Sleep issues are a HUGE topic of frustration and concern for parents of sensory kiddos.  From the child requiring extensive help in falling asleep, to staying asleep, to the 2am "play time", and the morning grumpy pants.   

Sleep effects the whole darn family...possibly the sibling who shares a room, or even in a separate room and of course at least one parent.  We ALL need sleep, so when our little precious sensory kiddo isn't sleeping, it affects the whole family.  And the biggest problem is the snowball effect.  When any of us do not get enough sleep it impacts mood, behavior, and self-regulation overall.  And then as always, the results are magnified for a sensory kiddo. And for the parent of the child, this state of dysregulation (irritability, mood swings, impatience, etc)  from lack of sleep impacts that child's state of regulation as well.  It's a double whammy.

As a therapist, I have always wanted to find that cure all for families and the sure ticket to sleep...but unfortunately I do not think that single ticket is out there.  BUT I DO think there can be a combination of tickets which can work...but here's the kicker...those tickets may change on a daily basis.  I am going to list some possible solutions as well as factors which can impact the sleep/wake cycle.  So it is up to you as a parent to consider each factor as well as some trial and error when it comes to what works and what doesn't seem to work.  PLEASE try not to get discouraged if something doesn't work or if an idea might work one night and not the next.  I personally know the struggles and I also feel I do understand the frustration and extreme challenge this can create from 20 years of helping families cope and find solutions to SLEEP.

The ENTIRE day can impact the ability to sleep at night.
Sensory kiddos need an enriched sensory diet every single day...including vestibular, proprioception, and tactile activities.  This is what helps their little nervous systems maintain ready state and self-regulation.  If the child has had more than 1-2 hours of screen time that day (this includes computer, TV, video games, hand held devices) then they were deprived of the important sensory nutrition in which their brain needed.  Now on the other hand, if the child was involved in some type of over-stimulating sensory activity that day this can also impact the ability to sleep (like a big social event or new challenging multi-sensory experience).  It is so important to find that balance!

If a child gets to the point of exhaustion or  "overly tired" it can back fire on the nervous system.
Once again, this requires finding a balance and as the parent knowing when enough is enough for your child. Being aware of the fact that your child can not handle as much social stimulation or partying as perhaps another child.  And not just dragging the child along to social events or play dates which may really be more for the parent.  Sorry...had to say it. 

Nutrition is a HUGE factor!
Proper nutrition throughout the day can significantly impact the ability to sleep at night.  Of course I know this one can be difficult to achieve, especially for our picky sensory kiddos.  But being creative and also aware of everything the child is consuming in a day is possible.  The biggest factors to keep in mind. 1. plenty of protein  2. limit the carbs and sugars  3.  limit the preservatives, additives, and dyes  3. plenty of fruits and vegetables 4. Of course no caffeine for a child and keeping in mind that cocoa and other forms of chocolate have enough caffeine to impact the ability to fall asleep.

Medicine, reflux, and possible sleep apnea need to be considered.
If at all possible, refrain from any medications to help with sleep.  I know this is often recommended by doctors, but with my experience this is not the solution, instead it often leads to side effects and new issues. For a child with SPD, medications further disrupt the processing in the brain.  

Reflux is an issue which can impact the ability to sleep.  This should be discussed and ruled out or addressed with your child's doctor.

If the child snores or seems to make a lot of noise at night, a sleep study should be considered.  I think it is always important to discuss the sleep difficulties with the child's doctor...and bring up or request a sleep study to rule out or to address sleep apnea. 

Before bedtime sensory tools and strategies:
(Keep in mind that this will likely be a trial and error process, unless you strike gold and the first sensory strategy you try is the ticket. )  You can try a combination of these ideas, they are in no way going to over-stimulate your child.  It just may take more than one idea or an alternate idea the next day.

Deep pressure touch to arms and legs, also called hand hugs or squeezes.  

A weighted blanket or heavy quilt folded up to increase weight and pressure. Tight fitting pajamas or compression clothing at bedtime are great too. 

Be sure the room is free of distractions, light, or clutter.  White noise or soft instrumental music is also a great tool.  Sometimes a humidifier works as well.  If possible, have the child sleep in their own space...even creating a nice cozy cave in a big walk in closet or possibly in a play tent filled with pillows and blankets is a great place for sleep.  Canopy beds or the bottom bunk of a bunk bed can be helpful as well, sensory kids like that defined and cozy space factor.