Extrapyramidal signs in normal pressure hydrocephalus: an objective assessment.
BACKGROUND
Beyond the classic Normal Pressure Hydrocephalus (NPH) triad of gait disturbance, incontinence, and dementia are characteristic signs of motor dysfunction in NPH patients. We used highly sensitive and objective methods to characterize upper limb extrapyramidal signs in a series of NPH subjects compared with controls. Concentrated evaluation of these profound, yet underappreciated movement disorders of NPH before and after techniques of therapeutic intervention may lead to improved diagnosis, insight into pathophysiology, and targeted treatment.


METHODS
Twenty-two (22) consecutive NPH patients and 17 controls performed an upper limb motor task battery where highly sensitive and objective measures of akinesia/bradykinesia, tone, and tremor were conducted. NPH subjects performed this test battery before and more than 36 h after continuous CSF drainage via a spinal catheter over 72 h and, in those subjects undergoing permanent ventriculo-peritoneal shunt placement, at least 12 weeks later. Control subjects performed the task battery at the same dates as the NPH subjects. Statistical analyses were applied to group populations of NPH and control subjects and repeated measures for within subject performance.


RESULTS
Twenty (20) NPH subjects remained in the study following CSF drainage as did 14 controls. NPH subjects demonstrated akinesia/bradykinesia (prolonged reaction and movement times) and increased resting tone compared with controls. Furthermore, the NPH group demonstrated increased difficulty with self-initiated tasks compared with stimulus-initiated tasks. Following CSF drainage, some NPH subjects demonstrated reduced movement times with greater improvement in self- versus stimulus-initiated tasks. Group reaction time was unchanged. Resting tremor present in one NPH subject resolved following shunt placement. Tone measures were consistent for all subjects throughout the study.


CONCLUSIONS
Clinical motor signs of NPH subjects extend beyond gait deficits and include extrapyramidal manifestations of bradykinesia, akinesia, rigidity, and propensity to perform more poorly when external cues to move are absent. Objective improvement of some but not all of these features was seen following temporary or permanent CSF diversion.
Mandir
Allen S
AS
Johns Hopkins University, Department of Neurology and Neurosurgery, Baltimore, MD 21287, USA. asm42@gunet.georgetown.edu.
Hilfiker
Jennifer
J
Thomas
George
G
Minahan
Robert E
RE
Crawford
Thomas O
TO
Williams
Michael A
MA
Rigamonti
Daniele
D
Clin Neurophysiol. 2000 Sep;111(9):1678-86
10964082
Mov Disord. 1997 Jan;12(1):53-60
8990054
Rinsho Shinkeigaku. 2002 Feb;42(2):131-5
12424962
Eur Neurol. 1975;13(3):189-94
125202
Surg Neurol. 1976 Mar;5(3):187-210
1257894
N Engl J Med. 1965 Jul 15;273:117-26
14303656
J Cereb Blood Flow Metab. 2004 Jan;24(1):17-23
14688613
Brain. 2004 May;127(Pt 5):965-72
15033897
Brain. 2004 May;127(Pt 5):947-8
15111447
J Cereb Blood Flow Metab. 2004 May;24(5):579-87
15129190
Neurol Clin. 1992 May;10(2):451-69
1584184
Acta Pathol Jpn. 1987 Jan;37(1):97-110
3577765
Postgrad Med J. 1987 Feb;63(736):113-5
3671237
Arch Neurol. 1986 Jan;43(1):34-8
3942511
Lancet. 1972 Dec 16;2(7790):1291-2
4117815
Mov Disord. 1994 Sep;9(5):508-20
7990846
Neurology. 1993 Mar;43(3 Pt 1):500-5
8450990
Scand J Rehabil Med. 1995 Dec;27(4):205-9
8650504
J Neurol Neurosurg Psychiatry. 2001 Mar;70(3):289-97
11181848