I'm not intending to dispute Paul's reply. Word doesn't really work with lines.
There are however some methods and properties associated with the activewindow object that you might use. For example, using the following code, you can scroll through a document one line at a time:
Code:
Option Explicit
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Private bStop As Boolean
Sub StopScroll()
bStop = True
End Sub
Sub StartScroll()
Dim i As Long
Dim oPage As Page
Dim j As Long
Dim oRng As Word.Range
bStop = False
For Each oPage In ActiveDocument.ActiveWindow.ActivePane.Pages
For i = 1 To oPage.Rectangles(1).Lines.Count
j = oPage.Rectangles(1).Lines(i).Range.HighlightColorIndex
oPage.Rectangles(1).Lines(i).Range.Select
Set oRng = Selection.Range
Selection.Collapse wdCollapseEnd
oRng.HighlightColorIndex = wdYellow
Doze 200 '= 1 second
DoEvents
ActiveDocument.ActiveWindow.SmallScroll Down:=1 'one line
oRng.HighlightColorIndex = j
Application.ScreenRefresh
If bStop Then GoTo lbl_Exit
Next i
Next oPage
lbl_Exit:
Exit Sub
End Sub
Sub Doze(ByVal lngPeriod As Long)
DoEvents
Sleep lngPeriod
End Sub