This thread is even older now!! - but I've just stumbled across this forum and there are a couple of things I would like to add into the conversation re collapsing EIC clears and carriers.

The first is a comment which can be found in a recent report by the International Veterinary Epilepsy Task force, in which they state that there is probably more than one form of EIC -

"Several studies suggest the existence of another and “DNM-1-independent” EIC condition in Labrador Retrievers, as some of the EIC-affected Labrador Retrievers are negative or heterozygous for the DNM1-gene mutation (approximately 15–30 % of EIC affected Labrador Retriever) [97], [98]. Hence, two distinct terms have gained acceptance for Labrador Retrievers: d-EIC (homozygous DNM1-gene mutation) and non-d-EIC (negative or heterozygous for the DNM1-gene mutation) [30], [97], [98]. Apart from a suspected diverse genetic background for the latter two EIC types, clinical differences between d-EIC and non-d-EIC have been observed. However, in general, and in contrast to seizures, EIC-episodes are induced by strenuous exercise. Contrary to epileptic seizures muscle tone is initially decreased in the affected limbs and consciousness remains preserved in more than 80 % of the Labrador Retriever with d-EIC. Another study also reported a wide-based pelvic limb stance, crouched posture and falling to the side during d-EIC"

And then I would also like to add that my EIC carrier lab suffers from collapsing episodes which have been diagnosed as paroxysmal dyskinesia. In the early years all episodes were triggered by excitement/over-exercise/startle - but now they happen without any obvious trigger. This is part of an article about PD which was recently submitted to the Health Committee of the UK Labrador Breed Council -

PAROXYSMAL DYSKINESIA IN THE RETRIEVER LABRADOR BREED
Paroxysmal Dyskinesia is an episodic neurological condition which is increasingly being diagnosed in Labradors. It is commonly mistaken for an epileptic seizure disorder by vets and owners alike, and so it is important to understand how Paroxysmal Dyskinesia differs to epileptic seizures or fits so that it can be quickly recognised.
Paroxysmal Dyskinesia is a movement disorder and is thought to be genetic in nature (the mode of inheritance has not as yet been established). During an episode of dyskinesia the dog is fully alert and will attempt to obey commands, although he/she may have no control of limbs. Dogs remain fully conscious throughout the episode, there is no loss of bladder/bowel control, and no excessive salivation. This makes the episodes very different to epileptic seizures in which salivation, urination and a loss of awareness are expected. Episodes can sometimes be brief and fairly mild with the dog showing just a little bit of unsteadiness or incoordination of the limbs (possibly described as a “funny turn”). However other Labradors have very severe episodes despite being fully aware which can cause full collapse and involve the entire body, which is very distressing to both dog and owner. During these extreme episodes very severe muscle spasms may occur (which may possibly be painful). While some mild episodes may be fairly short, the severe episodes can last well over an hour. Once the episode is over recovery is immediate – the dog will get to its feet and almost instantly revert back to normal. There is no “aura” before the episode or post-ictal signs following the episode, which again makes them distinct to epileptic seizures in which a prolonged period of abnormal behaviour may be seen following a fit. Dogs are completely normal in between episodes and show no problems at all until the next episode occurs. Frequency, severity, and length of episodes can vary dramatically between dogs but also within individuals. Importantly, Paroxysmal Dyskinesia is not thought to influence life expectancy, with affected dogs often living long, full lives.
Some Labradors can have just a few episodes and then appear to go into complete remission (having no further episodes – or just very occasional ones), but others experience these episodes for the remainder of their lives with a frequency of anything from one episode every year to several per week. Dogs mostly begin having episodes of Paroxysmal Dyskinesia while young, often experiencing their first episode by the age of two. In some Labradors the episodes can be triggered by excitement, a sudden burst of energy, or startle – but others appear to have episodes without any apparent trigger.
Labradors were first identified at the Animal Health Trust as having Paroxysmal Dyskinesia about fifteen years ago, and neurologists are now diagnosing more dogs as having the condition. However until recently there has been very little awareness of Labrador Dyskinesia among the general veterinary profession. It is possible that Labradors with Paroxysmal Dyskinesia may be misdiagnosed as having epilepsy. Labradors with dyskinesia do not usually respond to antiepileptic drugs and at this time no treatment has been found to help dogs with the condition. Therefore recognising the condition is important so that Labradors are not needlessly given long-term antiepileptic drugs that may have little effect in controlling the episodes.
Recently, neurology specialists Mark Lowrie and Laurent Garosi began a study into this movement disorder in Labradors with a view to correctly identifying the condition so that accurate diagnosis can be made, raising awareness of Paroxysmal Dyskinesia within the veterinary profession and the public, and hopefully finding a treatment which may help these dogs. The initial stage of the study has now been completed and an article written by Mark Lowrie was published in the July 2016 edition of The Veterinary Journal

https://www.researchgate.net/publication/297891552
Natural_history_of_canine_paroxysmal_movement_disorders_in_Labrador_retrievers_and_Jack_Russell_terriers..

The research project is ongoing.

This is a link to a video which shows a Labrador having an episode of Paroxysmal Dyskinesia
https://www.youtube.com/watch?v=MdifQO2qevg