The Frontal Lobes: An approach Mark Keezer R4 Neurology Dec 1, 2010

1. In a famous incident in 1848, Mr Phineas Gage, a 25-year-old railroad worker, sustained severe damage to his frontal lobes when a metal tamping rod was blasted through his head after a freak accident... Gage`s accidental frontal lobotomy laid some of the groundwork for the surgical procedure of frontal (prefrontal) lobotomy... This operation became popular in the mid-twentieth century; it was done extensively over a period of years not only for psychosis but also for neurosis and depression... recommended for “difficult children”.

2. The Frontal Lobes: An approach Mark Keezer R4 Neurology Dec 1, 2010

3. Multiple Divisions of the Frontal Lobe • Motor cortex • Premotor & Supplementary Motor cortex • Apraxia • Frontal Eye Fields • Broca’s Area.

4. The Remainder • Prefrontal Cortex • Orbitofrontal Cortex (OFC) • Medial Prefrontal Cortex (MPC) • Dorsolateral Prefrontal Cortex (DLPFC).

5. To begin with... • Sustained Attention • Digit span (7 forward, 4 backward) • Serial 7’s • WORLD • Months/days of the week backwards.

6. Orbitofrontal Cortex • Disorder of Social Conduct (right hemisphere) • Dis-inhibited, impulsive behaviour • Poor hygiene, promiscuity, spending money • Poor judgement and insight • Emotional lability • Euphoria • Witzelsucht (transl: joke addiction) • Facetiousness, inappropriate levity and senseless joking.

7. Orbitofrontal Cortex • On examination • Anosmia.

8. Working Memory (perhaps more OFC) • Verbal & spatial working memory.

9. Medial Prefrontal Cortex (including Cingulate Cortex) • Akinetic/apathetic/abulic syndrome • Paucity of spontaneous movement and gesture • Sparse verbal output • Repetition may be preserved • Urinary (& fecal) incontinence • Micturition centre.

10. Medial Prefrontal Cortex • On exam • Lower extremity weakness.

11. Frontal Gait Disorder (perhaps more MPC) • “...the disorder represents a loss of integration, at the cortical and basal ganglionic levels, of the essential instinctual elements of stance and locomotion that are acquired in infancy...” • Short-stride, shuffling, hesitant steps • Magnetic gait • Ignition apraxia • Turning by small steps with one foot, the other planted as a pivot • Retropulsion.

12. Dorsolateral Prefrontal Cortex • Dysexecutive syndrome • Ability to plan, monitor, and carry out an activity to achieve a goal • Poor judgement • Indifference (almost “la belle…”).

13. Dorsolateral Prefrontal Cortex • On exam • Abstract thought (orange & apple, chair & table, watch & ruler, tree & ant) • Judgment • “You arrive in Vancouver, you’ve lost your friend’s phone number and they are not listed in the phone book. How do you find them?” • Executive function • Perseveration due to difficulty abandoning the initial pattern of responses.

14. Executive Function • Go-no-go (inhibitory control; 1=2, 2=0) • Conflicting instructions (sensitivity to interference; 1=2, 2=1) • Louria sequences (fist, edge, palm) • Lexical fluency (>11 words in 1 minute = normal) • Trails • Clock drawing • Stroop test • String of M’s and N’s • Applause sign. G L A S S T L C C

15. Frontal Release Signs (perhaps more DLPFC) • Palmar grasp • Don’t warn them, just lay their hands down and touch then and see if they hold your hands spontaneously • Glabellar tap (Meyerson’s sign) • Palmomental reflex (the only with localization value) • Snout reflex • Rooting reflex • Utilization behaviour • Echolalia & Echopraxia.

17. A popular procedure was the “ice-pick” lobotomy in which an ice pick was inserted above the eye and pounded through the orbital roof with a mallet, then swept to and fro... The primary proponent of this technique used a gold-plated ice pick and kept speed records for the procedure. A lobotomy was once done on an eccentric actress who had no mental illness... The procedure has been abandoned.