I had the DTI MRI, it comes back clean.
I'm very sad because now the doctors will use it as an evidence to say that my problem is psychological.

A clean DTI MRI does not rule out an injury. A positive DTI MRI is very accurate but false negatives are not uncommon. A healed injury can still cause symptoms without showing the DTI abnormalities.

Maybe the language issue is a problem but the way you explain your symptoms leaves issues to consider. You come across as far more anxious than objectively aware. It is very difficult to self-diagnose most of the symptoms you have stated other than headaches. Reading about concussions can trigger an over concern for such symptoms such that every time one forgets, they attribute it to the concussion.

A professionally administered Neuro Psychological Assessment is considered the gold standard for diagnosing neurological deficits.

Yeah language is surely a problem, hovewer I don't think that my current symptoms are due to the concussion but due to the antipsychotics.
Mi cognitive struggles are surely there and real, I can't understand simple concepts and I slur my speech unable to formulate coerenth sentences.
The psychiatris has prescribed me a neuro psychological assesment.

I think the NP test is only good for those with more moderate to severe TBI’s. So called mild TBI’s fly under the radar and get labeled as depressed or anxious.

Danielson complains of memory and cognitive issues. If he has them, they would show on an NP. If he is just overly attentive to normal memory or thought struggles, his scores will be in the normal ranges.

NPs don't diagnose TBI intensity. They just indicate brain dysfunction. Even the experts do not understand why a person can be out cold for hours and have no NPA diagnosed dysfunction and another can have a minor ding and have serious NPA diagnosed dysfunctions.

Hi, I'm asking for your help because there is something that I don't understand and that seems suspicious to me, altough I'm not able to explain it well.
Basically today my mother take the appointment for the neuropshycological tests, but my appointment is at 16.00 PM, which seems odd to me since I have read that the test should take a whole day.
I have fear that they are going to have some brief and very superficial test not accurate enough to show my symptoms and dysfunctions.
What should I expect? and what can I do to make sure that they are going to perform tests useful for my situation?

Some doctors do a pre test to determine what sub tests to use. There are many sub tests in a neuro psychological assessment. Some will break the test up over different days.

I had a short version that only took 90 minutes plus three that took 4 hours or more.

It does not sound like you have much control over what they are going to do. Relax and just do as they ask.

It's difficult to relax and trust them since it seems that nobody is interested in my situation or in my health.
I wanna be sure that they are going to do something that can detect my mild cognitive impairment, I don't want to spend money to do some superficial test that will only tell me if I'm at dementia level (which I already know I am not) or not.

Trust me, get your hormones tested. I had to do 5 hour STIM test. My MRI with DTI was fine but I just found out I have hypopituarism from the STIM test. My Testosterone levels are fine so even a basic hormonal panel would have missed that I’m deficient in growth hormone.

There are maybe a few endocrinologist in the U.S. that are aware of the hormone/TBI relationship. I’d do whatever you can to find one.

I had the same problem. I have hypopituitarism the result of a whiplash injury sustained in a rear-end accident (someone ran in to me). My growth hormone levels were at 0.03, or somewhere around there. I almost was not producing growth hormone. For two years after my concussion, it hardly healed because the hypopituitarism issue was not diagnosed. I'm much better now, but I still suffer from some of the symptoms.

They've had me on growth hormone injections, and my insurance has covered it. Unfortunately, due to me making a comment, the result of the effects of the brain injury, I have lost my job and will be losing my insurance soon. Growth hormone is insanely expensive. Genotropin is $1600 per month without insurance. I don't know what I'm going to do.