Table 1.

Comparison of different methods of sleep deprivation

Parameters compared/Methods	Flowerpot method	Hand arousal method	Treadmill arousal method	Pendulum method	Multiple-platform method	Rotating disk-over-water method
First used Sleep-state specificity	Jouvet et al42 REMSD	Dement4 REMSD or total sleep deprivation	Ferguson and Dement47 REMSD or total sleep deprivation	van Hulzen and Coenen48 Total sleep deprivation	van Hulzen and Coenen49 REMSD	Bergmann et al52 REMSD or total sleep deprivation
Advantages	• No surgical/external interference • Effective for selective REMSD for long term (more than 48 h) • Continuous monitoring not required • Suitable controls (LPC, REC, etc.) can be designed • Many animals can be deprived simultaneously • Experimental and controls can be carried out simultaneously in the same environment	• Effective for short periods of deprivation • Subjects maintained in normal environment • Applicable to both humans and animals	• Short-term deprivation can be done	• No external/surgical intervention	• Movement restriction overcome • No social isolation	• Deprivation can be carried out for longer duration
Limitations	• Movement restriction • Altered external environment • Isolation control to be carried out • Maintenance of appropriate ratio of platform size to body weight is crucial, which was not adhered to in many studies50,62 • Man studies did not carry out adequate (LPC, REC, etc.) controls62	• Long-term deprivation not effective as frequency of awakenings increases leading to total sleep deprivation • Awakening threshold keeps increasing with increased duration of deprivation • Continuous monitoring is required • Involves surgical intervention and elaborate automated computer-based experimental setup	• Elaborate setup needed • External environment altered for animals • No free supply of food and water available • Long-term deprivation not possible • May be invasive • Difficult to design suitable controls	• No free excess to food and water • External environment altered • Several animals cannot be simultaneously deprived • Difficult to design suitable controls	• Disturbance of animals among themselves (unpublished data, 2018) • Appropriate ratio of platform size to body weight was not maintained50,62,63 • Large-platform controls not used63	• Elaborate computer-based setup required • Surgical implants involved • Altered environment • Difficult to design suitable controls • Several animals cannot be simultaneously deprived

Notes: Considering all the advantages and disadvantages, the platform method is the best as appropriate controls can be carried out and experimental as well as controls can be carried out simultaneously. Maintenance of body weight-to-platform size ratio is most important. The multiple-platform method apparently overcomes the social isolation limitation of the single platform; however, practically awake rats (while huddling together) often keep disturbing each other, and all the rats probably are deprived to various degrees (unpublished data, 2018). In many of the experiments using flowerpot and multiple-platform methods, the body weight-to-platform size ratio was not maintained. Often, LPC and REC controls were not carried out; also, it was not shown if the deprivation-induced effects could be prevented by using antagonist/blocker of specific factor(s) induced by REMSD.

Abbreviations: REMSD, rapid eye movement sleep deprivation; LPC, large-platform control; REC, recovery group.