The Psalm is still widely sung but it has some particular lines which made the researchers take notice. Here they are in modern English from the New International Version of the bible:
If I forget you, Jerusalem,
may my right hand forget its skill.
May my tongue cling to the roof of my mouth
if I do not remember you,
if I do not consider Jerusalem
my highest joy.
This seems to describe some clear physical symptoms but the bible has numerous versions all of which have different translations and even in their early versions do not always agree on the exact wording.
As a result the researchers looked at Spanish, English, German, Dutch, Russian, Greek, and Hebrew versions to examine the consistency of the text and the variations in description of these curious physical effects. The combined description includes:
If I forget of you, oh Jerusalem, my right hand (my right side) shall dry, be paralyzed, loose its ability, its dexterity… That my tongue shall stick (shall be weakened, arrested) to my palate (in my throat), if I remember you, if I do not permit Jerusalem to be my greatest joy (if I do not sing of Jerusalem as my greatest joy)
Both right-sided paralysis and loss of expressive speech are clear symptoms of a stroke of the left middle cerebral artery, where the blood flow is blocked – leading to the death of the surrounding brain tissue, suggesting that the Psalm may be wishing these effects on people who forget the importance of Jerusalem.
The powerful nature of the wish is perhaps explained by the fact that the Psalm is widely believed to have been written as a lament by Jewish people exiled after the conquest of Jerusalem by the Babylonians in 586 BCE.
But why these specific symptoms are mentioned may have more to do with ancient beliefs about stroke itself.
The reason the condition is still called stroke is because people originally believed that it was a result of being ‘struck down’ by God.
The Psalm still remains popular and the opening lines “By the rivers of Babylon…” have spawned a cottage industry in bad pop songs most of which miss out the lines concerning stroke.
However, the track Jerusalem by Jewish reggae hip-hop maestro Matisyahu does focus on this part of the Psalm, which he mashes-up along with lyrics from Matthew Wilder’s Break My Stride.