerbation of pain, can be suggested. The pain of this syndrome is known to be positionally related (this aspect was used in the clinical grading), so the worsening of pain at night may well be related to the position in which the patient sleeps. This has in fact been commented on by patients; they may, for example, wake up with an intense pain after having rolled over from a painfree position onto their shoulder. The reason why the exacerbation of pain at Table I-Relation between depression and the painful shoulder syndrome in the test group
To the editor: The article "Treatment of the painful shoulder syndrome with amitriptyline and lithium carbonate" by M.A. Tyber (Can Med Assoc J 111: 137, 1974) highlights a number of problems that can arise if patients who have been instrumental in their own selection (to a hospital, clinic or private practice) are used for the study of disease interrelations. It also illustrates some of the difficulties encountered when therapeutic measures are evaluated. In commenting on Dr. Sullivan.s subsequent suggestion of an association between the painful shoulder syndrome (PSS) and diabetes,1 Dr. Chaiton2 discussed "Berkson's fallacy": when hospital, clinic or private patients are used for studying disease interrelations spurious associations can arise through the interplay of various selection factors at work on the different diseases. This phenomenon must also be considered in relation to Dr. Tyber's study. For example, patients with both P55 and depression may be more likely to reach Dr. Tyber than those with P55 alone. If the selection of other types of patients (i.e. those used as controls) is in any way different, then PSS and Tb. of patients depression may appear more strongly related than they in fact are. Patients with depression and PSS Depression preceded PSS 4 An association between two diseases Depression and PSS simultaneous 9 found by prevalence data does not reDepression followed PSS 7 veal whether disease A caused disease Indeterminate 6 B, B caused A, or whether they were Total 26 8 both caused by another factor. In Dr. Patients with PSS only Tyber's study an attempt was made to All patients in test group 34
CMA JOURNAL/MAY 3, 1975/VOL. 112 1039
