Extrapyramidal signs in normal pressure hydrocephalus: an objective assessment

Allen S Mandir¹^,2 , Jennifer Hilfiker¹ , George Thomas¹ , Robert E Minahan² , Thomas O Crawford¹ , Michael A Williams¹^,3 and Daniele Rigamonti¹

¹Johns Hopkins University, Department of Neurology and Neurosurgery, Baltimore, MD 21287, USA

²Georgetown University Hospital, Department of Neurology, 3800 Reservoir Road – PHC-7, Washington, DC 20007, USA

³LifeBridge Health Brain & Spine Institute, Adult Hydrocephalus Center, Sinai Hospital of Baltimore, Baltimore, MD, 21215, USA

author email corresponding author email

Cerebrospinal Fluid Research 2007, 4:7doi:10.1186/1743-8454-4-7


Published:	13 August 2007

Abstract

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.

Conclusion

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.