Background.  Previous studies showed that with induced hypoglycaemia the PT. had a marked increase in power (amplitude), (cm/sec²)²) of 100 to 300% and correlates with the adrenaline response to hypoglycaemia in type 1 diabetes and non-diabetic subjects. The response of the PT during sleep, physical activity, routine daily living and medication is unknown.

Subjects and Methods. The PT. was recorded at the wrist by a data-logger, Mega Electronics ME 6000, worn continuously. The vertical responses are reported as % increase in power from base line.  CGMS with Medtronic Guardian Real-Time. Subject 8 destroyed the data-logger.

7 Type 1 diabetics (M4, F3 mean age 51, duration diabetes 26yrs, weight 81kg, HbA1c 8.9%, 2 hypoglycaemic unaware) and 1 non- diabetic were studied for 2/3 days continuously giving 18 days of recording. 2 subjects undertook heavy physical activity (concreting, fire man physical training), one male partook of vigorous sexual intercourse, 2 hours later becoming hypoglycaemic. 1 subject took venlafaxine 75mg an SNRI giving her severe hypoglycaemic unawareness. Not included in results.

Results.  14 episodes of hypoglycaemia (glucose < 4mmol and power increase > 50%) occurred, 7 during sleep.    Initial power increase (> 25%) occurred at mean glucose level of 6.1mmol, mean increase in peak power was 90% above baseline at glucose 3.4mmol taking 170 minutes to occur, duration of peak power 103 minutes. There was no false positive or false negative response of the PT to hypoglycaemia. Correlation of glucose to power p>0001.  Similar responses occurred between hypoglycaemic aware and unaware subjects.

Findings. The PT did not change with sleep, daily physical activity, anti-hypertensives, lipid lowering drugs. 

Setraline markedly altered the hypoglycaemic PT response. It decreased tremor base line from 11 to 4, delayed onset of power response to 300 minutes and prolonged duration of power response to 240 minutes.

Sexual intercourse in a male increased power response (100%) but hypoglycaemia caused a greater increase. (150%)

Conclusions. There is a close and predictable response of the PT. with hypoglycaemia. This response could be used as a non-invasive indicator of hypoglycaemia.

Hypoglycaemic responses to psychotropics need further elaboration.