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Late onset idiopathic aqueductal stenosis (IAS) may become manifest clinically either by headaches or by hydrocephalic symptoms such as gait disturbance, urinary urge, and cognitive impairment.1 Rarely, patients with IAS may also present with parkinsonism following repeated episodes of shunt failure.2,3 Although the gait disorder of IAS has not been fully characterised, it shares similar features with that of normal pressure hydrocephalus of the elderly. Here, we report on two patients who presented with festination as the leading symptom of IAS.
A 59 year old man had a seven year history of gait disturbance. During the months before admission, he became more unsteady and he was not able to walk without assistance because of pronounced hastening of his steps. He fell frequently. For several months, no diagnosis was made and his gait disorder was considered possibly to be psychogenic. Only after imaging studies showed pronounced triventricular hydrocephalus was he referred for further evaluation and treatment. On admission, he also reported occasional nocturnal urinary urge and incontinence. The most remarkable finding of his physical examination was his gait disorder. He was able to walk without falling only when holding on to a handrail or to the wall. When he walked freely, his stride length became successively shorter and step height decreased, while his walking speed increased. He was unable to slow his walking speed or to stop abruptly. He then would bend his upper body forward and fall if he could not hold on to a wall or to an object. He could stand without support. On testing of propulsion and retropulsion he had mild postural instability but he recovered unaided. There was no gait ignition failure or freezing when passing through obstacles. Arm swing was preserved when walking. He took several extra steps on turning. There was mild bilateral bradykinesia of his upper extremities but no tremor or rigidity. Otherwise, the neurological examination was unremarkable. He scored 29 of 30 points on the mini-mental state examination. Magnetic resonance imaging including high resolution sagittal constructive interference in steady state (CISS) sequences showed aqueductal stenosis. Lumbar puncture was performed and 40 ml cerebrospinal fluid was drained. One day later, there was mild improvement of the gait disorder. Subsequently, the patient underwent endoscopic third ventriculostomy. The operative procedure and the postoperative course were unremarkable. Within a few days after surgery, further improvement of the gait disturbance was notable. At follow up four months after surgery, festinating gait had completely resolved and the patient could walk freely without assistance.
An 81 year old woman who had previously been well presented with a one year history of weakness and unsteadiness of the legs along with several falls. At the time of admission she was unable to walk or transfer herself independently and had a persistent fear of falling. There had been some urgency of micturition and urinary incontinence, since on occasions she could not reach the toilet in time. The major neurological abnormality was a difficulty in maintaining the erect posture and even walking with the assistance of a Zimmer frame. There was a stooped, flexed posture and festinating gait with short steps. Neurological examination was unremarkable except for diminished light touch sensation in a glove and stocking distribution in the hands and feet. In particular there was no rigidity or tremor, paresis, or impairment of joint position sense. The Middlesex elderly assessment of mental state and Wechsler memory scales showed no significant abnormality. Magnetic resonance imaging showed a lateral and third ventricular hydrocephalus with small aqueduct and normal fourth ventricle. Serial lumbar punctures, which showed pressures from 10–14 cm H2O, had no beneficial or adverse effects. Late onset IAS was diagnosed. The patient underwent ventriculoperitoneal shunting with a medium pressure valve and an antisiphon device. Postoperatively she made a slow but steady recovery. Two months after shunting her postural stability and balance had improved considerably. She no longer walked with a stooped posture and her speed of walking had improved significantly. She is now able to walk around the house with the assistance of a cane.
Festination was the leading symptom of late onset IAS in both patients reported here. Lack of awareness of this association may cause diagnostic difficulties and may result in delayed treatment. This is important, in particular with regard to the observation that cerebrospinal fluid diversion either by third ventriculostomy or by shunting may result in pronounced amelioration or resolution of this peculiar gait disturbance. Hydrocephalic gait usually is characterised by a decreased walking speed, stride length, stride frequency, step height, and foot floor clearance.4 The expression “magnetic gait” fairly well depicts its typical clinical features. The gait may also adopt a shuffling appearance resembling somewhat a parkinsonian gait disorder. It may be classified as both a middle level and a higher level gait disorder according to its clinical presentation and biomechanical evaluations.5,6 Clinical aspects of hydrocephalic gait vary widely depending on the progression of the underlying condition. Gait ignition failure and freezing may occur in as many as 30–50% of patients with idiopathic normal pressure hydrocephalus.7,8 Festination, however, is seen only rarely in hydrocephalic patients but when it occurs it is generally associated with more severe hydrocephalic symptoms and a clinical picture of parkinsonism. It is not fully understood how hydrocephalic disorders induce gait disturbance and parkinsonian symptoms.9 The underlying pathomechanisms may include mechanical distension of fibres of the corticospinal tract and of dopaminergic pathways but also disturbed supraspinal control mechanisms of gait secondary to compromised autoregulation and blood flow in the periventricular and deep white matter. Festination, as well as freezing, cannot be explained by specific neurological abnormalities.10 Festination is seen most frequently in more advanced stages of Parkinson’s disease.11 In patients with Parkinson’s disease, there was no association between significant postural reflex abnormalities and festination but a significant association was found between festination and freezing as reported in the activities of daily living part of the unified Parkinson’s disease rating scale. Festination is considered to be a clinical feature of a subcortical hypokinetic gait disorder. Festination in the presented cases of IAS may have been related more specifically to distension of the third ventricle. The anatomical substrates of festination have not been elucidated but it is most likely related to functional disturbance of diencephalic or brainstem locomotor centres. This assumption would also explain the reversibility of festination after third ventriculostomy and shunting. In summary, this is the first report of the occurrence of festination as the leading symptom of IAS. As shown, festination may be misinterpreted and be considered psychogenic in an elderly patient who otherwise is suffering only mild hydrocephalic symptoms.
Competing interests: none declared