A 73-year-old man developed progressive memory and balance difficulties over 2 months. He initially used a cane, but now requires a walker, with one recent fall. Recently, he has been having difficulty controlling the movements in his hands, with irregular jerks of the right more than left arm. His family has been concerned about progressive memory loss, difficulty concentrating and poor judgment.

PMH: Hypothyroidism, Neutrophilic dermatoses

Medications: Levothyroxine sodium

Allergies: NKDA

Family History: Chronic fatigue syndrome

Social History: Rare alcohol use in past 12 months, previously up to 4 drinks per day; quit smoking 2 years ago after a 25 pack-year history, married; originally from Sweden; retired engineer

ROS: Urinary urgency, weight loss

Physical:
BP 162/92   HR 90  Temp: 37.2 C
General: Drowsy, elderly male. Thin. Easily startled by visual and acoustic stimuli.
HEENT: Neck supple without masses, lymphadenopathy or carotid bruits.
Mental Status: Alert and oriented to self, but not location or time. Recall 0 out of three words at 5 minutes. Intact serial sevens and mental arithmetic, but could not spell W-O-R-L-D forwards or backwards. He had difficulty identifying common objects. He was able to follow simple commands, but became confused with complex commands. Speech fluent, without dysarthria
CN: Pupils were round with sluggish reactivity to light. Extraocular movements were intact without nystagmus, with saccadic intrusion of smooth pursuit. Facial sensation was intact. Normal jaw strength. Normal facial strength. The palate elevated symmetrically in the midline. Normal sternocleidomastoid strength. The tongue was midline with full strength.
Motor: Strength bilaterally: 4/5 biceps, deltoids, triceps; 5/5 wrist flexors, wrist extensors, interossei; 4/5 hip flexors and hip extensors; 5/5 knee extensors and knee flexors; 3/5 ankle dorsiflexors; and 4+/5 ankle plantar flexors. Unable to stand from seated position without assistance.
Sensory: Intact to light touch, pin prick, vibration and proprioception bilaterally in the upper and lower extremities. Romberg: was unable to stand.
Reflexes: 1+ at the biceps, triceps, brachioradialis, patellae and 0 Achilles.  Toes were down-going to plantar stimulation bilaterally.
Coordination: Significant truncal ataxia. Dysmetria on finger-to-nose and heel-to-shin testing.
Gait: Unable to stand without complete assist. Wide-based and ataxic – with assistance.
Abnormal Movements: Frequent movements of all limbs consistent with myoclonus: irregular, sudden, brief, shock-like.
Other Organs: Noncontributory.