Long term propecia use lead to congnitive & speech disorders?

My main question is - can long term propecia use for MPB cause cognitive & speech disorders due to continued suppression of 5 Alpha Reductase Type II enzyme in the Spinal Cord? A logic I cam across on the net - please comment:

Dihydroprogesterone -> Tetrahydroprogesterone (Allopregnanolone) & Dihydrodeoxycorticosterone -> tetrahydrodeoxycorticosterone are catalyzed by an enzyme called 3-alpha hydroxysteroid dehydrogenase as a further metabolisis of 5AR II in spinal cord. Now by inhibiting 5AR II, Finasteride definitely inhibits allopregnanolone production in spinal chord motor neurons where mainly 5AR2 is present and also reduces allopregnanolone levels in the brain and other parts of the CNS since these parts are dependent on peripheral 5AR2 conversion of progesterone to dihydroprogesterone which is then converted to allopregnanolone by 3-alpha HSD.
Metabolic pathways of progesterone is vital of myelination and other functions in CNS. So when 5AR type 2 is inhibited by finasteride, there will be a negative effect of myelination there. The most worrying long term effect of this inhibition is demyelination of the motor neurons of the spinal chord. Sub-acute combined degeneration of the spinal cord secondary to pernicious anaemia can lead to anything from slight peripheral nerve damage to severe damage to the central nervous system affecting speech, balance and cognitive awareness. When myelin degrades, conduction of signals along the nerve can be impaired or lost and the nerve eventually withers.

This is loosely the logic. Please comment and help me out as I am freaking out big time about it because I have been using Propecia for quite some time now & have also experienced mild instances of 'Brain Fog'. Please also advice on a future strategy to check my status regarding this. Thanks a ton in advance!