The value of electrodiagnostic consultation for patients with upper extremity nerve complaints: a prospective comparison with the history and physical examination.
OBJECTIVE
To determine whether electrodiagnostic testing changes diagnostic certainty compared with a detailed history and physical examination, and whether interactions between medical information, the extent of testing, and diagnostic certainty imply a need for advanced medical knowledge on the part of the tester.


METHODS
Prospective observation.


METHODS
University orthopedic department and small community hospital electrodiagnostic laboratories.


METHODS
Two hundred fifty-five consecutive referrals for upper extremity nerve complaints.


METHODS
Diagnosis, diagnostic confidence, and severity of neurologic lesion were coded after standardized history and physical and after electrodiagnostic testing.


RESULTS
Electrodiagnostic testing substantially altered 42% of diagnoses, confirmed 37%, and did not clarify 21%. The extent of testing correlated with the size of the differential diagnosis, the number of previous hospitalizations, and the number of other medical problems. Confidence in final diagnoses correlated positively with severity of the lesion, but negatively with the size of the differential diagnosis and the number of painful body areas. Hospitalizations and medical problems also tended towards negative correlations.


CONCLUSIONS
This study, in which all electrodiagnostics, histories, and physical examinations were performed by a single physician, suggests that electrodiagnosis substantially alters clinical impressions in a large percentage of patients. The complex relationship between clinical information, the extent of testing, and final diagnostic certainty suggests that specialized medical knowledge is required for accurate electrodiagnosis.
Haig
A J
AJ
Department of Physical Medicine and Rehabilitation, The University of Michigan, Ann Arbor 48109-0042, USA.
Tzeng
H M
HM
LeBreck
D B
DB
D000328:Adult; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis*; D002983:Clinical Competence / Q000592:standards; D004576:Electromyography / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008487:Medical History Taking / Q000592:standards*; D008875:Middle Aged; D009460:Neurologic Examination / Q000592:standards*; D010810:Physical and Rehabilitation Medicine; D011446:Prospective Studies; D011843:Radiculopathy / Q000175:diagnosis*; D012017:Referral and Consultation / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017769:Ulnar Nerve Compression Syndromes / Q000175:diagnosis*